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107: Does it Have to be Heavy? Rethinking the Lift Heavy Shit Narrative. image

107: Does it Have to be Heavy? Rethinking the Lift Heavy Shit Narrative.

S7 E107 · Movement Logic: Strong Opinions, Loosely Held
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In this episode of the Movement Logic Podcast, we take a hard look at one of our own core messages and ask: does it have to be heavy to build bone? We unpack a landmark systematic review and meta-analysis that compared more than 100 exercise interventions in postmenopausal women, looking at low, moderate, and high intensities across resistance training, impact, and combined programs.

We explain the big picture: resistance training works across intensities, moderate intensity often performs just as well as heavy, and impact-only isn’t the standalone solution it’s often made out to be. We also highlight how few truly high-intensity trials exist, why that matters, and what it means for interpreting the data.

Along the way, we reflect on why it’s important to update your message when new evidence emerges, and how this research shifts—not our programming, but our language—around lifting heavy. You’ll come away with a clearer understanding of what actually builds bone, what the science says (and doesn’t yet say), and why there’s more than one effective way to get stronger bones.

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00:00 Introduction and Episode Overview

09:37 New Research on Exercise Intensity and Bone-Building Exercise for Postmenopausal Women

37:08 About the Systematic Review and Meta-Analysis

52:20 Meta-Analysis Results Overview

54:16 Lumbar Spine Analysis

59:00 Femoral Neck Analysis

01:01:43 Total Hip Analysis

01:02:40 Key Takeaways and Summary

01:04:17 Meta-Regression Insights

01:09:47 Clinical vs. Statistical Significance

01:14:14 Discussion on Bias

01:17:26 Engaging with the Community and Expert Opinions

01:39:46 Debunking Myths About Women and Heavy Lifting

01:40:39 Addressing Misconceptions around Lifting Heavy

01:47:25 Cultural Shifts and Women in Strength Training

02:05:58 Practical Benefits of Heavy Lifting

02:11:44 Final Thoughts

REFERENCES:

LIFTMOR Trial and YouTube video

Kistler-Fischbacher Systematic Review with Meta-Analysis

91: LIFTMOR, Not Less: An Interview with Professor Belinda Beck

Stu Phillips IG page and post

Korpelainen paper

100: The Hidden Cost of "Just Do Something" Fitness Advice

Recommended
Transcript
00:00:00
Speaker
La la la la la. Me me me me me. La la la la la. Me me me me. Okay, i think we're ready.
00:00:11
Speaker
Okay.

Introduction of Hosts and Mission

00:00:12
Speaker
I'm Laurel Bebersdorf, strength and conditioning coach. And I'm Dr. Sarah Court, physical therapist. With over 30 years of combined experience in fitness, movement, and physical therapy, we believe in strong opinions loosely held. Which means we're not here to hype outdated movement concepts.
00:00:28
Speaker
or to gatekeep or fearmonger strength training for women. For too long, women have been sidelined in strength training. Oh, you mean handed pink dumbbells and told to sculpt? Whatever that means, we're here to change that with tools, evidence, and ideas that center women's needs and voices.

Podcast Approach and Season Launch

00:00:44
Speaker
Let's dive in.
00:00:59
Speaker
Welcome to the Movement Logic Podcast. My name is Laurel Beaversdorf and I am here with my co-host, Dr. Sarah Kort, DPT. Hello. What's up? What's up? Sarah.
00:01:11
Speaker
We are in episode, what is it? I don't even know. 107? It's episode one of season seven. is 107. It might be episode 107. It exactly is 107. We didn't plan that.
00:01:23
Speaker
How are we doing with this season?

Passion for Research and Problem-Solving

00:01:27
Speaker
Well, what's funny is that even though this is the first episode that you're hearing of the season, we have already done so much work for this season. We've recorded multiple episodes already.
00:01:36
Speaker
two Three. Three. Lauren's interview and the menopause one. And the menopause one. and Oh my gosh, you're right. Yeah. We've recorded a lot already. Yes, we have. And we've done a lot of researching, which is oh my gosh yes the part we probably spend the most amount of time on.
00:01:51
Speaker
Yes. We both enjoy the researching. We say this all the time, but like and this is sort of like me going back to school in a way. because it's like i But like school that you want to do and there's no classes that you have to take that you are know that you're not going to enjoy.
00:02:04
Speaker
And frankly, I find that I'm learning a lot more from this process than I think I've ever learned in any class in school. Probably. Yeah. um Because I think what makes it a very rich learning experience is that I am trying to solve problems that I care about.
00:02:22
Speaker
Right? Right. yeah And it makes it so much more engaging and it makes me work so much harder. Absolutely. Yeah. It's sort of like, I feel like there's ah an undergraduate course at NYU where you basically are like, I just want to do these things. And they're like, okay. And they give you a degree. Like there's definitely, there's definitely like a college version of this, but for two people who are, i mean, obsessed maybe is ah too strong of a word, but very, very focused and interested in health, fitness, exercise, fitness,
00:02:53
Speaker
and all of the nerdy stuff that goes along with it, you and I are like a couple of pigs and shit with this. Like we're just right so happy. Yeah. And I think totally.

Creating Supportive Strength Training Environments

00:03:03
Speaker
And I, and I think that what might give me an extra push too, is the angle that we often take, which is to find ways to help women make their way towards strength training.
00:03:17
Speaker
Right. And so then we get to bring in the, psycho social components of exercise and discuss those alongside the science. Yeah.
00:03:28
Speaker
Yeah. That's I feel like the fire under my my bottom is that bottom, by the way, is your bottom fire refers to as butt. No, that's very good. I like bottom. It's very I remember taking a yoga class with an English woman one time and she was like, take your bottom and put it. but And i was like, oh,
00:03:46
Speaker
all right, I'll put my bottom over here. Like it felt very polite. Yeah. I think it's very, maybe British and Southern. Southern. Yes. Yes. I think there's a lot of Southern and British overlap. I personally just say, but that's what I call that part of the body in the house, but she, she comes home and she would like to call it bottom.
00:04:03
Speaker
like therere Fair enough. yeah So then we play board games. I'm like, man, you're really whooping my bottom.
00:04:11
Speaker
And she doesn't bat an eyelash. I mean, that's the word. Yeah. That's funny. All right. well Well, before we get started on today's episode, I want to direct you to our interest list for the bone density course that we are launching and beginning soon. We're starting November 6th, but we will be talking more about it in future episodes of this season.
00:04:34
Speaker
So when you join the interest list, you get to find out about the course, how to enroll. You get $100 off of the cost of enrollment. And then you also get a lot of freebies, free content from the course.
00:04:48
Speaker
We created, I'm very excited to say, a very helpful tool on our website to help you always know what weight to select for the target rep range that you're using in strength training. You'll get all of this stuff delivered to your inbox. So Even if you don't sign up for the course, you get all of this free education. So yeah go ahead and head to the link in our show notes and get on the interest list for this fall's bone density course, Lift for Longevity.

Evidence-Based Fitness and the Importance of Heavy Lifting

00:05:14
Speaker
All right. If you've been listening to Movement Logic, you know our rhythm by now. We take a claim that's been oversimplified, or we take a claim that is just plain wrong, and we add the nuance, it's missing, and or we correct it.
00:05:30
Speaker
We've done this with the idea that older women shouldn't lift weights, that strength training is dangerous, that yoga and Pilates are enough to build bone, or that posture needs to be fixed or perfected before you can train your body meaningfully with exercise.
00:05:48
Speaker
That's our ethos. We give you what's actually supported by evidence, not just what's good marketing. And true to our taglines, strong opinions loosely held, when better evidence comes along,
00:06:01
Speaker
we update our views. Today is one of those days. Since launching our bone density course, Lift for Longevity, we've emphasized lifting heavy shit.
00:06:12
Speaker
And we weren't alone. The LHS lift heavy shit movement took off in the last decade, born, I think, as a rebellion against decades of tone, don't bulk messaging that kept women underloaded.
00:06:26
Speaker
Social media and from my perspective, CrossFit helped normalize heavy lifting specifically with barbells. And suddenly women everywhere began setting down their pink dumbbells in favor of bigger, heavier weights.
00:06:42
Speaker
Around the same time that women were picking up heavier weights, research on hypertrophy, which is increase in muscle size, was showing that heavy was not best for hypertrophy. And in fact,
00:06:55
Speaker
you could hypertrophy muscles with light weights, moderate weights, and heavy weights. However, this research was also showing that heavy lifting still had a clear edge for building maximum strength, which is the ability to produce maximum force.
00:07:13
Speaker
So since strength gains were understood to rely most on heavy loads, the theory held that bones follow the same rule. If heavier was better for strength, it was probably better for bone.
00:07:27
Speaker
The idea that heavy weights were better for bone also fits neatly with longstanding theories like Wolf's Law, the idea that bone adapts to the forces placed upon it, and the mechanostat theory, which says bone responds most when loads create enough strain to cross a threshold.
00:07:45
Speaker
On top of that, animal studies seem to back it up. Experiments in rats and other models show that bones respond to high magnitude, high rate loading. Put all of this together, and heavy lifting looked like the most biologically plausible way to stimulate bone formation in humans.
00:08:01
Speaker
And while it didn't get a lot of ink spilled about it, because there wasn't a lot of conclusive research to go on, Personal training educational textbooks espouse this idea that bones probably required high magnitude and high rate of loading.
00:08:17
Speaker
So before researchers tested heavy lifting and high impact in post-menopausal women, most high load trials were on younger adults, which showed loading could nudge bone mineral density up or help maintain it, though the skeletal effects were usually modest compared with the clear strength and muscle gains.
00:08:39
Speaker
In kids and teens, the evidence is much stronger. High impact, high force activities during youth lead to lasting skeletal benefits. And studies on athletes make this clear.
00:08:51
Speaker
Sports like gymnastics and volleyball, both power and impact heavy, are especially effective for stimulating bone growth. In contrast, sports like swimming and cycling provide little benefit for bones since they involve little to no impact.
00:09:06
Speaker
Swimming in particular keeps the body buoyant, which

Research and Trials on Bone Health

00:09:08
Speaker
reduces the mechanical loads bones would otherwise experience. This lines up with what we know, which is that during your youth, this is the peak window of responsiveness for building bone, and high-impact activities are a superior way to stimulate it during this period of life.
00:09:26
Speaker
But theory is one thing, and direct evidence is another. And until recently, the evidence for postmenopausal women, the group most at risk for bone loss, was basically non-existent.
00:09:39
Speaker
Most of the high-load trials had either been done in younger adults or in animals. Probably the best explanation for a paucity of trials is that postmenopausal women, especially ones with osteoporosis or a history of fracture, were often considered too fragile for these kinds of experiments.
00:09:58
Speaker
So the assumption that high loads were best for bones went untested in the very population that needed answers most. Against that backdrop, the LIFTMORE trial was a turning point.
00:10:11
Speaker
The first major randomized controlled trial to test heavy bone targeted training in the population that needs it most. We've talked a lot about LIFTMORE and will more in this episode.
00:10:24
Speaker
Now, in light of some other evidence we'll be discussing today, while heavy lifting remains an effective approach for bone building for postmenopausal women, the best evidence we have now from a systematic review and meta-analysis shows that it's not the only way.
00:10:42
Speaker
And in some cases, for some sites, it may not even be the best way. So we're going to go into detail about this paper, but one of the most important things to know right off the bat is this is the first review of its kind to actually compare high or sometimes called heavy, moderate, and low intensity exercise interventions against each other in the post-menopausal women population.
00:11:09
Speaker
Past research has either grouped the intensities together or compared one intensity against a no-load or a very low-load control group.
00:11:20
Speaker
What is also important to note is that intensity is often poorly defined in the literature. One study's heavy might be another study's moderate, and some studies don't even quantify it at all.
00:11:33
Speaker
So the authors of this review tackled that problem by setting clear, consistent definitions for high, moderate, and low intensity across all the included studies. That makes it a great opportunity to see how these different training intensities actually stack up against each other in the same analysis.
00:11:53
Speaker
So this is at the heart of why we are changing our message away from it has to be heavy for bones. The best available research suggests that it's not entirely true with what we know at the moment.
00:12:06
Speaker
What you're going to learn in a moment is that there's a huge gap and a huge lack of high-intensity studies. Essentially, we're going to be a little less specific about which intensity is best because it does appear that a variety might work for bone building.
00:12:22
Speaker
But with that said, we still think you should lift heavy shit, and we'll tell you why. Since we encountered this paper back in late April of this year, we began adjusting our message.
00:12:36
Speaker
You might have noticed that in a few recent episodes, we've mentioned that heavy may not be the only way to build bone, and we gave you a heads up that you'd be hearing more from us about it. And here we are, telling you more, a lot more.
00:12:48
Speaker
But in today's episode, we're going to also make a big deal about this. We are stating outright, on air, without spin, that we were wrong to suggest that lifting heavy was the only way to build bone.
00:13:03
Speaker
We were not taking into account the breadth and depth of the literature. And we want to correct the message that you have to lift heavy to build bone. Because we now understand that based on the best available evidence, that's not a claim we can make with a high level of confidence.
00:13:21
Speaker
So we're not doubling down. We're not ignoring this evidence. Nor are we just gradually and subtly going to shift our message toward, and you can also lift moderate without acknowledging the message, it has to be heavy, is inaccurate.
00:13:37
Speaker
We're also not going to shift the goalposts to, well, what we meant by heavy was more heavy. Or when we said heavy, we meant relative to your capacity, which for some people is actually moderate.
00:13:51
Speaker
That's a dodge. Yeah. we meant heavy, as in high, as in how this paper defines it, which is also the widely accepted definition of high in exercise science.
00:14:02
Speaker
So we aren't shifting the goalposts to gloss over our original claim. Instead, we're admitting that this claim that it has to be heavy is not representative of the bigger body of evidence out there that until this systematic review with meta-analysis, we were frankly unaware of.
00:14:23
Speaker
It's hard to admit you're wrong, right, Sarah? Why do you think it's so rare for people to do this publicly? Yeah. Well, I mean, i think at least part of it is it's really uncomfortable.
00:14:36
Speaker
Like you and I have been working on this episode for, well, mostly you, let's be clear, have been working on this episode for a while, but we've been working with this idea that we know that we need to change our message.
00:14:48
Speaker
And even having had that in my head for a while now, just this part, like it's giving me icky feelings in my stomach just right now talking about this. Because yeah I think, I mean, like speaking for myself, I think my my fear is that if I admit that I got something wrong, it's going to damage my credibility.
00:15:13
Speaker
And then I'm not a trusted resource anymore. Right? So it's this, there's, there's certainly a sense of like, I have to be perfect all the time. Otherwise people will not take me seriously or, you know, that kind of a thing.
00:15:26
Speaker
um But I think the reality actually is that you start to get taken not seriously when you encounter new evidence and then you're like, yeah, but, and still try to stick to what you were saying rather than shifting.
00:15:39
Speaker
I think for some people, you know, this also translates to, and then because I'm not credible, people will not buy my thing anymore. Right. So yeah in that instance, I think it feels safer to just stick with your, you know, hold to your narrative and just ostrich head in the sand, ignore any new evidence to the contrary.
00:15:59
Speaker
Yeah. Yeah. And, and we're going to talk about this, but this is especially difficult to admit if something that it, you took seriously, weeks, months, years to build ah product that you sell yeah is no longer relevant in the face of this new research, which we luckily do not have that problem with our course, which we're goingnna we're going to tell you about. It's very interesting. yeah um But yeah, I agree. i I feel like this fear of admitting you're wrong is very much tangled up in capitalism. you know It's more important actually to protect
00:16:37
Speaker
profit margins than it is to be open and honest and transparent about yeah what is right and and correct and what is incorrect and where you stood and where you stand. And that might involve correcting yourself, right? And admitting that you were wrong. Yeah.
00:16:52
Speaker
But I think we should normalize admitting when we're wrong. I think it's very freeing. Yeah. Because if you can't ever be wrong and if you can't ever fully participate in your own learning on a transparent, open level, especially if you're an educator, especially if your whole thing is helping people think critically.
00:17:16
Speaker
If you can't ever admit when you're wrong and correct that, you never really get to fully participate in what real learning actually looks like.
00:17:28
Speaker
yeah right And you never get to model what real learning has to entail. Which is getting you wrong. Right? yeah You're always kind of stuck hiding from or defending your past instead of growing openly into your future.
00:17:47
Speaker
Yeah. Quick anecdote about this. Years ago, so I was talking to Jules Mitchell and we were we were talking about like blog posts from five to 10 years prior and how we were kind of like embarrassed by them now because we know more now. Yeah.
00:18:03
Speaker
But ah my argument was like, yeah, we should, that's how it should be. you should, you shouldn't look back at something you did 10 years ago and be like, yep, I've learned nothing since then. And right I have, I've just been right all along.
00:18:16
Speaker
never make mistakes. All along. You said right all along. Right all along.
00:18:21
Speaker
A little Freudian slip there. yeah But yeah, you know that that that is that's learning. That's that's growth, right?

