Episode #362: Weighted Vests

0:00 [SPEAKER_00]: Welcome back to the Barbell Medicine podcast. [SPEAKER_00]: I'm Dr. Jordan Faganbaum. [SPEAKER_00]: I hope you had a great weekend. [SPEAKER_00]: In this podcast, I wanted to talk about one of the most recent trends in the fitness scene. [SPEAKER_00]: Weighted vests. [SPEAKER_00]: Influencers on social media have been promoting the use of weighted vests while walking and other forms of exercise in order to burn more calories, build muscle, and maintain strong bones.

0:20 [SPEAKER_00]: Heck, there's even a new equinox fitness program centered around using their three hundred and seventy five dollar weighted vests. [SPEAKER_00]: With all this interest in weighted vests, I thought it might be useful to do a deep dive into the topic to see if the hype is warranted. [SPEAKER_00]: In this episode, I'll review the factors that determine how many calories we use during exercise, along with what the scientific evidence says about using weight vests for weight management, [SPEAKER_00]: Muscle strength, muscle growth, bone density, and more.

0:44 [SPEAKER_00]: All that and more, on this episode of the Bartol Medicine podcast. [SPEAKER_00]: But before we get into that, I wanted to mention that we have tickets available for our two-day health and performance seminar where myself, Dr. Baraki, Leo Lutz, and Tom Campatelli will provide in-depth lifting instruction and education on a variety of topics ranging from cardiovascular health and sarcopenia to nutrition and programming.

1:04 [SPEAKER_00]: Now, the seminar is going to be in San Antonio, Texas, September, twenty-eighth and twenty-first. [SPEAKER_00]: We'll be training with the attendees on Friday evening before the seminar and having dinner with everyone on Saturday. [SPEAKER_00]: So, come hang out with the Barbell Medicine crew.

1:16 [SPEAKER_00]: We'd love to see you there. [SPEAKER_00]: Click the link in the description below to get your ticket today. [SPEAKER_00]: Okay, I think a good place to start here is with what is probably the main reason people are wearing weighted vests to burn more calories when they're exercising in order to aid in weight management.

1:32 [SPEAKER_00]: Now, these are actually two separate outcomes that are not really the same. [SPEAKER_00]: In other words, it is totally possible that using a weighted vest during exercise does indeed increase the amount of energy being used, which we measure in calories. [SPEAKER_00]: But also, at the same time, not help with weight management.

1:46 [SPEAKER_00]: Now to understand this a bit better, let's talk about energy expenditure during exercise in general and then focus on how wearing a weighted vest affects it. [SPEAKER_00]: The first off, let's start with total daily energy expenditure. [SPEAKER_00]: Now this is the total amount of energy used per day, which again is measured in calories.

2:03 [SPEAKER_00]: The three components of total daily energy expenditure, which is abbreviated TDE, are resting energy expenditure, diet-induced energy expenditure, and activity-induced energy expenditure. [SPEAKER_00]: Now, resting energy expenditure is the amount of energy used to sustain basic life processes such as breathing, heart function, and other essential tissue functions while an individual is awake, and it accounts for about sixty percent of total daily energy expenditure.

2:29 [SPEAKER_00]: This is just keeping the lights on in the body. [SPEAKER_00]: Now diet induced energy expenditure, which is also known as the thermic effect of food, describes the energy required to digest, absorb, transport, and store energy from food, and it represents about ten to fifteen percent of total daily energy expenditure.

2:46 [SPEAKER_00]: Lastly, activity induced energy expenditure refers to the calories used during exercise and non-exercise activity. [SPEAKER_00]: Exercise activity would be things that are purposeful, repetitive, and goal-directed towards improving health and fitness, whereas non-exercise activity includes occupational activity, chores, and involuntary activities such as fidgeting, twitches, frequent standing, and other subconscious movements.

3:09 [SPEAKER_00]: Sometimes those are called spontaneous physical activities or spa. [SPEAKER_00]: Now, activity induced energy expenditure is the most variable component of total energy expenditure, and it's typically between about twenty to forty percent of the total amount of calories you burn per day, or your TDEE.

3:26 [SPEAKER_00]: Again, we measure the energy expenditure or, quote, cost of an activity in calories. [SPEAKER_00]: And if you ever wanted to know how many calories that you need in a day, well, we have a free calculator on our website that can help you out. [SPEAKER_00]: It's linked in the show notes below.