Course Structure and Impact of LIFTMORE Trial

00:18:29
Speaker
And we want to be really clear about what this new evidence actually says, which is heavy isn't the only way for postmenopausal women to improve their bone mineral density.
00:18:41
Speaker
but it still is an effective way. And that is a message we are gonna continue to promote. And it's also worth pointing out, despite all the attention that heavy lifting gets, high intensity resistance training has been studied the least.
00:18:55
Speaker
So this paper analyzed 120 other papers other papers And of those 120, only six were high intensity because that's literally all there was to pull from. They didn't leave any out.
00:19:06
Speaker
There is an enormous gap in the literature. And as more research comes out, we'll get a clearer picture of how high intensity stacks up against the others. Not to mention as well, we're still always going to be proponents of lifting heavy shit for all its other benefits. Yep.
00:19:21
Speaker
So here's where we're going in today's episode. First, we're going to walk you through what this new research shows about high, moderate, and low-intensity exercise interventions, including resistance and impact training for bone health.
00:19:33
Speaker
Now, when we say resistance training, we mean both the S&C kind, the strength and conditioning kind, the kind that personal trainers learn to deliver, but also looser definitions of it that this paper adopted, like Tai Chi, Qi Gong, Pilates, right?
00:19:52
Speaker
And in the case of impact training, things like dancing, line dancing, walking at various paces. All right, so these are all, in addition to more traditional forms of resistance training and more traditional forms of impact training in this particular paper, grouped into altogether categories of either resistance training or impact training, or a combination of the two.
00:20:17
Speaker
OK, then we'll talk about how we became aware of this paper and the discussion going on around it online. We'll end by getting into the bigger picture of how the lift heavy shit narrative, like a pendulum swinging, started as one way to empower women and challenge the idea that lifting heavy is dangerous or inappropriate or off limits for them.
00:20:42
Speaker
but how like any pendulum, it risks swinging far in the other direction, away from accessibility and into exclusion if it becomes too absolutist, as in heavy or bust. And I just want to add, because this is one of our themes for this season, you will hear heavy or bust, not just for bone building, but you'll also hear heavy or bust for cortisol, heavy or bust for muscle growth, which we know is untrue.
00:21:12
Speaker
Decades of research show that. You'll hear heavy or bust for pretty much anything that women are struggling with during the menopause transition.
00:21:23
Speaker
And this is what we mean when we say that the pendulum can swing toward exclusion and become very simplistic and also inaccessible.
00:21:35
Speaker
We'll also discuss our opinions around why we think some people do resist lifting heavy or even lifting heavier where beliefs come from that it's dangerous or inappropriate or big weights are scary and why we think it's worth questioning these beliefs.
00:21:53
Speaker
Finally, we'll discuss what this new insight from this paper we're discussing today means for our bone density course, which I kind of already gave it away, but pretty much not much because ironically,
00:22:08
Speaker
And happily, our course has always included a mix of intensities because frankly, only a total lunatic would take untrained people, which the majority of people who sign up to take the course with us, and start them with heavy lifting. yeah Most of the work in the course happens at moderate intensity.
00:22:31
Speaker
Most of it actually stays at moderate intensity for the entire course. yeah A small percentage of exercises progress toward heavy. All of it is scalable to the individual thanks to the individualized coaching that Sarah and I provide throughout the entire six months in twice weekly live classes and inform check videos in the Facebook group.
00:22:54
Speaker
What is changing is our messaging. We are definitely going to be softening the it has to be heavy line. We might even be directly questioning it more often.
00:23:06
Speaker
Because right now, in the face of the evidence we have today, we just can't make that claim with confidence because it just appears to be not that simple.
00:23:17
Speaker
Right, Sarah? It's rarely simple. Rarely. All right. So let's go backstory mode for a second. We got to tell you about how we encountered this paper. We first found out about it because of an Instagram post from an esteemed professor, Dr. Stuart Phillips, out of McMaster University in Canada. Sarah, do you remember when people started pelting us with this Instagram post?
00:23:43
Speaker
Yes. Have you seen this? Yes, we got so many DMs from people being like, have you seen this? Have you seen this? Why is he saying that? people People were confused. Some people were upset. you know The post kind of rocked a few people's worlds. And honestly, it rocked our world a little bit too. When we finally did watch the video, we had to pause because Phillips wasn't just making passing comments. He was highlighting that the data showed moderate intensity training actually looked better for the hip than high intensity.
00:24:15
Speaker
And that across the board, different intensities seemed basically equivalent for bone. And that cut right across our it has to be heavy message.
00:24:26
Speaker
And, you know, our reaction was, ah he's probably right. He knows this literature inside it out. And if he's pointing to something we've been missing, we need to take a really close look at it. So that's what we did.
00:24:38
Speaker
We'll come back to Philip's post in more detail later, but first let's talk about the actual systematic review and meta-analysis. Shall we? Let's get into it. The paper is titled, Effect of Exercise Intensity on Bone in Post-Menopausal Women, a Systematic Review and Meta-Analysis.
00:24:52
Speaker
And it was published in 2021. It is a two-parter, a systematic review with meta-analysis. This type of paper is way up toward the top of the evidence hierarchy.
00:25:06
Speaker
The systematic review part tells you the lay of the land, a literature review of sorts, what's been studied, how well it's been studied, and where the strengths and weaknesses are. And it's all written out narratively.
00:25:20
Speaker
Part two, the meta-analysis then zooms in with a more statistical, perhaps objective lens, pulling the data to see if the effects of the intervention hold up when all the evidence is combined together.
00:25:35
Speaker
Now, I think the only thing higher up on the evidence hierarchy would be a systematic review of systematic reviews with meta-analysis, right, Sarah? Yes. right So this is just below that. The authors of this paper are lead author Melanie Kistler-Fischbacher, Benjamin Weeks, and Belinda Beck from Griffith University in Australia.
00:25:55
Speaker
Beck, whose name you probably recognize listed last, is the senior author. And the reason you might recognize her name is because she's one of the authors from the landmark Liftmore trial that we have mentioned many times on this podcast and we mentioned earlier in this episode.
00:26:10
Speaker
This randomized controlled trial was published in 2017. We've talked about the Lift More trial often on this podcast, and Sarah and I have even interviewed Professor Beck herself. We're going to link everything that we mentioned to you about every study, every person, every social media post in the show notes today.
00:26:28
Speaker
So if you don't hear me say it again, make sure you check the show notes for all of the resources mentioned. Now, want to take a step back and reflect for a second as it relates to the Lift More trial. Sarah, was thinking about it, and I think it's pretty accurate to say that the Lift More trial is the reason this podcast exists, and it's the reason Bone Density Course exists.
00:26:49
Speaker
Am I right? Before we started the podcast, we were at a point where as MovementLogic, we had made six continuing education tutorials on different body areas that were aimed at movement teachers of all kinds. And we felt like we didn't want to do any more of those. We felt like we'd kind of done enough of those.
00:27:07
Speaker
At the same time, we were talking about heavy lifting and the already well-known benefits to muscle and other soft tissues with heavy lifting and how that was a direction we wanted to now go in.
00:27:18
Speaker
Then we saw the Lift More trial and how it showed heavy lifting was both safe and effective to improve bone density for women with osteoporosis or osteopenia. So we decided we wanted to teach women how to lift heavy.
00:27:32
Speaker
I will say, though, our choice to do barbells yeah exclusively had a lot more to do with this sort of patriarchal worldview that barbells were not for women. Yeah.
00:27:43
Speaker
We were just generally sick and tired of the underloading. sold to women as exercise to stay skinny, right? Don't get too bulky.
00:27:55
Speaker
Or in the yoga and Pilates community, this dogma that yoga and Pilates met all your needs, that it was all you needed to do. We knew also with barbells, we'd never have to beg anyone to buy a heavier weight, as I often found myself doing very frequently with members of my virtual studio, taking my kettlebell classes.
00:28:17
Speaker
ah Because once you have set of barbells, you're basically set with all the load you'll need for life. And I found that training middle-aged older women at home it was difficult to convince them they needed or would benefit from purchasing more weight. So Sarah and I were like, let's just one and done it and have them get a set of barbells.
00:28:39
Speaker
Yeah. Yeah. We also, we were like, oh, do we do dumbbells and kettlebells and barbells? And then it just got so complicated. And expensive. Yeah. Right. It became like this whole thing. We're like, okay, let's mix the, let's just get to the point. Sometimes you just, you have to pick a lane, right? And a point of view and stick with it.
00:28:56
Speaker
But we were also wondering ourselves about, I mean, i was, I won't speak for Sarah. I was wondering myself about the safety of lifting weights, especially heavy ones for our demographic of women who were trying to build bone.
00:29:10
Speaker
And when I encountered Lift More, which applied what I like to call the third rail of exercise prescription, so high intensity, high intensity strength and impact training. to women who were not only older, right, postmenopausal, but who had also suffered a history of fracture and they found that it was safe.
00:29:31
Speaker
I was like, well, all right, let's go. yeah Yeah, me too. So LIFTMORE was what's called a randomized controlled trial or RCT. That means that participants were randomly assigned to different interventions. So either a high intensity resistance and impact program or a low load control program so that any differences in the outcomes could be more confidently attributed to the training itself rather than other possible confounding factors.
00:30:03
Speaker
And that's important because An RCT is a single study. So that means it's automatically lower on the evidence hierarchy than a systematic review or a meta-analysis, but it is the gold standard for testing cause and effect.
00:30:19
Speaker
So as a single trial, it's the absolute best kind that you can do. As well as the randomization, it also means they had a control group to compare against, which is important because if we're trying to determine the efficacy of a treatment or intervention, we need to know what happens to people who don't do it as a comparison.
00:30:37
Speaker
So for Liftmore, postmenopausal women with low bone mass, including some who had a history of fracture, were assigned to either this high-intensity resistance and impact training program, or what they call high RIT, or to a low-load control program.
00:30:54
Speaker
And what they found was that over eight months, the high-rit group increased lumbar spine bone density by almost 3% and saw smaller but still meaningful improvements to bone density at the hip.
00:31:08
Speaker
Eight months is actually not a lot of time to make changes to bone. In fact, it's it's probably about the shortest timeframe that you would want to use if you're studying how load affects bone.
00:31:20
Speaker
And this is because bone remodeling takes place at a much slower pace than something like muscle. A single cycle of bone remodeling where old bone is broken down and replaced with new bone, it takes about three to four months.
00:31:34
Speaker
Even after that time, the changes are really small because bone adapts over repeated cycles. So to see really meaningful shifts in bone density on a DEXA scan, you're usually looking at a minimum of six to 12 months or maybe even longer. That's why you don't go get repeated DEXA scans more than once a year.
00:31:53
Speaker
So LiftWare was far longer than a lot of studies on bone. And the fact that it takes so much time to build bone and you have to work at it consistently is probably the biggest single reason we don't have a lot of great research on bone building. It's expensive.
00:32:10
Speaker
It's expensive. it's I mean, from ah from a research perspective, that is a really long trial. You're going to get so much drop off. There's going so many things that happen in that time period. So it's very hard to do.
00:32:21
Speaker
ah But I'll say it again. The most important takeaway from the Lift More study was that this high-intensity resistance and impact training intervention was safe. There was only one injury reported in the entire paper.
00:32:35
Speaker
Yeah, and it was safe when... Technique was not perfect. Like, do you remember the YouTube video? Yeah, yeah. I'll find it. I'll try to find link that in the show notes as well.
00:32:46
Speaker
The YouTube video shows women who are definitely in their 60s, some in their 70s,

Safety and Effectiveness of High-Intensity Lifting for Older Women

00:32:53
Speaker
lifting heavy barbells in a deadlift with very rounded spines.
00:32:58
Speaker
And they are being helped up to a pull-up bar, pulling themselves up above the bar, and then just dropping and landing with stiff legs. And you're like, i i can't believe what I'm seeing. And also, fuck yes.
00:33:15
Speaker
Yeah. I mean, we're so we're so accustomed to seeing older women in particular being handed little dumbbells and you know so taking a chair yoga class or something like that, that to see these women where instinctively we look at it, we go almost like, oh no.
00:33:30
Speaker
But the fact that fact that they were not only able to do it, but nobody, one person hurt themselves, I think. And there was a significant ah bone density increase. It's like, we need to we need to change our eyeballs out.
00:33:43
Speaker
We replace them with fresh eyeballs that are not so conditioned to believe that older women are frail and should be handled like a China doll. I think that's a wonderful way of summarizing Liftmore, that it gave us a very fresh perspective yes what's possible.
00:34:01
Speaker
Yeah, for sure. The discovery that high intensity resistance and impact training was safe was one of the most groundbreaking aspects of the Liftmore trial because it, frankly, directly tested what many saw as just too dangerous, too risky for this too fragile population.
00:34:19
Speaker
Yeah. Still, Liftmore, for as acclaimed as it's been, especially on our podcast, hasn't gone without criticism. One of the main critiques is that the control group did very low intensity work, not even low intensity resistance training, just low load work, unlikely to improve bone, which sets the bar for comparison so low that the high-intensity program was almost guaranteed to look better.
00:34:47
Speaker
In other words, the results, remember that they were statistically impressive for the lumbar spine and modest for the hip, may partly reflect the weakness of the control, not just the strength of the intervention.
00:34:59
Speaker
Yes, but I just want to like do a little devil's advocating here. That issue about the control is only a real issue if you're actually trying to determine which of all the types of interventions is the best one.
00:35:14
Speaker
I think what Liftmore was really concerned with was showing that high intensity was both effective and safe yeah for postmenopausal women with osteoporosis, which it did.
00:35:25
Speaker
And it's definitely important to know like which of all is the most effective. But we can't answer all the questions out there with just one study. Yeah. The primary study aim, according to Liftmore, was to determine the efficacy of HI-RIT, right? That's high intensity resistance to impact training, for improving lumbar spine, femoral neck, bone mineral density in postmenopausal women with low to very low bone mass.
00:35:52
Speaker
Their hypothesis was that it would outperform the control. Assessing the safety was a secondary aim for which they predicted it would be safe, as safe as the control.
00:36:04
Speaker
And I think of the two, I think the results were most groundbreaking on the safety side. Yeah. Because in terms of outcomes, Liffmore found that statistically high RIT was superior to low load control for the lumbar spine and then also femoral neck cortical geometry.
00:36:22
Speaker
but also, of course, all major strength and functional measures. Clinically, and we're going to talk a little bit in this episode about the difference difference between statistical and clinical significance, but clinically, it found that lumbar spine bone mineral density improved about 3%, which is a meaningful gain in a population that would otherwise be expected to lose bone, and that functional strength increased by between 35% and 36%.
00:36:48
Speaker
Back extensor strength, sit-to-stand strength, a change large enough to directly impact daily function and, of course, also fall risk.
00:37:01
Speaker
Now, as I mentioned, femoral neck bone mineral density gains were smaller in absolute terms, but the fact that the high RIT halted the typical decline at this site is clinically important given hip fracture risk.
00:37:16
Speaker
But certainly the most groundbreaking result was that postmenopausal women with low bone mass tolerated high-intensity lifting safely. And this overturned long-standing assumptions that they were too fragile for this kind of training.
00:37:31
Speaker
But again, LiftMore was a single RCT. And while RCTs, as Sarah said, are powerful for showing cause and effect in a controlled setting, it's still just one data point.
00:37:44
Speaker
Though As data points go, it's a particularly good one. Most research done on bone building for post-menopausal women is pretty low quality. Yeah. Okay, so let's go back to the systematic review and meta-analysis that we're talking about today.
00:38:00
Speaker
This combination of the systematic review and meta-analysis puts Liftmore and dozens of other bone training trials into a much bigger context.
00:38:11
Speaker
Instead of just looking at a single study, it gathers results from over 100 trials, judges their quality, and statistically combines their findings. And it asks a simple but huge question.
00:38:25
Speaker
What exercise intensities are actually sufficient to stimulate bone building in post-menopausal women? And like we've been saying, most reviews in the past don't make this comparison, right? This one does. It compares low, moderate, and high intensity against each other, head to head.
00:38:48
Speaker
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00:39:05
Speaker
You might be wondering, am I doing the right kind of training to actually support my bone health? What's the smartest way to keep my body strong without risking injury? What's the best way to modify lifts if I have joint pain or past injuries?
00:39:18
Speaker
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00:39:42
Speaker
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00:39:57
Speaker
So this was a two-part project. Part one was the systematic review. That's the qualitative part where they sift through and summarize all the relevant studies that meet their criteria and report it narratively. They describe what they find.
00:40:12
Speaker
And then part two is the meta-analysis, which is the quantitative part where they pool the numbers from these studies to calculate the overall effects. And then they're able to make things like a forest plot and other graphs and things to show how the data lined up.
00:40:27
Speaker
So the systematic review, the first part, it cast a really wide net. It included 100 trials, 120 interventions.
00:40:38
Speaker
What's the difference? Oh, some trials had multiple interventions. Thank you. Each one lasting at least six months in healthy post-menopausal women. Bone outcomes had to be measured by DEXA at the lumbar spine, femoral neck, or total hip.
00:40:54
Speaker
And most importantly, the bones had to actually be loaded by the exercise. Now, the range of programs was enormous. Because on one end, you had traditional resistance training and impact protocols, right? Like jumps, hops, and landings.
00:41:08
Speaker
But then you also had walking, water-based exercise, mat and reform pilates, tai chi, line dancing, step aerobics, agility drills, dance classes, ball sports, stretching, even qigong.
00:41:23
Speaker
Some were multi-component fitness classes and others designed by medical authorities like Spain's program for osteoporosis prevention classes.
00:41:36
Speaker
Reproducibility can be a real problem for many of these interventions because there's no clear way to determine things like intensity and volume. And since intensity is the focus of the systematic review with meta-analysis, for a lot of interventions that they were studying, like Tai Chi, line dancing, water aerobics, it had to be talked over and agreed upon by the authors of the paper.
00:42:00
Speaker
Yeah, they had to sit down and look at the study on Tai Chi, and there were five of them, I think. and go, which bucket are we going to put this in? Was it low intensity? Was it, you know, yeah depending on how well the movements were described and based on their understanding of, you know, like what impact might've been experienced, what resistance the body had to overcome this hour in in the Tai Chi was, it was all low.
00:42:21
Speaker
um I think the line dancing was moderate, which is cool. Yeah. There's a lot of like kicking and. kick it up and Kicking and stomping. Yeah. All right. So they put each intervention into an intensity category.
00:42:33
Speaker
as I said, low, moderate, high. And to do so, they used some standard criteria for these intensities. So for resistance training, it was deemed high if the resistance involved working within a percentage of your one RM, your one repetition max of greater than or equal to 80%. So that's fewer than eight reps if you're thinking about rep targets.
00:42:59
Speaker
For moderate intensity, the cutoff is that it had to have been an 8 to 15 rep target. So that's 60 to 79% of one repetition max. and then for low intensity, it could be less than 60% of a one repetition max or greater than 15 reps.
00:43:17
Speaker
For impact training, it was considered high impact. If bodyweight landing forces were greater than four times bodyweight, if moderate it was two to four times body weight landing forces.
00:43:32
Speaker
And for low, it was less than two times body weight landing forces. Now, I don't think people were line dancing on force plates. So again, i think a lot of these determinations by the authors of the Kistler-Fischbacher systematic review and meta-analysis were like best guesses, okay, based on these trials and the description of the exercise intervention within each individual trial.
00:43:59
Speaker
So for fuzzier modes like Pilates, Tai Chi, Qigong, you know, fitness classes, the intensity was determined based on the paper's description of the exercise, the effort involved, how the movement was described, like walking at various speeds.
00:44:16
Speaker
Water exercises included both aerobic and resistance-based. um Jumping drills could have been like more moderate to high. And i think, you know, for example, with the Pilates example, there was a MAT Pilates trial and a reformer Pilates trial. They put the MAT Pilates trial in the low intensity and they put the reformer Pilates in the moderate intensity.
00:44:38
Speaker
Resistance training was, of all of the intervention types, it was one of the most prevalent. But it ran the gamut from low to moderate to high. Although, as we have mentioned now already, there were really only six trials looking at high intensity exercise.
00:44:55
Speaker
And I think four were resistance training. okay So that's not a lot. Impact training was also prevalent. And it also ran the gamut. They included aerobic activity.
00:45:07
Speaker
So they were counting walking, I believe, and jogging as low intensity impact. Mm-hmm. Running was, I think, moderate or high, and jumping was moderate or high. They also used a highest intensity wins type of a rule.
00:45:21
Speaker
So if a paper looked at moderate resistance training plus low intensity walking, that particular trial was classified as moderate, not low.
00:45:33
Speaker
A trial with both moderate and high interventions was classified as high, so highest intensity wins. All of the control groups for these trials were typically either no exercise or very low load exercise.
00:45:47
Speaker
Taken altogether for the systematic review of 120 interventions 100 papers, 57 of them were low, 57 of them were moderate, and only six were OK. fifty seven of them were moderate and only six were high okay We have to talk about something called the risk of bias, because it's hard to actually create randomized control trials for bone building.
00:46:13
Speaker
Because typically when there's an intervention, then there's a control. If the control is no exercise or it's like very low intensity exercise, like walking, it becomes very clear to people which group they're in, right? Are they in the group that's supposed to improve are they not in the group that's supposed to improve? So that's really, really hard to do.
00:46:34
Speaker
Because it's hard, there's not so many of them, the systematic review included both the randomized and non-randomized controlled trials, and they used something called the Cochrane Risk of Bias Tool, which is a way to assess part of the quality of the study by looking at the bias.
00:46:54
Speaker
You can't blind people to what they're doing, right? Because they're doing it. Getting people, as we said earlier, like just living their lives and then for months and months at a time, take part in a protocol and stick to it is hard.
00:47:08
Speaker
Reporting can be patchy. So what the paper concluded in terms of the potential for bias was that the low intensity studies were generally the weakest and had the highest risk of bias.
00:47:25
Speaker
Many were underpowered. Yeah, that means they just didn't have a lot of people participating in the study. Right. They had poor adherence, or even there was no blinding of the assessors, meaning the people running the trial knew who was doing what.
00:47:41
Speaker
And so they there's always the chance of bias for that reason. Yeah. And I think also the low-intensity trials had the highest prevalence of non-randomization. so they were controlled trials rather than randomized controlled trials, yeah which which increases bias a lot.
00:47:55
Speaker
Yes. And the moderate and high intensity trials were somewhat better designed, but they still weren't flawless. Yeah. right Do you have any thoughts on why the low intensity trials had higher risks of bias?
00:48:08
Speaker
It's a good question. I mean, i think I think because low intensity tends to kind of be a lot more vague generally. Like go take an aerobics class versus lift this weight eight times, right?
00:48:24
Speaker
Not that you can't do sets and reps with low intensity, but I think a lot of the and interventions were not resistance training anyway. So it's like do some Tai Chi. We can't measure how many times you bend your knee. You know what i mean? Like there's not good ways to quantify the data. Yeah.
00:48:43
Speaker
Yeah, like to measure the amount of what happened to people, like the amount of volume, the amount of intensity. I believe a lot of the low intensity trials were were from longer ago.
00:48:55
Speaker
So maybe from the 80s and 90s. And i think also they were designed with the idea that these interventions are just inherently safe. Right.
00:49:06
Speaker
So like walking Tai Chi, because researchers, I think maybe assume these just wouldn't harm anyone. Right. We're dealing with postmenopausal women. Maybe some of them have a history of fracture.
00:49:18
Speaker
Researchers maybe assume that because these wouldn't harm anyone, they maybe didn't need to build in the same level of supervision, standardization, monitoring, rigor.
00:49:31
Speaker
There's this design looseness. And I think that would bump up against the risk of bias, but that's just me thinking out loud. Yeah, I mean, that's possible. I still think researchers always trying to, I mean, good ones are always trying to minimize the confounding factors and things like the risk of bias. So it may have been that. It may also just have been like,
00:49:52
Speaker
It's really impossible sometimes unless you're doing something the way that Liffmore did where people like went to a place and like everybody did that, right? Yeah. If you're doing a study where it's like, well, you're going to take 60 minute aerobics class and we can't really define what happens every single time. Yeah. Cause it's always different. Right. Exactly. Exactly. So I think that's just sort of the nature of low intensity is it doesn't tend to, as you're saying, because it doesn't have to necessarily, yeah it's a lot harder measure sometimes.
00:50:21
Speaker
Yeah. And then I think if I continue along my train of logic, like perhaps moderate and high intensity trials, which tended to be more recent trials and the study designs were better. I also think that like people have gotten better at studying this, right? Yes. um They also carried a higher perceived risk.
00:50:41
Speaker
Right. Like moderate to heavy lifting, moderate to high impact jumps. Right. Maybe because of that, they're better structured. Like, let's make sure people don't do too much. So now we have to know how much they're actually doing.
00:50:53
Speaker
Right. Yeah. Maybe they were better supervised. There was more detailed reporting. yeah But the cool thing is that across all interventions and all intensities looked at in this systematic review with meta-analysis, most injuries were mild, some joint and muscle pain.
00:51:11
Speaker
Serious events were rare. They included a fracture and a surgical ankle injury. Only 2% of participants dropped out due to injury. And those are pretty good results. This this reinforces our message that exercise, across all intensities, is generally very safe.
00:51:27
Speaker
Yes. And the rewards vastly outweigh the risks. Yeah, absolutely. Absolutely. Okay, so that's what they were looking at in the systematic review. Now, when we get to the meta-analysis, they had to be more strict about selecting what trials they compared. So that meant they only looked at the randomized control trials compared to the systematic review where they also included non-randomized control trials. So the data set for the meta-analysis was 53 randomized control trials
00:51:59
Speaker
With 63 interventions, 19 low, 40 moderate, and four high. There's always confounders, right? There's always things that show up that complicate how confident we can be when we are interpreting the statistical results.
00:52:16
Speaker
So here's a couple. The first one is heterogeneity? Heterogeneity. Huh. I don't think I've ever said that. before. Okay. Really?
00:52:28
Speaker
Yeah. I've said heterogeneous. Heterogeneity. It's the noun. Oh. ah You learn something new every day. Okay. So it's hard to say.
00:52:41
Speaker
I don't know why. and this i got that I get up to the heterogene and then I'm like, itty? Hey, itty. Okay. So one of the confounders was heterogeneity, meaning that the trials varied wildly in design.
00:52:56
Speaker
right This was not apples to apples. This was Tai Chi to- Resistance strength. Yeah. you know as i And then the study quality varied as we described. So things like supervision, adherence, measurement sites, recording. We're looking at the average of apples, oranges, and pears.
00:53:11
Speaker
Yeah. And maybe a watermelon. Yeah. the The second thing was there's a lot of study design differences, right? So because there were not a lot of good randomized control trials in the bone building space, the systematic review included both randomized and non-randomized trials, which are automatically lower quality.
00:53:34
Speaker
The meta-analysis sidesteps some of that risk of bias by sticking to randomized control trials only, right? which is a reason to lean on its conclusions over the systematic review conclusions, which were slightly different. We'll we'll get into it.
00:53:53
Speaker
And then the big thing is there were very few high-intensity trials. There were only six in the systematic review out of 120. There were only four in the meta-analysis out of 53. That makes firm conclusions about high-intensity trials.
00:54:09
Speaker
tentative at best. And it brings us to one of the phrases we say all the time, which is more studies are needed. Yeah. All right. So let's get into the meta-analysis results.