3:40 [SPEAKER_00]: Now, the energy cost of exercise has a dose dependent relationship with activity specific factors such as intensity, duration, the amount of muscle mass used, and the economy of movement. [SPEAKER_00]: Increases in exercise intensity, increases in exercise duration, and the amount of muscle mass being used increased the amount of calories being used during exercise.

4:03 [SPEAKER_00]: In contrast, improvements in movement economy decrease the energy costs of movements as the individual adapts to the exercise that they're doing because they become more efficient. [SPEAKER_00]: And one study, and this is one of my favorites, the energy cost of individuals training for a half marathon did not increase when the weekly running distance was increased from twenty five to fifty kilometers per week.

4:26 [SPEAKER_00]: They doubled the distance that they were doing per week, but the amount of energy it cost them on a weekly basis to do all this running didn't go up. [SPEAKER_00]: Yeah, check that one out. [SPEAKER_00]: Now, environmental factors such as ambient conditions, training surfaces, et cetera can also influence an activity's energy cost by altering the metabolic requirements for force production by the muscles during a specific task.

4:49 [SPEAKER_00]: For example, running on a soft sandy beach into a headwind requires additional force production to maintain a given velocity compared to running on a track with calm winds. [SPEAKER_00]: It should be noted, however, that changes in temperature do not appear to have a significant effect on energy cost during exercise, though they do appear to influence eating behaviors after a workout.

5:11 [SPEAKER_00]: When it's colder outside, eating tends to be increased, so there's an increase in energy intake, and with warmer temperatures, those are associated with a decrease in post workout energy intake, whether or not this has an effect on body weight, long term, well, that still remains yet to be proven.

5:27 [SPEAKER_00]: Now, in addition to the energy used during a workout, exercise increases energy demands post workout in order to support recovery and other associated processes when an individual is at rest. [SPEAKER_00]: For example, increases in muscle protein synthesis rates in the post-workout period are thought to represent a significant increase in resting energy expenditure.

5:49 [SPEAKER_00]: The increase in energy demands necessitates additional oxygen consumption, which is known as excess post-exercise oxygen consumption, or the acronym EPOC. [SPEAKER_00]: The energy used during epoch increases with intensity, training volume, and the amount of muscle mass being used, and it decreases as individuals become more adapted to training.

6:10 [SPEAKER_00]: A number of studies have suggested that resistance training increases epoch to a higher level than aerobic training. [SPEAKER_00]: But this isn't the whole story. [SPEAKER_00]: It mostly seems to be true that epoch is higher after lifting weights in training naive individuals. [SPEAKER_00]: They're relatively untrained or new to lifting weights.

6:27 [SPEAKER_00]: However, when you compare trained individuals from aerobic training or even interval work compared to resistance training, it's not so clear that there's a big benefit or advantage of resistance training when it comes to the amount of energy used during epoch or for epoch. [SPEAKER_00]: It also appears that the overall effect of epoch on twenty four hour energy expenditure, also how many calories you burn in a day, will is relatively modest for most workouts and training schedules.

6:53 [SPEAKER_00]: This brings up at least two big important points regarding exercise and energy expenditure. [SPEAKER_00]: So point one, the amount of energy used by the body due to exercise is not purely additive to total daily energy expenditure. [SPEAKER_00]: In other words, if I personally have a baseline total daily energy expenditure of three thousand calories per day without exercise.

7:16 [SPEAKER_00]: And then the exercise that I complete costs another thousand calories. [SPEAKER_00]: My total daily energy expenditure is unlikely to be four thousand calories. [SPEAKER_00]: You can't just add the two numbers together. [SPEAKER_00]: Instead, it'll be something a little bit less than that due to the body compensating and subsequently using less energy for other components of metabolism.

7:38 [SPEAKER_00]: How much less varies amongst individuals due to their genetics, their weight-change history, particularly recent weight-change history, their current nutritional status, the type of exercise they're doing, the amount of exercise they're doing, and more. [SPEAKER_00]: Now, this constrained energy expenditure model, as it's known, is still an active area of research also controversy, though the majority of individuals who exercise will experience it on some level.