Research Findings on Exercise Intensity

00:54:21
Speaker
This is the part two of the two-parter. And here's how we're going to do it. First, we'll go region by region. So first we'll talk about the lumbar spine. That's your low back vertebrae. Then we'll talk about the femoral neck.
00:54:33
Speaker
The femoral neck is that narrow bridge of bone. that takes you the ball of the femur in the socket to what's called the trochanter, and it's highly fracture prone.
00:54:44
Speaker
And then total hip, which is a region that includes the femoral neck, actually, plus the trochanter and the intertrochanteric areas.
00:54:58
Speaker
um And they look at the femoral neck separately because it's this key fracture site, which is something I learned. um It also can behave differently than the rest of the hip. So we're going to go lumbar spine, femoral neck, total hip.
00:55:10
Speaker
Okay. Then we'll go by intensity. We'll look at how low intensity, moderate intensity, and high intensity interventions performed for these regions.
00:55:23
Speaker
And we'll also look at within those intensity categories, how did impact only Okay. So that's jumps, hops, landings without resistance training.
00:55:34
Speaker
Then we'll look at how resistance training did without impact, just the resistance training part. And then we'll look at combined interventions that brought both resistance and impact training into the intervention.
00:55:47
Speaker
So for each bone region, we're going to answer among impact only, resistance only, and combined programs, which intensity low, moderate, or high performed best.
00:55:58
Speaker
And secondarily, we'll also get to see which intervention of the three, impact only, resistance only, and combined, actually was most effective. All right.
00:56:11
Speaker
Drum roll, please. Okay, we're starting with the lumbar spine. Here we go. yeah So the big broad takeaway is that all intensities favor exercise over the control for the lumbar spine.
00:56:25
Speaker
Okay, so exercise generally is just really good thing to do for your lumbar spine, bone strength. Okay, now let's talk about low intensity. Overall, low intensity interventions were favored over the control. They performed better than the control.
00:56:43
Speaker
However, impact only low intensity was not statistically significant, meaning low intensity impact training only did not outperform the control for the lumbar spine.
00:56:58
Speaker
Low-intensity resistance training only, sans the impact, right, was statistically significant. So low-intensity resistance training did outperform the control.
00:57:13
Speaker
Low-intensity resistance and impact training combined was was not statistically significant. So low intensity resistance and impact did not outperform the control for the lumbar spine.
00:57:28
Speaker
All right. We're still on the lumbar spine. Now we're talking about moderate intensity exercise. Impact only, not statistically significant. Right? It did no better than the control.
00:57:42
Speaker
Resistance training only, yes. It was statistically significant. So moderate intensity resistance training without impact did outperform the control. However, there was a wide confidence interval.
00:57:58
Speaker
What does that mean? It means that we cannot be precise in terms of the size and effect of the intervention due to a wide variability between studies.
00:58:09
Speaker
All right. But it looks like moderate intensity resistance training is statistically significant. It outperforms the control.
00:58:18
Speaker
I just want to go back. And if you heard confidence interval and got sick to your stomach.
00:58:25
Speaker
Or just confused. A confidence interval in a graph in a forest plot is basically a line, right? And it tells you, like, we're pretty sure the effect, the true effect of this is somewhere between here and here, OK?
00:58:39
Speaker
So if that confidence interval is narrow, like literally narrow, it means the estimate is precise, right? So we like that. Like a dart board, you would see most of the darts clustered around the bullseye, OK?
00:58:54
Speaker
However, if that line is wide, it means that the estimate is fuzzy. That'd be like darts scattered all over the board. The result could be strong, but it also could be weak.
00:59:06
Speaker
And in some cases, there could be no effect at all if it crosses yeah the vertical line, right, showing no statistical significance. So when we say the confidence interval is wide, we're saying that on this forest plot, the line is wide, right? And therefore, we don't have a clear picture of how big the effect really is It could be weak. It could be strong.
00:59:27
Speaker
It could be on the weak end. It could be on the strong end. But what we can know is irrespective of the strength of the effect, it did outperform the control. It was statistically significant.
00:59:40
Speaker
So for moderate resistance training only, yes, it was statistically significant. For moderate resistance training plus impact combined, it was also statistically significant.
00:59:53
Speaker
Okay, so now we're talking about the lumbar spine still. Now we're going to talk about high-intensity interventions. So interestingly, high-intensity impact-only interventions were not statistically significant.
01:00:09
Speaker
They did not outperform the control. which I find surprising, but there's very few trials. High resistance training only was statistically significant, but there was a wide confidence interval.
01:00:24
Speaker
And this is because of an imprecise understanding of effect size due to so few studies. So with the moderate, it was because of a widespread, ah heterogeneity.
01:00:37
Speaker
For the high, it was because a paucity of studies were evaluated. And then when we look at high intensity resistance plus impact training, we also see, yes, it was statistically significant. Again, the confidence interval was wide because of so few studies.
01:00:55
Speaker
OK, so that was the lumbar spine. Now we'll move on to the femoral neck. The authors would like us to know that for low intensity exercise, it did favor exercise over the control, right?
01:01:09
Speaker
Something's better than nothing for sure. They also wanted us to know that there were signs of publication bias at the femoral neck. So results with the low intensity exercise should be interpreted with some caution. OK, so for low intensity impact only,
01:01:24
Speaker
It was found to be not statistically significant. It did not outperform the control. Low-intensity resistance training was statistically significant, and it was the only exercise intervention type in the low-intensity category that did outperform the control because low-intensity resistance plus impact training was not statistically significant.
01:01:50
Speaker
Okay, the femoral neck. Moderate intensity exercise interventions, again, exercise was favored over the control overall. Impact only, though, was not statistically significant.
01:02:03
Speaker
While resistance training alone was, but again, we had a wide confidence interval. We have an imprecise understanding of the effect size because of, again, that wide variability between studies, which is something we see with the moderate intensity exercise category in general.
01:02:20
Speaker
And then moderate intensity resistance plus impact training was also statistically significant. OK. And then finally, high. None of the high intensity exercise interventions were statistically significant.
01:02:36
Speaker
Not the impact only, not the resistance training only, and not the resistance training plus impact for the femoral neck. However, and this I found very interesting,
01:02:49
Speaker
high intensity exercise was still favored over the control. So was still better to do that exercise than to do whatever the controls were doing. um But again, here, the competence interval was wide because we can't be precise because there's just hardly any studies to go on.
01:03:05
Speaker
And found it very interesting that high intensity exercise was generally favored, but that none of the subgroups could show statistical significance. And so I looked into it, and I guess the overall statistical analysis could suggest that high-intensity exercise helps the femoral neck, but when you broke it down with the studies that were included in this paper, splitting the data like that made each group too small and too imprecise.
01:03:36
Speaker
So there's a trend, but there isn't real certainty. Okay, and then for the total hip. For low-intensity exercise, for the total hip, it was not statistically significant whether exercise was favored over the control.
01:03:54
Speaker
And also, none of the subgroups were so found to be statistically significant. So neither impact, resistance training, or resistance and impact. For moderate, it was favored. Moderate intensity exercise was favored over the control.
01:04:10
Speaker
Moderate intensity impact only was not statistically significant, though. However, moderate resistance training only was barely statistically significant and moderate resistance training plus impact was statistically significant.
01:04:24
Speaker
And then for high intensity, we didn't even see a forest plot for this one because there was just insufficient data for the total hip.
01:04:34
Speaker
Whew. How's everybody doing? yeah Are we hanging in? Are we hanging in? ah Here are some takeaways. Yeah, can you summarize all that stuff you just said? Yes. Here's the TLDR.
01:04:46
Speaker
The strongest single subgroup in terms of intensities was moderate intensity. Resistance only. You know, resistance training only.
01:04:58
Speaker
Across all intensities, impact only was not significant, which makes you question whether it's necessary. And high intensity resistance training looks to noticeably outperform other intensities for the lumbar spine.
01:05:16
Speaker
But we're going to look at why it's not so easy to say that either. Yeah. Okay. Okay. Now that you have survived that, I'm going to make you have to survive something else. Hopefully.
01:05:31
Speaker
Yeah. I mean, look. Here's the thing. If Laurel and I are going to make an entire podcast episode about clarifying our message, you better believe.
01:05:46
Speaker
that we're bringing the entire encyclopedia and we are not going to cliff notes maybe pause, get something to drink. If you get a snack, stand up, stretch a little bit.
01:05:59
Speaker
Hopefully you're like taking a walk. That would be a good one to do this one because a nice long walk. And listen, you might need something a little stronger than all of those things. If you need a beer or some plant-based health supplements,
01:06:14
Speaker
Who am I to judge? Okay. So we're going to talk about another statistical component here. And it's something called a meta regression, right?
01:06:27
Speaker
Hang in. We can, we can do this. I believe in us. Okay. So a meta analysis, right? One half of what this whole study was, the meta analysis tells us the overall effect of exercise on bone density.
01:06:42
Speaker
A meta regression takes it one step further and it tries to explain why the results differ across different studies. So it's like asking, does higher intensity actually give more benefit than moderate?
01:06:59
Speaker
And it's a tool for spotting patterns in how certain study features might influence the outcome. So in this paper, the authors ran a meta regression to test questions like this, but they wrote that the findings were not informative.
01:07:17
Speaker
which just means that the data wasn't solid enough to draw real insights. There weren't enough high-quality trials in each category. The studies varied a lot in how they were designed and measured outcomes.
01:07:29
Speaker
The results were just too noisy, right? A little too all over the place, perhaps. So the regression didn't add anything beyond what the main meta-analysis had already showed. So a meta-aggression is optional, right? It's only done if the authors think that they have enough studies with enough variation across them to test whether certain factors like intensity, duration, age group, sex, baseline bone density, explain differences in results.
01:07:58
Speaker
If you don't have enough studies or if the studies are too inconsistent, you can't run the regression. Or if you do run it, the results aren't meaningful. So what the meta regression found was that there was no clear relationship between the percentage of 1RM of the intensity and bone mineral density changes at the lumbar spine or the femoral neck.
01:08:25
Speaker
Right. And that actually directly contradicts the subgroup analysis finding that heavy is best for the lumbar spine because they're saying there's no clear relationship between percentage of 1RM and BMD changes to the lumbar spine.
01:08:38
Speaker
So that's interesting. They also found that in low intensity trials, the older age slightly blunted the femoral neck gains, and that wasn't seen at moderate intensity.
01:08:50
Speaker
And I just want to break in. i i There's one study that they included that suggested that possibly the older you are, the higher intensity you need, which I thought was really interesting.
01:09:03
Speaker
yeah So they found that older age blunted the femoral neck gains with low intensity. We didn't see that at moderate intensity. So a higher baseline bone mineral density, meaning you started out with a higher bone mineral density,
01:09:16
Speaker
was weakly linked to bigger total hip gains at moderate intensity, but because it was a weak link, that might just be a chance finding. They also found that calcium intake and bone density medication didn't consistently change the outcomes.
01:09:31
Speaker
The medication might add a small benefit at the femoral neck, but the evidence is limited. Yeah. Well, we've hinted at this a couple times. Here's where it got a little confusing for me because I first read the systematic review and I fine-tooth combed it covered a cover to cover. And I was like, oh, I think I understand what the takeaway is here.
01:09:50
Speaker
Great. Because in the systematic review, the authors sound very confident about a couple of things. Very confident that low intensity doesn't help bone. And very confident that the best evidence points to high intensity resistance plus impact as most beneficial.
01:10:10
Speaker
But then I read the meta-analysis. And when you flip to the meta-analysis, the actual pooled numbers, that story kind of falls apart. High intensity plus impact doesn't come out statistically better than the other groups.
01:10:25
Speaker
So why the mismatch? Well, there could be two things going on. First, there just weren't many high intensity trials. This makes the evidence shaky. Second, the ones that did exist were kind of all over the place in design and quality.
01:10:41
Speaker
So the same authors wearing their narrative hat for the systematic review could point to promising patterns in a handful of stronger studies.
01:10:52
Speaker
But then once they had their stats hat on and pooled everything, the clear edge for high intensity plus impact training kind of disappeared. And so that's why the results in part one and two look contradictory. The review, the first part, leans toward high is best, especially with impact.
01:11:10
Speaker
The meta-analysis shows a more mixed picture. Resistance training appears to work across intensities, and impact alone is weak. Combined isn't clearly better than resistance by itself.
01:11:24
Speaker
Moderate intensity actually comes out as the most consistently effective across sites. Low helps the spine and neck, but not the hip. High might help, but the data's too thin to say.
01:11:37
Speaker
So in the end, theory and narrative pointed one way, but the pooled numbers couldn't fully back it up. Something else we need to revisit is the difference between statistical significance and clinical significance.
01:11:54
Speaker
So statistical, that's also so hard to say. Statistical significance. it really is. Should be our vocal warmup.
01:12:02
Speaker
Statistical significance. Statistical significance. Right, right. Already on number two, you're making it up. It's hard. All right, here we go. Statistical significance tells you whether an observed effect is likely due to the intervention and not just random chance.
01:12:19
Speaker
And it is determined by things like the effect size, the variability in the data, how many people were in the study, In a meta-analysis, if a confidence interval does not cross the no effect lines the vertical line, the result is statistically significant.
01:12:39
Speaker
Clinical significance is a different question. And this question is, is the size of the change large enough to matter in real life? So for bone, that might mean, will this change meaningfully lower fracture risk or improve quality of life?
01:12:56
Speaker
So a result can be statistically significant, but clinically trivial, especially if it comes from a very large data set where even tiny differences are unlikely to be due to chance.
01:13:09
Speaker
Conversely, a result can be clinically important, but fail to reach statistical significance if the study is too small to detect it. So in the context of this paper, clinical significance would mean asking whether the bone mineral density changes seen are big enough to reduce fracture risk in a meaningful way.
01:13:34
Speaker
Now, there's no universal threshold number for that, but many osteoporosis trials treat roughly two to 4% of a bone mineral density change as meaningful for fracture risk reduction.
01:13:49
Speaker
So Liftmore saw a 3% improvement to the lumbar spine, which is right in the middle of that. Exactly. So clinically significant. Yes.
01:13:59
Speaker
Here in the meta-analysis and systematic review, most gains were smaller. So even if they were statistically significant, they may not cross the clinical significance threshold.
01:14:13
Speaker
And that is important because the forest plots don't actually show one intensity category blowing the others away. In many cases, the confidence intervals overlap, right? So on a forest plot, it means the horizontal the span of the confidence interval overlaps.
01:14:32
Speaker
which means we can't say with statistical certainty that one is better than another. And even where differences appear, the changes in the bone mineral density are small enough that their clinical relevance is debatable.
01:14:47
Speaker
And, you know, we're going to keep kicking this kicker. Only about 6% of the programs in this review used actually high load, over 80% 1RM, or high impact, over four times body weight conditions.
01:15:03
Speaker
And yet, despite longstanding fears about injury in this population, the data showed that serious injuries were rare and most adverse effects were mild. And yet again, we have to repeat it, more studies are needed.
01:15:16
Speaker
Yeah.