8:02 [SPEAKER_00]: The crux of this first point is simply this. [SPEAKER_00]: Whether someone is in a research setting or the real world, weight loss from exercise is usually less than what would be predicted purely from the calorie deficit calculated by adding someone's exercise on top of their total daily energy expenditure.

8:18 [SPEAKER_00]: Now for more on the constrained energy expenditure model, check out the podcast with Dr. Herman Ponser, author of the book, burn and adaptable. [SPEAKER_00]: and it's linked in the show notes below. [SPEAKER_00]: Now, the second point here, and one that I think is more important than arguing over additive versus constrained energy models of exercise.

8:36 [SPEAKER_00]: Well, it's that the benefits of exercise are far more worthwhile than anything having to do with weight loss and calories. [SPEAKER_00]: Exercise benefits virtually every organ system in the body. [SPEAKER_00]: From your brain to your bones and your muscles to your metabolic function, exercise improves the form and function of virtually everything.

8:53 [SPEAKER_00]: Regardless of whether someone loses weight or not, using exercise to burn calories, misses the forest for the trees. [SPEAKER_00]: Yes, exercise costs energy, but most of its benefits on health and fitness are independent of changes in body weight. [SPEAKER_00]: Now with all that in mind, does wearing a weighted vest increase the amount of calories used during exercise?

9:14 [SPEAKER_00]: By wearing a weighted vest during exercise, we would predict that an individual would burn more calories with the same amount of exercise activity, like the duration or the volume, and if it's done at the same intensity. [SPEAKER_00]: The muscles have to create more force to deal with the added weight, and that costs more calories.

9:30 [SPEAKER_00]: That's pretty straightforward. [SPEAKER_00]: However, one might predict that exercising with the weighted vest is harder, perhaps reducing the time that one exercises for, or making them otherwise reduce the intensity of their exercise by going slower. [SPEAKER_00]: Thereby, reducing the total calorie cost of exercise.

9:47 [SPEAKER_00]: Let's take a look here at some science. [SPEAKER_00]: One study on nine young healthy women had them do a graded exercise test on a treadmill, unloaded, or carrying a seventy pound rucksack, or wearing a seventy pound weighted vest until exhaustion. [SPEAKER_00]: In the unloaded test, they exercise for about twenty minutes before exhaustion, whereas they quit after only eleven minutes with the weighted vest and six and a half minutes with the rucksack.

10:11 [SPEAKER_00]: It does seem like wearing one of these weighted vest or adding weight to the activity does tend to decrease the amount of time [SPEAKER_00]: that people will exercise for. [SPEAKER_00]: Now, in another study, twenty healthy adults walked on a treadmill unloaded or carrying twenty-two percent, forty-four percent, or sixty-six percent of their body mass in a weighted vest.

10:30 [SPEAKER_00]: The treadmill tests included an increase in speed every two minutes until the person could no longer maintain the pace without jogging or running. [SPEAKER_00]: Energy expenditure was measured during these tests. [SPEAKER_00]: The results [SPEAKER_00]: While energy cost went up with increased loads being carried, the total amount of calories burned was not that different between each condition, as it is affected by other variables like speed, terrain and grade.

10:54 [SPEAKER_00]: For example, a seventy-five kilo adult walking at three miles an hour on level pavement is predicted to burn two hundred eighty-two calories per hour. [SPEAKER_00]: If we add a vest that weighs five percent of their body weight, well, yeah, the number goes up, but only to two hundred ninety calories per hour.

11:11 [SPEAKER_00]: And if we increase the weight of the vest even more to ten percent of the individual's body weight with the same speed, the same terrain, et cetera, well, that would cost three hundred calories per hour. [SPEAKER_00]: To put this into perspective, if you're a hundred sixty-five pounds and you walk for an hour with the sixteen pound vest, you are likely to only burn on extra eighteen calories in that hour compared to walking without a vest.

11:34 [SPEAKER_00]: And that's assuming you are walking at the same speed and for the same duration you don't call it in early. [SPEAKER_00]: You speed and or time spent exercising goes down. [SPEAKER_00]: It's probably a wash. [SPEAKER_00]: To summarize, wearing a weighted vest does seem to increase the amount of energy or calories used compared to being unloaded.