Call for More High-Intensity Training Research

01:15:17
Speaker
Yeah, so this review reinforces that we need more randomized control trials looking at high intensity for postmenopausal women. We need randomized control trials putting clearly defined intensities like this paper beautifully did head to head.
01:15:33
Speaker
Personally, I would like to see moderate versus low or moderate versus high. And these need to last for more than six months. I mean, ideally, it'd be amazing if they could last a year or more, as many as possible.
01:15:47
Speaker
less resources and patience of the study subjects. Yeah, I mean, I was going to say, this is like we're living in an ideal world where you can just snap your fingers and make the research that you want to make. Yeah. Real life.
01:15:59
Speaker
gets so lifey in in research as well, not just in your life, right? So it's, it's I mean, yes, it would be so ideal to see what you're talking about. if real It's also incredibly hard to do. Yeah, it is monumental, right.
01:16:12
Speaker
um Another thing to mention is that this paper If we haven't hinted at it already, it certainly complicates the lift heavy shit narrative, especially for hip bone health. But I think it's also accurate to say from this paper that low intensity does not appear to be as helpful as moderate, certainly.
01:16:32
Speaker
Yeah. And also to note, we've said this, some of what the paper calls resistance training only isn't necessarily what most of us mean. That's not how resistance training is broadly defined, right? The paper included formats like mat pilates, tai chi, qigong.
01:16:48
Speaker
And these don't typically apply progressive overload, which is the hallmark of resistance training. My guess is that these low load non-progressive formats specifically will not hold up against higher, so moderate and high intensity resistance training once more trials are available. However,
01:17:10
Speaker
low load resistance training might. And in fact, I think there are studies showing that it that it can. Because if you push low load resistance training close enough to failure within a set, recruitment is high.
01:17:26
Speaker
Forces are very high. And low load resistance training is systematically progressively overloaded. That's why I'd like to see future studies featuring Effort at the end of the set more prominently, RIR, reps and reserve, as a parameter, since it seems to come down to the fact that the set is challenging, not maybe as much what percentage of 1RM we're working at.
01:17:55
Speaker
So since training closer to failure is what might be required for these lighter loads to stimulate muscle and then also bone more effectively,
01:18:06
Speaker
shouldn't we be really zeroing in on RIR or RPE? I just don't see any of that. And granted, my my experience reading research is very limited, but I haven't really seen that parameter highlighted as much as like percent of a 1RM.
01:18:23
Speaker
My understanding is that for strength gains as well, and I think this is interesting, and it's one of the reasons Sarah and i we we see this as an advantage of lifting heavy, that lifting heavy loads, you know, it's stimulating and it produces the changes we're looking for. And you don't actually have to get as close to failure as you do for moderate and then especially light loads.
01:18:46
Speaker
So another question I have, of course, if I could just snap my fingers and have the research happen is like, I would love to see ah ah a randomized controlled trial that somehow was able to look at RIR and compare leaving more versus fewer reps in reserve for varying intensities.
01:19:05
Speaker
Well, you know what this means. to give me money? Yeah, I was going to say, you know what this means. Maybe give me money and then I'll find some scientists to fund that research. No, i was like, we do it. Give us money and we'll do it. Yeah, give us money.
01:19:17
Speaker
Give us money. then just don't worry about it. Listen, don't worry about it. Just don't worry. Your money's in great hands.
01:19:25
Speaker
All right. We got to talk about this Instagram post. Yep. By Professor Phillips. Okay. So as we said, we found out about this paper that we've just spent quite a bit of time telling you about that may have resulted in you needing a lot of support. Yeah.
01:19:42
Speaker
support beverages, support foods, support activities to like make it through. like we found out about this because of a post that we received in our DMs and our emails on Instagram that he made. He also shared it to Facebook.
01:19:57
Speaker
So this is Dr. Stuart Phillips out of McMaster University in Canada. Dr. Stuart Phillips is a distinguished university professor in the Department of Kinesiology at McMaster University in Canada, where he holds a tier one Canada research chair in skeletal muscle health and aging.
01:20:15
Speaker
He directs both the McMaster Center for Nutrition, Exercise and Health Research and the Physical Activity Center of Excellence. With over 400 published scientific papers, he is one of the most cited researchers in the world and a leading authority on how exercise and nutrition shape muscle, bone and healthy aging.
01:20:34
Speaker
His lab's work has been especially influential in showing that muscle hypertrophy can be achieved across a wide range of loads as long as training is taken close to failure.
01:20:45
Speaker
This was landmark research at the time because it challenged the long-held belief that only heavy lifting built muscle. So, I found out he was behind a lot of that research.
01:20:56
Speaker
That's so cool. Yeah, it's awesome. This research research also ended up clarifying that actually heavier loads remain superior for building strength, which is ah common performance goal for people who lift weights.
01:21:10
Speaker
Okay. Now we'd like to play a few clips from this post, which was, I think, just shy of three minutes long. We're going to link, of course, the post in the show notes for you to listen to. And we really encourage you to listen to it.
01:21:23
Speaker
You are going to hear just a short clip of Dr. Phillips summarizing his takeaway from the paper. So before we play the first clip, he starts by introducing the Kistler-Fischbacher systematic review and meta-analysis scene outlines how it categorizes exercise intensity,
01:21:39
Speaker
He walks through one of the paper's force plots and the meta-analysis to illustrate how the results are presented. Also, want to add, he's doing something that is very difficult to do, which he's simplifying a complex analysis for a general audience in less than three minutes.
01:21:53
Speaker
So I just want to like give you a heads up. What I hear him saying in the entire clip is we don't have evidence that heavier is always better. Moderate loads are the most consistently effective in the current data.
01:22:05
Speaker
People have options, right? He's saying you don't have to lift at 85% to 90% of your max, aka heavy, to benefit your bones. Please do listen to the full post. So here's here's the first clip.
01:22:18
Speaker
This is the force plot for the lumbar spine. These are the individual trials and you can see that there's lots of them here and the the diamond here represents the net aggregate result of all of those trials. So here's low intensity, moderate and high, and this is the overall effect. So the good news is just de about everything favors exercise, including low, moderate, high and the overall effect. And so It's great news. Exercise affects lumbar, spine, bone mineral density, but all intensities were equivalent.
01:22:50
Speaker
Okay. So Phillips says all intensities are equivalent in the video, but here's what I think it's really important to understand that just because there were not statistically significant differences between the interventions, according to the meta-analysis, that's not the same as saying they're equally effective.
01:23:12
Speaker
which is what people might hear when they hear him say all intensities are equivalent. All intensities are equivalent just means that the data we have didn't show one intensity clearly outperforming the other.
01:23:25
Speaker
And the fact that that's what the data shows could mean a couple of things. It could mean that maybe they really do perform similarly, or it could mean that maybe there just weren't enough trials, especially in the high intensity group to detect a real difference.
01:23:45
Speaker
So where I get concerned, right, because of our familiarity with the demographic that we serve, which is women from age 40 to 70, roughly, is that when people hear all intensities were equivalent, they're going to take it to mean that all intensities work equally well.
01:24:04
Speaker
But that's not what this paper actually suggests. It is true that all intensities can help bone. Right. In the same way that we can say something is better than nothing when it comes to exercise.
01:24:18
Speaker
It's the I came first in the race compared to I finished the race. Right. Both are true. So you might just say, oh, well, then both are the same.
01:24:31
Speaker
but they're not the same. One was better than the other, right? Both can be true, but both may not be the same. So the most consistent improvements across the skeletal sites in this meta-analysis were seen with moderate loads.
01:24:45
Speaker
Low intensity improved lumbar spine bone mineral density, but showed no significant effect at the hip or the femoral neck. High intensity improved lumbar spine bone mineral density, but the evidence base was so small that we can't be confident about whether it truly performs as well, better, or worse than moderate at the other sites.
01:25:06
Speaker
So in short, moderate is most consistently effective across sites. Low has lumbar spine only benefits. There's risk of publication bias for the femoral neck.
01:25:18
Speaker
And high is promising for the spine, but it is under-researched for the other sites. I think Phillips is really trying to dispel the idea that it has to be one way, which is what he does, which is needed, right?
01:25:30
Speaker
Yeah. It doesn't have to be heavy or high. He then continues to walk us through the forest plots for each site. He also points out that the one fracture risk trial in the analysis favored exercise but it wasn't a high intensity program. So you're gonna hear him mention that trial and we'll talk a little bit about it. So here's the second clip.
01:25:56
Speaker
This is the femoral neck. You can see it works for low, moderate, actually doesn't work for high, although there's not a lot of trials in this area, but the net effect is that exercise is good for the femoral neck. This is the bone that a lot of women break or men,
01:26:12
Speaker
when they fall and obviously it's associated with long-term morbidity and mortality. This is total hip. The low actually didn't quite cut it. Moderate did and high did not, although there's only one trial in this category.
01:26:28
Speaker
Interestingly enough, and this is I think the important part, when we talk about um the effect on fracture risk, it is favoring exercise, but there's only one trial in here that is significant and this is by Korpelainen and it's a Finnish group.
01:26:44
Speaker
And the interesting part is when you look at this intervention, it's actually not high intensity exercise. So the conclusion is is that many types of exercise or lifting intensity work to enhance bone mineral density at various sites. However, the data are actually most consistent for moderate 65 to 80 percent of ah rather than higher loads, but many loading patterns work.
01:27:07
Speaker
Obviously, you need to do more work, but fracture risk was significantly reduced only in one study, but exercise in general was beneficial. I hope that serves to clarify why you don't need to lift heavier weights.
01:27:21
Speaker
Okay. So Phillips is distilling a lot of nuanced data into a simple public message. Most kinds of exercise Lifting impact can help bone.
01:27:35
Speaker
Moderate loads show the most consistent results across the available trials, and you don't have to lift at highest intensities to benefit. That's a really helpful message from an accessibility standpoint.
01:27:47
Speaker
But I think it's also important to emphasize that while, yes, the review shows some benefit at all intensities for certain sites, not all intensities worked equally well across all sites.
01:28:00
Speaker
Yeah. He then also points out that fracture risk reduction, arguably the most important real-world outcome that we are going for, was seen in just one trial, and it wasn't high intensity. So I pulled this paper. Thanks, Naomi.
01:28:20
Speaker
The corpuline in paper was very interesting. One thing found, and it's not our area, but one thing it found was that improvements to bone mineral density were statistically significantly associated with increases in body mass.
01:28:39
Speaker
Oh, that's interesting. Which is, and also it is something that we don't probably say enough, right? Yes. Diet is such a huge part of this.
01:28:50
Speaker
Yeah. yeah Of note as well, the authors themselves wrote, quote, our data suggest that the chosen regimen might be effective in reducing falls and fractures, but the sample size was not large enough for these outcomes, and no definite conclusions can be drawn from this data.
01:29:11
Speaker
So while the Korbalainen paper did look at fracture risk reduction, they admit that they probably didn't have enough data to go on to make firm conclusions about their intervention and its efficacy for that outcome.
01:29:29
Speaker
I also don't know that the trials that this systematic review with meta-analysis looked at were actually assessing fracture risk prevention, right? right This particular trial was, right and Phillips highlights it.
01:29:45
Speaker
Yeah. And I think why he's highlighting it is that it has great clinical relevance, right? Like, this is what we're trying to actually do, which is prevent fracture. The bone marrow density improvements are a road to that destination, right?
01:30:01
Speaker
Yes. And this was, he's making the point, a moderate intensity intervention that did that real world significant thing. I thought, you know, that was worth mentioning.
01:30:12
Speaker
Yeah, definitely. So just to kind of summarize, while we agree with his, you don't have to lift heavy for bone density benefits, that's his conclusion.
01:30:26
Speaker
We agree with it so much, we're changing our message. What he isn't saying is that heavier loads offer no benefit or even no added benefit. It's just that there isn't enough evidence on high-intensity interventions on this population of post-menopausal women to be able to say that.
01:30:44
Speaker
So all exercise is better than none for bone health in post-menopausal women. That's always going to be true. Low intensity rarely produces meaningful changes, even in the higher quality trials.
01:30:58
Speaker
Moderate and high intensity both work and their results often overlap. High intensity might be the best for the lumbar spine. Moderate intensity might be the best for the total hip, but evidence is really limited, especially for the real, true high intensity work.
01:31:18
Speaker
I'm gonna say it again, more studies are needed. The biggest gap right now is the lack of high intensity research in this population. That is not proof that high is either superior or unnecessary, right? It's just that we don't have enough evidence to make either of those claims really, really confidently.
01:31:39
Speaker
And one more time, more studies are needed. All right. So back to Philip's post. We found out about this sometime in April. A lot of you were, you know, sending us messages about it.
01:31:51
Speaker
I watched it and then I just was like, I can't get into this right now because this is going to be a thing. Like I knew when I got the post, this is going to be a whole thing. Yeah. Because this seems very credible. And no, I was not aware of this systematic review with meta-analysis.
01:32:06
Speaker
So we got to read that and we got to look at this, right? But then i you know, at some point went back to his post and I asked him a question and then he never responded. And then I was like, oh, you know, I'll DM him because i'm this was like from months ago and now I'm asking him a question and he's a busy guy.
01:32:22
Speaker
So then... I went back again and I found another post that he had made. It was the same post, but he put like a better image on it. So it got more views. And I asked the question again. I was like, why can't I find my question? And then I was like, I don't know. I'll just ask it again.
01:32:37
Speaker
And I saw that someone had tagged us in that post and I had never seen it. And it was like eight weeks in the past. and i was like, oh, this person has tagged us. So this is a listener of our podcast who tagged us.
01:32:48
Speaker
And here's what they wrote. I have listened to several of your podcasts, including the one with Belinda Beck, and thought this post might interest you. It's a relief to learn that lifting heavy isn't the only route to bone health and density.
01:33:04
Speaker
And then again, Professor Phillips probably replied to her pretty quickly and wrote, this very recent network meta-analysis provides the most up-to-date analysis and uses networks.
01:33:15
Speaker
I've included it in the caption, and you can see their conclusions. It's not at odds with Dr. Beck's interpretation, but it's far broader than the lift-heavy shit narrative and certainly would provide at MovementLogicTutorials listeners with a broader menu of options exercise-wise to improve bone health.
01:33:36
Speaker
Remember, bone mineral density is related to fracture risk, but the trial that showed a significant reduction included no heavy lifting at all.