11:51 [SPEAKER_00]: Provided the exercise is performed at the same pace and for the same duration or volume. [SPEAKER_00]: However, the amount of additional calories being burned is modest, and the additional weight from the vest does tend to make the exercise more difficult to complete at the same pace and duration, perhaps limiting its utility for this purpose.

12:08 [SPEAKER_00]: Okay, so now on to the next question, does this potential increase in calorie cost during exercise from wearing a weighted vest? [SPEAKER_00]: Does it lead to greater weight loss or greater ability to manage someone's weight? [SPEAKER_00]: Let's take a look at some research. [SPEAKER_00]: One study looked at eighteen older adults with osteoarthritis who were losing weight.

12:27 [SPEAKER_00]: During the six-month trial, all subjects consumed a shake-based diet of around twelve hundred calories per day in order to lose weight. [SPEAKER_00]: Half of the subjects were randomly assigned to wear a weight vest up to ten hours per day, with the weight of the vest gradually increasing up to fifteen percent of the individual's starting weight.

12:44 [SPEAKER_00]: Over the six months study, both groups lost about the same amount of weight, right at about eleven kilograms. [SPEAKER_00]: Despite the vest wearers carrying around extra weight for an average of six point six hours per day, both groups also lost about the same amount of lean body mass, about three kilos.

13:00 [SPEAKER_00]: In the subsequent eighteen months, however, [SPEAKER_00]: There was much less weight regain in the group who wore the weighted vests. [SPEAKER_00]: However, it's not clear that they were actually wearing the vests after the initial six month study period, so we don't know if this is due to continued use of the weight vests or if maybe wearing the weight vests during the weight loss period did something unique.

13:19 [SPEAKER_00]: Hmm, that's interesting. [SPEAKER_00]: Maybe there's something to the effect of loading the body for extended periods of time and subsequent weight management. [SPEAKER_00]: This has actually been discussed before, even on this podcast, and we call this the Gravitostat theory. [SPEAKER_00]: Now, researchers from Sweden hypothesize that the body uses gravity as a regulator of body weight and body fat.

13:40 [SPEAKER_00]: So, called Gravitostat theory, it's this idea that there are specific cells in the bones and elsewhere that sense the amount of weight being carried around. [SPEAKER_00]: One of the first studies on this was actually done in rodents, so in this study, they implanted capsules weighing fifteen percent of the rodents body weight into their abdoments, whereas the control rodents had an empty capsule of equal size implanted.

14:05 [SPEAKER_00]: After two weeks, about eighty percent of the added capsule weight was lost in the rodents with the heavy capsule implanted, and these rodents weighed about the same as the controls, despite still having the heavy capsule implanted. [SPEAKER_00]: Now, that was like two thousand eighteen, [SPEAKER_00]: So subsequently, has there been any research in humans?

14:22 [SPEAKER_00]: Yes, there has. [SPEAKER_00]: One study had ten adult humans, where a weighted vest weighing about thirteen and a half percent of their body weight for a week, followed by not wearing the vest for the following week. [SPEAKER_00]: They wore the vest for just over eight hours each day, mean hourly ratings for hunger and snack cravings as well as daily peak hunger were marginally lower in those wearing the vest.

14:46 [SPEAKER_00]: But the researchers didn't measure changes in weight or energy intake to see if these differences really meant anything. [SPEAKER_00]: So did they actually eat less because they rated their hunger as lower? [SPEAKER_00]: Did they lose more weight because of these changes in appetite and feelings of fullness or satiety?

15:01 [SPEAKER_00]: We'll never know. [SPEAKER_00]: Another study compared thirty-six adults with obesity, who were wearing a weight vest that weighed about eleven percent of their body weight for eight hours per day, with thirty-three adults wearing a weight vest that weighed about one percent of their body weight over three weeks.

15:18 [SPEAKER_00]: Those wearing the heavier weight vest lost three and a half pounds during the study period, while the light vest group only lost a half a pound. [SPEAKER_00]: The heavy vest wearing group also lost four percent more fat mass, though fat remas was unchanged between groups. [SPEAKER_00]: A longer term human study showed no weight or fat loss benefits to wearing a vest.

15:38 [SPEAKER_00]: that was ten percent of the individuals bodyweight for nearly seven hours a day over five months as compared to not wearing a vest at all. [SPEAKER_00]: In one of the largest single studies done on wearing weight vest, they took a hundred and fifty older adults with obesity who were enrolled into a study that was designed to help them lose ten percent of their bodyweight through dietary changes.