Listener Engagement and Influence of Discussion

01:33:46
Speaker
Again, I'm going to interject and say, yes, the corpulonin trial is the one he's referring to.
01:33:51
Speaker
As we stated earlier, the authors of the paper wrote, no definite conclusions could be drawn from this data. So I responded to this person, the listener to our podcast who initially tagged us, and I wrote, oh, this one slipped through the cracks. Thanks for tagging us. Agreed that it is good to know and ultimately very good news.
01:34:09
Speaker
At Movement Logic, we have adjusted our message in light of this new information. Our course has always included all intensities in both resistance training and impact training because it's illogical to only offer high intensity from a principled standpoint.
01:34:22
Speaker
None of the principles of variety, progressive overload, or individuality support a high-impact or high-load-only approach. I've read this meta-analysis and systematic review.
01:34:33
Speaker
I should have said systematic review. By the way, at this point when I'm writing this, I had only read the systematic review. I had not yet read the meta-analysis. I think that based on it's clear that heavy resistance training is best for the lumbar spine. Moderate appears most effective for the hip.
01:34:47
Speaker
It's very clear that more research is needed as of the 120 included papers, only six looked at high intensity resistance training. I think what LiftMore did for us more than anything is showed that high intensity resistance training is safe, even for postmenopausal women with a history of fracture.
01:35:02
Speaker
Hopefully we will get more nine month plus um RCTs comparing high and moderate intensity exercise. Additionally, I think it's worth pointing out But according to part one, the meta-analysis, I mixed that up.
01:35:13
Speaker
It was part one, the systematic review of this paper. The research on low-intensity exercise was of the lowest quality, highest risk of bias, according to the authors, even though the forest plot in part two does not convey this.
01:35:25
Speaker
All exercise is good. Something is better than nothing. But it does appear that there is some specificity at play here. which is to be expected for bone just like it is for muscle and soft tissue.
01:35:36
Speaker
More studies are needed. We're going to do an episode about this paper and some of the trials it included in September. At some point, we'd love to bring on at Mac and Prof. That's Dr. Phillips' tag as well.
01:35:49
Speaker
All right, so in early June, as I said, I wrote to Professor Phillips asking why, you know, in in the comment on this post, why the systematic review summary of low-intensity exercise seemed so negative when the forest plot looked more positive. This is just a summary of what I wrote. The review stated that low intensity exercise generally had little to no effect on bone marrow density and that the overall message was that higher quality evidence points to a low intensity exercise being ineffective for improving bone marrow density at the main fracture prone regions.
01:36:19
Speaker
And I'm responding to when he says all intensities are equivalent in the video, right? And he responded graciously. Agree with all your points here and above.
01:36:30
Speaker
If the quality of the data are important, then I think the message is clear, as you suggest. However, and importantly, Dr. Beck runs a business based on results of Liftmore, and so leans heavily on the heaviest best, and has appeared on several podcasts saying it's the only way to improve bone mural density.
01:36:49
Speaker
Clearly, the evidence is more nuanced. Bones tend to improve with impact also, which I'd argue is not high intensity exercise, but a category unto itself. Okay.
01:37:01
Speaker
So a couple of things. One, he responded to us weeks, months after he made this post. So that was that was generous of him. The Kistler-Fischbacher paper does define intensities for impact exercise.
01:37:13
Speaker
So it can be classified in terms of intensity to be low, moderate, high. You can also progressively overload impact exercises like plyometrics. You know, it can be experienced and measured at different intensities, but it's very practically difficult to measure this.
01:37:29
Speaker
So, you know, it's fuzzy. the The authors sat down, they talked about each study, and they were like, this one seems moderate, this one seems high. The other thing I want to discuss is how he seems to be suggesting Beck has bias due to her O'Nero program.
01:37:43
Speaker
And we also had a lengthy DM exchange with another exercise scientist expressing the same concern for Bex Bias. what do you think about that? I very much don't want to be casting aspersions on anybody.
01:37:55
Speaker
So I don't want to be coming on here and being like, well, yeah, she only thinks it's this because that's her program and she has a vested interest.

Bias and Interpretation in Exercise Science

01:38:05
Speaker
While all those things are true, you you know, her Onero program, from what I understand, basically follows the same exercise protocols as Liftmore, give or take, right?
01:38:18
Speaker
So yes, that is what she is doing. I just really don't want to be out here suggesting that somebody is behaving in an unethical manner because of where their income source is. Yeah, yeah. And I mean, I think science is very interested in bias.
01:38:34
Speaker
I mean, it is laser focused on it, right? And I think what's being pointed out here is that there is this potential bias, right? Yeah. But I think the other thing, though, is always like it's impossible to have no bias.
01:38:46
Speaker
all still human beings wandering around with our own human biases. Correct. And I would say that it's harder to not have bias when you sell a program. Sure. like It was hard for us to come on air and be like, we were wrong.
01:39:00
Speaker
Because we sell a program. Thank God we don't have to change it at all. Do you think we would have had a harder time changing our message if our entire course was somehow going to be rendered irrelevant with this new discovery that it didn't have to be heavy? Because maybe we did fully model our course off of Lipmore, by the way, which would have been unethical because that's copying and pasting. yeah but like But I mean, what if we had just decided, no, only heavy. It's all heavy. It's heavy from day one. you know and then, and now oh my God, now...
01:39:30
Speaker
Right. Yeah. Look, I think it would have been a lot harder, but ah what I would have felt is just very bad that we had already put people through this terrible, heavy only lifting course, which it never did because that's insane.
01:39:46
Speaker
Yeah. So, okay. I responded to Phillip's comment. Movement logic tutorials might be able to offer a wider array of exercise options. I was like, yes, we already do. So my response to him was like, to be clear, our message also used to be that heavy is best for bone building because that is what we believed was true. This, despite having a program that included and still includes all intensities, because how else are you going to get beginners to lift heavy? We have since changed our message. Our, our program is largely the same though.
01:40:16
Speaker
And indeed, we were and still are very inspired by Dr. Beck's work with postmenopausal women with a history of fracture and her willingness to try the third rail of exercise on them to then happily discover that actually they could handle it and benefit from it.
01:40:30
Speaker
But we also knew that we didn't want to create a program for people that only included three to four exercises, only included high intensity loads, and for which the single impact exercise was a stiff-legged landing from a pull-up bar.
01:40:42
Speaker
Not that you can't make that type of exercise fun and enjoyable for women age 40 to 80. I'm sure you can, since it's often human connection that makes most exercise enjoyable, but because several of our other goals did not require such a rigid adherence to such a small array of strength and impact exercises.
01:41:01
Speaker
These goals were, in addition to building bone, to, one, elevate students' baseline of strength, which we knew we could do across all load intensities. Two, provide strength training education, give students the fishing pole, not just the fish, which would involve understanding what low, moderate, and high intensities are and exploring all three.
01:41:17
Speaker
And three, to introduce them to power and impact training, applying the principle of progressive overload. Students gradually increase both intensity and volume of the impact plyometric exercises in our program and are given tools for wear along the spectrum of low to high intensity and volume they individually should start.
01:41:36
Speaker
Overall, I think what we've learned is that women can lift heavy. They can enjoy it, and it can be very empowering for them. Our message now

Empowerment and Overcoming Societal Bias in Fitness

01:41:46
Speaker
is that you don't need to lift heavy, but you also don't need to be afraid of lifting heavy.
01:41:51
Speaker
In fact, let's examine all the reasons you as women have potentially been discouraged from lifting heavy. And let's examine if perhaps the act of lifting heavy doesn't in some untestable way, probably, leave you feeling lighter, sloughing off and a fucking off of the patriarchy, if you will.
01:42:09
Speaker
And that was my comment to him. Didn't respond to that one. I think she was like, that is a long comment. I am busy. you like Wow. This, this lady, she sure likes to leave long comments. That, that happens to me a lot, by the way. Yes.
01:42:20
Speaker
I just want to say about Onero. My understanding is that, cause I just remembered it is, it is modeled off of lift more, but they are also including components of what they're calling balance training and other types of exercise as well. So it's not just lift more.
01:42:35
Speaker
Yeah. Okay, cool. Yeah. So. I, when I first saw the message that Dr. Phillips was espousing, I was concerned about how it was going to play out. And it kind of, for some people, played out exactly the way that I hoped that it wouldn't.
01:42:51
Speaker
Yeah. Which was, there were a lot of people saying things like, phew, there are lots of women who can't lift heavy. So glad to hear they don't have to. And, ugh. The thing is, but while I do appreciate his work, we can't think about exercise for women in a vacuum.
01:43:09
Speaker
We just can't because it's always forced to fit into the story about how women should exercise inside of a patriarchy. And the emphasis is always the It's not ladylike to lift heavy. It's too dangerous. There's too much risk of injury.
01:43:25
Speaker
Instead of this is a skill that you can teach your body slowly over time and has value in and of itself. I responded to several of the commenters on his post. i'm just going to read you some of their comments and some of right right back. So one person wrote, and this person was a PT quote, this is very helpful to hear.
01:43:44
Speaker
I work with a lot of women over 60 who have osteoporosis and feel like the only option is to lift super heavy, but they've never touched a weight or are scared to do so. This gives me more options and validation to my clinical practice.
01:43:58
Speaker
And I responded, it's not impossible to create programming that ramps up from light to medium to heavy at any age for any women. And while for their bones, they may not need heavy, that population certainly needs to stay as strong as they possibly can.
01:44:15
Speaker
Let's not completely throw out a valuable aspect of resistance training. So then another person wrote, I think at McEnprof and his group are making exercise guidelines for women clearer, simpler, and therefore much more accessible than other groups that are emphasizing specific protocols that are not as widely applicable to general populations of peri and postmenopausal women.
01:44:38
Speaker
So I wrote back to her, I'm curious what you mean by specific protocols. There's no reason that women of any age cannot access heavier lifting as long as they are taken through a properly thought out and progressive program.
01:44:51
Speaker
I think we need to get away from this idea of, oh, thank God it doesn't need to be heavy because women can't lift heavy. This is an absolute myth. Heavy is relative. It depends on the individual.
01:45:02
Speaker
And it's a capacity that older women benefit from in a myriad of ways. And then she responded back to that. Of course, heavy is relative, but lifting six reps and under requires progressive training as isn't something women with minimal lifting experience should start with, which is, she's just repeating what I said.
01:45:19
Speaker
Many need to build that capacity to do so safely and effectively, which is also what I said. And in many cases, that requires coaching and supervision, which many women don't have access to. And then in parentheses, she put $2 signs.
01:45:32
Speaker
And I thought it was interesting because I think this person is a personal trainer. So I'm like, well, you're saying they have access to you and some things, but then suddenly this is like out of the question, exorbitantly expensive, which spoiler it's not.
01:45:44
Speaker
Also, you don't absolutely need coaching to learn how to lift heavy. i mean, you don't. you know Some people will really benefit from it. Sure. But I think it's a stretch to say that if you want to lift heavy, this requires you to have a personal trainer or to receive individualized coaching.
01:46:00
Speaker
I started lifting heavy, and this is N of one, and I'm not using this as proof, but I'm just saying it's not necessary because I didn't. I started lifting heavy without a coach. Sure. I mean, if you I would say it depends on the person.
01:46:12
Speaker
I benefited enormously from getting a coach, but but you also And you also came from a background of movement already. Like you had a very good sense of your own body. And I'm not injury prone. The part that I sort of questioned is this idea that it was the money that was stopping people from getting to coaching and supervision. There is so much free content out there. there is Gym memberships are not expensive. you know Anyway.
01:46:35
Speaker
Right. i think you're going to make this point too, which is that I don't know that there's conclusive evidence that lifting heavy is more dangerous actually either than lifting light. So she goes on to say, it's important to reassure women Ugh.
01:46:47
Speaker
I just fucking hate the idea we have to reassure people. m Like, no, I think it's important to inspire confidence in women. Not to their their women. Anyway, it is important to reassure women that they can still derive benefit to bone and muscles using different types of protocols, i.e. program design.
01:47:05
Speaker
This isn't the same as saying women shouldn't lift heavy. I coach all kinds of women with all kinds of abilities and all kinds of resources and limitations they can all train for benefit. I mean, I just found that comment a bit like weird and self-contradictory. But anyway, and then I said, agreed on all points. I'm just saying that heavy lifting has been gatekept away from women as something they shouldn't even attempt.
01:47:25
Speaker
And while it's reassuring that you don't need it for bones, though evidence does seem to point to heavy for lumbar spine changes, I'm always thinking about women and exercise in the context of the patriarchy we live in.
01:47:36
Speaker
Women don't have to lift heavy for bone, but that doesn't mean they can't benefit in many other ways, including improving their max strength from heavy lifting. I want to make sure we're not reinforcing the message for women that they can't lift heavy, danger, injury, et cetera, when most of them from a physiological standpoint definitely could.
01:47:55
Speaker
That's all. And then she said she agrees with me. And then someone else said, This opens many doors for midlife women who feel pressure to lift heavy when that's not where they are or are unable to.
01:48:07
Speaker
And honestly, this one made me feel like we've really fucked up the messaging around lifting heavy because nobody starts with heavy. Nobody. So why are there so many people responding about how midlife women can't lift heavy when the real answer is, if they're beginners, of course not, and nobody is asking them to.
01:48:27
Speaker
Why is that suddenly the siren call, right? Don't worry, won't lift heavy. you won't start heavy.
01:48:38
Speaker
yeah Of course you fucking won't. So I responded, since heavy is a relative concept, I think a lot more women actually can be coached in a thoughtful and progressive way to heavy lifting. I don't think it's a useful message to continue to downplay women's potential.
01:48:54
Speaker
or to continue to promote this message that heavy is scary and dangerous when it's something that for the vast majority of women is accessible with good programming. And I wrote, while recognizing that bones don't need heavy weights, that doesn't mean that the rest of your body wouldn't benefit.
01:49:09
Speaker
Yeah. Now, someone else wrote, i have always felt like this lift heavy idea must be a fad.
01:49:24
Speaker
Yep. It's a fad. It's a relatively new, you think she's referring to the LHS movement, right? I mean, sure. But like lifting heavy has been around literally forever. Yeah. it's not a fad. It's not a fad. Yeah. And then they go on to say, I have had injuries trying to do it.
01:49:39
Speaker
Unfortunately, so many, and she put doctors in quotation marks and then influencers in parentheses, pushing this idea, especially to menopausal women. And I responded, lifting heavy is not a fad.
01:49:51
Speaker
And there are still numerous benefits for women at any age. If you injured yourself, it's likely your programming has been incorrect or you did not progressively overload. Heavy lifting is no more dangerous than moderate or light lifting. And while it's definitely great news that lifting any amount of weight is helpful to bone, I am concerned that women are just going to drop the idea that they should even try to lift heavy when it's got so many other benefits.
01:50:16
Speaker
Yeah. I was just thinking of ah another good reel we could create, which is this idea from all these comments that like, oh, thank God women don't have to lift heavy.
01:50:28
Speaker
Yeah. And the irony of that, when you look at women in a yoga class doing chaturanga. Right. Which is a heavy load for a lot of them. And in many cases, a too heavy load. And how when women's or, you know, anybody signs up for their first yoga class,
01:50:45
Speaker
And if it's a vinyasa flow class, and if it's not a beginner class, they're probably going to be doing a ton of chaturangas. Yeah. You know when you start to understand what intensity means and how resistance training works, like yoga is not technically resistance training, but you are having to overcome resistance in yoga. And so most of the loads in yoga are light, but some of them are actually really heavy.
01:51:08
Speaker
And in the case of chaturanga, that is an objectively for many students, heavy load. And I feel like if that was understood, they'd be less afraid of heavy. It's like, you see, you're actually already doing it all the freaking time, you know? like So yeah, heavy is this scary thing. Heavy, lifting heavy weights.
01:51:29
Speaker
Yeah. And it's like, well, you're you you're lifting heavy weights in yoga sometimes. You're lifting heavy weights in your life sometimes. Like, why not get good at it? Right. So that you can do yoga and do your life better, right?
01:51:40
Speaker
Right. All right. So I want to talk a little bit more about Dr. Phillips, his Instagram grid, which by the way, I highly recommend following Dr. Phillips. He's a wonderful source of education.
01:51:51
Speaker
This post in particular kind of stood out to me. It's a single meme in bold text and it says, so few people who offer fitness advice fail to understand or make clear the difference between need and sufficient.
01:52:08
Speaker
There's a big difference between the two. Nobody needs to lift heavy weights for any health-related benefit unless that's a training goal. And in the caption, he wrote, the need to do something means that without, nothing happens and you don't get the benefits.
01:52:28
Speaker
That something is sufficient means that it coexists with something else and the two can be correlated. There's not any health benefit associated with resistance training that doesn't happen when you lift heavy or lighter weights with high effort.
01:52:45
Speaker
You don't need fatigue. You don't need to lift heavy shit unless you want to. Remember, the vast majority of people don't lift weights at all. Let's stop overcomplicating things and remove barriers.
01:52:57
Speaker
And then he writes, no, working out, fed or fasted is also not a big deal. Proteins, yesterday's post, also not a big deal. So I found this to be a very enlightening post.
01:53:08
Speaker
I think it's a very good point. I think it's at the heart of what he's about, which is helping people figure out what they actually need and separating that from the fire hose of garbage online, selling things that are...
01:53:25
Speaker
you know, not going to move the needle much, not evidence-based at all, made up bullshit a lot of the times. And so that's not easy to do, right? And so I think he's serving a very important role as a science educator online.
01:53:41
Speaker
I think we need more people like Dr. Phillips. Definitely. You always like Dr. Colenzo Semple, who are gonna you're going to hear from this season. So Anyway, I thought that was a

Exercise Necessity vs. Sufficiency

01:53:52
Speaker
cool post. And I think that it also summarizes why we are shifting our message, which is that lifting heavy is sufficient for bone building, but it's not necessary, actually. What do you think, Sarah?
01:54:05
Speaker
So, yeah, I mean, this falls under a little bit of the, like, just do something exercise advice, right? The something is better than nothing. And I did a episode about that recently.
01:54:16
Speaker
ah that Laura will link in the show notes for you. Show notes, that's going to... This is a beast of an episode. and yeah There is merit to saying something is better than nothing.
01:54:29
Speaker
And that is proven in evidence around exercise in general. But when we have a message that is that broad, that we lose the impact of the detail, right? When we go in and sort of like take a micro look at different kinds of of exercise and why they might have different kinds of benefit or why you might choose to still do some of them. So It's a wide net, right, to try to grab as many people as possible.
01:54:59
Speaker
And, you know, I think there's questions around whether or not that wide net is a really effective way to go, but we're going to talk about that in a second. So, yeah, when a researcher says you don't have to lift heavy, that's true. What some women hear, as we saw in the comments, is good because it's scary. It's not for me. People can't do it.
01:55:15
Speaker
It's risky, right? And that's where we need, I think, to slow down and unpack where that's coming from. Right. So we're not here to argue against Dr. Phillips. I think we're here to extend the conversation.
01:55:26
Speaker
you know bridge the gap maybe. like We're not sociologists, nor are we scientists really, right but we want to bridge the gap between what's in the research and what actually happens in real life, where there's fear, there's a history of misogyny and inequality, there's social messaging about gender norms, women's bodies, right that women have been experiencing and relating to exercise in a particular way because of And these are all also very real, maybe not as measurable, but they're very real.
01:55:58
Speaker
So we get where he's coming from. Most adults, men and women, aren't strength training. Like 80% of women don't lift weights. Yeah. So this message, any exercise is good for bone. It casts a wide net and he's right.
01:56:10
Speaker
He's right from you know an evidence-based standpoint. It doesn't have to be heavy. where maybe we are diverging or we're just extending the conversation further is twofold, right? First, while participation rates are higher for men, a large percentage of men don't strength train either, but women face an added barrier, which I listed decades of social conditioning, telling them that lifting weights is not for them. It's unsafe. It's too intense. It's unfeminine. They'll get bulky, manly looking and then lose societal value.
01:56:40
Speaker
And that history has left a lasting mark, especially in yoga and Pilates spaces where sometimes the prevailing message is also, this is enough, this covers all the bases, this is all you need.
01:56:54
Speaker
And then second, we don't agree with equating low, moderate, high intensity when it comes to bone outcomes based on this paper. If you look at the data, the low underperforms when compared to moderate or heavy. But back participation rates for women in strength training, I have a bigger question, which Sarah hinted at, which is do broad, nonspecific recommendations actually work to bring women in to spaces where they're underrepresented?
01:57:20
Speaker
Or do bigger shifts happen when the message is specific, bold, and it changes how women see themselves, right? So Is the lift heavy shit potentially an example of that?
01:57:34
Speaker
We don't have a solid answer here. We're not sociologists. Big cultural shifts are complex, right? yeah But history has hinted at a pattern that does stand out with regards to getting more women involved in something perceived as male or male dominated.
01:57:51
Speaker
And that is STEM. Yeah. So STEM, if you're not familiar, stands for science, technology, engineering, mathematics. Is that right?
01:58:02
Speaker
Yeah. I was like, I'm going to say this super confidently and then I'm not sure.
01:58:10
Speaker
So back in the 1990s and early 2000s, a lot of the messaging to get girls into science was friendly, safe, non-threatening. You know, you'd hear things like science is fun.
01:58:20
Speaker
You don't have to be a genius to try it. Something like that. Come on in, dum-dums. No. That approach, it works
01:58:32
Speaker
it works to to spark curiosity, right? More girls dipped a toe into science fairs or afterschool programs or maybe even an elective or two in high school. But it didn't actually close the gap in fields like engineering or physics where women were still vastly underrepresented as a career.
01:58:51
Speaker
Yeah. The bigger change came when the message itself shifted. Instead of just saying science is fun, it became girls can be scientists, girls can be engineers, girls can be astronauts, you belong here.
01:59:08
Speaker
Those words, you belong here, started to rewrite identity, not just ability. They weren't about coaxing you into trying something for fun. They were about claiming that space as yours.
01:59:20
Speaker
And interventions emphasizing identity, such as role models, belonging, culturally affirming pedagogy, have been shown to impact girls' STEM self-concept and continued interest.
01:59:34
Speaker
Studies show that girls' sense of belonging and self-efficacy strongly influence their STEM persistence. Yeah, the same

Inclusion Strategies and Strength Training for Women

01:59:43
Speaker
principles have shown up in sports history too.
01:59:45
Speaker
So for example, marathons. For decades, women weren't allowed to run them officially. In 1966, Bobby Gibb ran the Boston Marathon unofficially, finishing in three hours and 21 minutes.
01:59:57
Speaker
That frigging fast. Faster than two thirds of the men that year. The following year, Catherine Switzer registered with a bib number and was physically attacked mid-race by an official who tried to shove her off the course.
02:00:09
Speaker
She kept running. and probably just a lot faster than he was. And the photos went around the world. Five years later 1972, women were officially allowed to compete in Boston.
02:00:22
Speaker
That's 1972. Okay. And then in 1984, like just a couple, 20 years ago, the women's marathon was in the Olympics. So women weren't allowed to run in the marathon in the Olympics until 1984. Okay.
02:00:35
Speaker
okay Anyway, I'll, I'll move on. that's a called That's a cultural shift. So it started with a tiny group of early adopters, literally a handful of women whose visible participation challenged every norm in the rule book.
02:00:46
Speaker
And over time, that small start changed what was considered normal. Yeah. So I also want to talk about our students in bone density course.
02:00:57
Speaker
Yeah. With their barbell setups in their houses or they're in the gym. Mm-hmm. they're lifting their weights, right? And I wonder what their children, their grandchildren, what their peers think when they see that.
02:01:13
Speaker
yeah I wonder how they are influenced by that, by seeing this person who is their friend or their mother or their grandmother lifting barbells. yeah I wonder what that does to them and their future and the way they think about lifting weights.
02:01:28
Speaker
Right. And even, I mean, I've done a little bit of training with my two twin nephews who are 14, and it's really very much like herding cats. But I think it's cool for them that the person that's teaching them how to use barbells is a woman.
02:01:42
Speaker
Absolutely. It's not not their dad or some guy at the gym or something. It's their aunt. Yes. Okay. yeah So what does this have to do with Dr. Phillips' message and ours? I think his broad message is evidence shows heavy is not necessary for bone health, and he believes it's both inaccurate And intimidating to say that heavy lifting is necessary.
02:02:03
Speaker
And so I think from this message, you would assume, okay, who is he speaking to? Is his audience the broadest possible one? Is he trying to catch the most amount of fish in this broad net, you know, including the roughly 80% of women who aren't strength training at all?
02:02:16
Speaker
And his goal is to pull them in with the lowest possible barrier to entry? Any exercise is good for bone. I think he's just reporting on the research, to be honest. ah But I actually suspect his audience is made up heavily of student clinicians, student scientists, as well as working professionals in this industry, personal trainers, right?
02:02:34
Speaker
And other evidence-based creators and influencers like us. He's the person who tells the people who tell the people what's up, right? He's like a renowned educator of educators, a sports scientist with decades of experience.
02:02:46
Speaker
And we are not. Yet we get where he's coming from. We're on the same team. but we take a slightly different viewpoint and as a result approach. So first of all, we do agree.
02:02:59
Speaker
The evidence for women should always be evidence-based. It doesn't have to be heavy. Overcomplicating exercise is not a good thing for women and creating unnecessary limitations. Like it has to be X or Y or Z is unhelpful.
02:03:14
Speaker
That's why we're changing our message. Where we disagree, is that the idea that low-intensity training is equivalent to moderate or heavy for bone health. The paper he's referencing, in our opinion, does not support that.
02:03:28
Speaker
Secondly, we question whether these broad anything counts messages are actually enough to shift women's participation in strength training, and especially in heavier lifting.
02:03:41
Speaker
But I would say, honestly, probably also to moderate lifting. There's a lot of women that are way more comfortable with a five pound, three pound dumbbell in their Pilates sculpt class. Forever. Forever. Yeah. Yeah, heavy is a direction. It's not just a destination. Right. So even even the moderate that you would right do on the way. Yes, you'd have to go heavier to go moderate from late, right? Yeah, exactly.
02:04:02
Speaker
In this instance in particular, it is too much of a pendulum swing in the opposite direction from lift heavy shit to state that anything counts for bone density, right? As usual, it's just more nuanced than that.
02:04:15
Speaker
So if history is a guide, these big cultural changes where women move into formerly male-dominated spaces often happens when a smaller group of people or a single person makes a radical shift or where gender-affirming messages are deliberately propagated, as in, get in, girls, we're getting fucking jacked.
02:04:35
Speaker
And then their example influences the rest of society. Right. Philip's strategy is like the early STEM message. Just get people in the door, make it non-threatening, get them to try it.
02:04:46
Speaker
Our strategy, possibly because we are women, though who can say, is more like the, I mean, not who can say we are women. Just that whether it's based on because we're women. Right.
02:04:58
Speaker
I know what you meant. It just sounded funny. Yes. I know. I saw. i saw what happened. So our strategy is more like the STEM shift that came later. Make it clear that this space is for you.
02:05:10
Speaker
You belong here. It's not dangerous. It's not for someone else. We're not trying to coax you into any exercise. We're trying to invite you to see yourself as someone who can lift heavy things safely and confidently.
02:05:25
Speaker
Yep. And as we've said, heavy is relative, of course. Yeah. Person to person. Scientifically, high intensity resistance training means a rep range of fewer than eight reps.
02:05:36
Speaker
Sometimes it's defined as fewer than six per set. and if we're talking about impact, greater than four times your body weight, according to this paper. But in everyday life, heavy might simply be moving from a three-pound dumbbell to a 10-pound dumbbell.
02:05:51
Speaker
It's about progression in a direction. It's not an absolute number. So we can hold a few truths at once, right? It doesn't have to be heavy, according to the evidence.
02:06:02
Speaker
Women deserve to know that. Heavy is relative. And women deserve to know that lifting more than the tiniest weights is both safe and beneficial and that the weights they progress toward will likely have to be heavier than the ones they started with.
02:06:18
Speaker
Heavy is a direction to move in. If you are lifting until the set becomes challenging at a certain point, adding more reps of a lightweight becomes less practical than just picking up a heavier weight.
02:06:28
Speaker
While all movement is good for health, not all movement does the same thing. For bone health, higher loads and higher impact, as well as moderate loads and moderate impact, offer benefits you simply won't get from lower intensity modes like or Pilates.
02:06:45
Speaker
Does the load have to be the exercise science version of heavy? Current evidence suggests it does not. But if we only ever say anything counts, I think we risk reinforcing the norms that have kept women away from heavier.

Benefits and Political Significance of Heavy Lifting

02:07:02
Speaker
Maybe it's the relative meaning as in heavier than what has been depicted, heavier from where you started, right? We risk keeping women from that type of training, that type of mindset. Like I should want these weights to get bigger in the first place.
02:07:19
Speaker
And that's why for our audience, many of whom are already active through yoga or Pilates, our message is different. We want to challenge the belief that heavy or heavier is dangerous.
02:07:31
Speaker
We want to flip the script and say women do lift weights. Women can lift heavy things. Heavy is not scary. Heavy is a direction to head in. Doesn't have to be a destination that you arrive at ever or even stay in.
02:07:46
Speaker
Maybe you visit it once and decide never again. But if you're even afraid to head in that direction, that's a problem. Yeah. What do you think are some benefits of lifting heavy, maybe from a more practical standpoint, that people won't realize until they they start?
02:08:03
Speaker
I mean, I know I didn't realize some of these benefits. Totally. With heavy lifting, it is easier to get to full recruitment, which is what they're talking about when they describe the effort in a lot of these trials, that it must be challenging.
02:08:20
Speaker
right? Heavy lifting is full recruitment from rep one because it has to be because it's heavy. Whereas for moderate, and usually like roughly the first half is pretty easy.
02:08:33
Speaker
The second half gets increasingly hard. And then it's those last few reps, you have that kind of burning sensation, right? So let's say you're doing a set of 10, first five, pretty straightforward. 6, 7, 8, getting harder.
02:08:45
Speaker
9, 10, you're like, whoa, I'm really starting to feel it, right? Yeah. For a lightweight, most of the set, and at this point we're talking about over 15 repetitions, right? Most of the set feels easy.
02:08:57
Speaker
And then the very last few reps feel hard, but you have more time with this kind of like burning sensation. I mean, it just, it's a time suck because you're out there having to do like 20 reps you know, biceps curls or something or whatever the exercise is, right? Because that's only when you get to that full recruitment point is by like number 18, number 19, number 20. Yeah. It can get a little boring.
02:09:23
Speaker
It just takes a long time. It doesn't feel as good. I don't like the way it feels in my body to do like massive sets of low load. Yeah. And that's a preference thing. But yeah yeah, I mean, I agree with you. These are just our opinions, folks. Yeah.
02:09:35
Speaker
of the concepts we use in weightlifting is something called RIR. stands for reps and reserve. So reps and reserve is talking about basically like how close you are to failure, right? With heavy, because you're doing that full recruitment from the first repetition, unless you're like in a competition, just regular day-to-day lifting, you want to keep more reps and reserve.
02:09:56
Speaker
right, you want to stay away from that total failure point, you're still going to get all the benefits of heavy lifting while not going as close to failure. For moderate and for light, you're going to have to go closer to failure. You're going to leave fewer repetitions in reserve. For moderate, you might leave one or two. For light, you might have to go to full failure in order to actually make it to that full recruitment challenging place. Can you tell us why that is, Sarah?
02:10:22
Speaker
Because of something called the size principle, right? And this is about how when you use your muscle, your nervous system doesn't just light them up all at once, all fibers of the muscle at once, or even all the muscles at once, right?
02:10:36
Speaker
So think of it like picking up a glass. If you're picking up an empty glass, you don't have to use your entire arm strength to pick that glass up. You look at it, you know it's light. Your brain says to your nervous system, hey, just recruit a few motor units to do this.
02:10:51
Speaker
Versus picking up one of those big water jug, change out the giant water jug, flip it over the top, spill it over yourself, that whole scenario. Yeah. You look at that and your nervous system goes, lady, you better recruit everything for this because that sucker is heavy, right?
02:11:06
Speaker
So your muscles will be energy efficient at first, but they're going to bring in the heavy power when the situation demands it. Yeah. Yeah. Those are you know discoveries we've made about why lifting heavy can sometimes actually be more straightforward, right? You don't have to go as close to failure.
02:11:26
Speaker
It's challenging from rep one. The fatigue experience is different. And in some cases, less uncomfortable, in my opinion. Yeah, yeah. You also don't do as many reps. So I like the distribution of time spent lifting to time spent resting. Like when I lift heavy, I get to rest more. Yeah.
02:11:47
Speaker
It's like mostly w resting. Right. It's mostly resting. yeah And then lifting heavy shit is better for improving your max force production. Yeah. Which big longitudinal studies don't show actually that it's important specifically to lift heavy for any type of longevity benefit.
02:12:04
Speaker
I think they've done quite a bit of studies on power lifters, for example. If you study power lifters and longevity, I don't actually know if this study exists. It probably does though. You might find that they they don't live as long, but that could also be because a lot of them are anti-cardio.
02:12:18
Speaker
And they're on like super high protein, high fat diets. You know, they're all anti-carb sometimes. A lot of them, their only exercise is bench, deadlift and squat and heavy ones. So, you know, yeah, that aside, right? So maybe there aren't papers showing that people specifically who lift heavyweights live longer.
02:12:39
Speaker
But you inevitably have to lift heavy shit in your life. And one of the best ways to get injured is to be unprepared for the forces your body has to experience. And sometimes we just don't have a choice.
02:12:50
Speaker
Okay. I've got to lift this thing. I've got to lift this child. I've got to lift this dog. Right. I've got to lift this grandparent off the floor. I've got to do these things that my life demands of me now that heavy lifting that you do will make you better capable of completing those tasks and it's protective, right? You will not be overwhelmed.
02:13:11
Speaker
You will be able to handle it because you can handle weights that are potentially two and three times heavier than that in training, right? Yeah, we think lifting heavy shit has lots of psychosocial benefits specifically for women.
02:13:24
Speaker
Yeah. But we also feel there are some practical benefits within training and also some functional benefits outside of training, making it an attractive thing to engage in, I think, for simply benefit, life benefit, right? yeah Yeah. Sarah, so is our course going to change? Do we have to like redo it?
02:13:47
Speaker
Well... Thankfully, no. Yeah. Because here's the thing. At its core, our course is for people to learn how to use barbells. Yeah.
02:13:58
Speaker
That's really it. Yep. Most of the women on our course have never used barbells before. We would be just sadistic, lunatic, chaos monsters.
02:14:13
Speaker
but We started month one of beginners lifting barbells with heavy lifting. It just makes nuts. Nobody ever talks about this when they're talking about heavy lifting. They talk about heavy lifting like that's where you start.
02:14:26
Speaker
It makes me nuts if you can't tell. Are you bothered? I can't tell. I'm bothered. Well, I'm like, why Why? what Why are we leaving this out? like o Anyway, so while, yes, this paper forced us to revise our message and we are fine with that, ironically, it actually supports our course more strongly than lift more by itself or lift heavy shit narrative ever did because our course has always included moderate intensity work.
02:14:59
Speaker
Yeah, like but most of it. and The majority, the majority of our course is moderate intensive work alongside heavy and impact training. Like we're in month four right now and we have just now started to enter the parameters of heavy lifting. Yeah.
02:15:12
Speaker
Yeah. And in one or two exercises in one or two exercises, a third of the exercises in a workout might move toward heavy. And then the other two thirds are moderate and some are light. Which is great because according to this review, the moderate intensity work that people are doing in our course, it also works.
02:15:27
Speaker
Yep. Potentially just as well as heavy. Yes. And maybe the light intensity as well. And like I said, this is great fucking news, right? Yeah, absolutely. All right. Well, we hope that you have enjoyed this fucking enormous episode that has been thing we've been working on literally since April.
02:15:46
Speaker
Yeah. In various ways. So thank you if you made it this far. I feel like we're going to have some drop off. Thank you for staying with us.
02:15:57
Speaker
Sarah, any closing thoughts? Yeah, I have some closing thoughts. I know you do.
02:16:03
Speaker
So outside of everything that we just talked about, I believe Laurel would agree with me about this. I'm always going to promote heavy lifting to women, in particular to women over 40 who have historically been excluded from this exercise domain.
02:16:21
Speaker
Knowing that the light and moderate lifting that you do when you are learning to lift weights on the way to heavy lifting will also have bone building benefits. Knowing that is just the icing on the cake.
02:16:35
Speaker
Great. Becoming someone who lifts heavy things is not just about the physiological benefits, in particular for women. It's about stepping into your own power as a woman.
02:16:47
Speaker
and refusing to behave according to patriarchal norms and roles. strongly believe that we can't talk about exercise for women without addressing the context.
02:17:01
Speaker
And you really only have to ask women who have learned to lift heavy how it's changed the rest of their lives in order to see this, right? My mom started deadlifting and within weeks she told me it made her less afraid to walk the dog at night.
02:17:17
Speaker
Women describe greater confidence in how they move through the world and a level of self-sufficiency that they have never had before. Yeah. And there's all kinds of posts on Instagram about how lifting heavy as a woman is a political act, including one that I made.
02:17:36
Speaker
Our message is and always will be that women belong strong.
02:17:42
Speaker
Nice. I think that's a perfect way to end the episode. course, we also have to say all the things like... Rate, review, subscribe. Yeah. Rate, review, subscribe. Oh, we got... Yeah.
02:17:54
Speaker
Everyone head to the head to the reviews right now and read the latest. We have a really spicy one.
02:18:02
Speaker
We're going to read it on air, but you might want to go there now. And while you're there, if you don't mind, just tap that five stars. we got a really spicy review. And please join us on the interest list.
02:18:15
Speaker
Yes. Get it some great course freebies you're going to see Sarah and I in our teacher element. You'll learn some things, some exercises, you'll learn some tools for strength training.
02:18:26
Speaker
And you'll also potentially get a big discount, the only discount on our course if you choose to join us. We hope you do. And you'll find out when we're starting so you won't miss a beat.
02:18:38
Speaker
All right, everybody. We are officially in season seven. See you next week. Yay.