15:57 [SPEAKER_00]: Now the subjects were randomized into one of three groups, where group one just did the diet only, diet only intervention, group two did the diet and they wore a weighted vest, and group three did the diet, they wore the weighted vest, and they lifted weights three times per week, at the end of a year.

16:14 [SPEAKER_00]: twelve months of follow-up. [SPEAKER_00]: The amount of weight loss was about the same in all groups at about nine kilograms, despite the weighted vest groups wearing the vest for an average of seven hours per day. [SPEAKER_00]: There were no differences in resulting bone mineral density measurements, either.

16:29 [SPEAKER_00]: In fact, the biggest differences between the groups were loss of body fat and changes in muscle strength. [SPEAKER_00]: Unsurprisingly, the group lifting weights three times per week lost more fat mass and gained more muscle strength than the other groups. [SPEAKER_00]: Now, for those of you keeping score at home, there were no differences between the diet only group and the diet and weight vest group for amount of body fat, loss, or muscle strength, so it didn't really seem like the weighted vest had much of an effect on that.

16:55 [SPEAKER_00]: So overall, it does not appear that wearing a weighted vest improves weight loss or body composition as compared to doing the same amount of exercise at the same intensity, but not wearing a vest. [SPEAKER_00]: Whether or not wearing a weighted vest reduces the propensity of an individual to regain weight after weight loss is mostly speculative and would need to be tested further to feel confident about this finding.

17:17 [SPEAKER_00]: Weight vests also do not appear to increase bone mineral density in vulnerable populations. [SPEAKER_00]: You'd expect older folks with osteoarthritis who previously hadn't been loaded that much to respond relatively well if there was an effect here, but they didn't. [SPEAKER_00]: We'll still need more evidence here to comment confidently one way or the other, however.

17:36 [SPEAKER_00]: Between the very small potential increase in calorie expenditure and the non-existent benefit on weight or fat loss from wearing a weighted vest during exercise, I think it's pretty safe to say this theory has been debunked for the moment. [SPEAKER_00]: Now, if new data comes out, I'm open to changing my mind, but that's where I'm out for now.

17:52 [SPEAKER_00]: But that doesn't mean that weighted vest are all bad. [SPEAKER_00]: When we come back from this break, I'll cover the best use cases for a weight vest based on the current science, increasing intensity. [SPEAKER_00]: All right, we're back here on the Barbell Medicine podcast. [SPEAKER_00]: We're talking about weighted vests.

18:07 [SPEAKER_00]: And how to use them? [SPEAKER_00]: Is there some good evidence behind using a weighted vest? [SPEAKER_00]: And in my opinion, the answer is yes, when it comes to increasing exercise intensity, should you need to do that? [SPEAKER_00]: So let's start with conditioning. [SPEAKER_00]: In conditioning, intensity refers to the metabolic demand of the activity.

18:25 [SPEAKER_00]: There are many ways to express exercise intensity. [SPEAKER_00]: You can use oxygen consumption, power output, heart rate, speed, and more, but whether it's expressed in absolute or relative terms, intensity determines the nature of the physiological stress that an individual experiences during exercise, which influences the type of fitness and health adaptations obtained from exercise.

18:47 [SPEAKER_00]: Now, in a recent meta-analysis on weighted vests used during conditioning or cardio, the average increase in heart rate while walking at a self-selected pace is about seven percent. [SPEAKER_00]: And yeah, you get an increase in blood lactate level. [SPEAKER_00]: Together, these demonstrate that using a weighted vest while you're walking or doing a similar type of conditioning exercise should increase the heart rate compared to not using a weighted vest.

19:11 [SPEAKER_00]: Now because of the increase in heart rate and other associated physiological variables, a weight vest can be useful for folks who prefer walking as their main type of conditioning exercise, but who are able to walk at a high enough speed to get to the appropriate exercise intensity and subsequently generate the desired adaptations.

19:28 [SPEAKER_00]: For example, if a person cannot walk fast enough to get to sixty to seventy percent of their max heart rate, all of the future race walkers you guys can just stop listening right now because you are well above that. [SPEAKER_00]: Those folks though, adding a weight vest may help them get to this higher intensity level thereby generating the desired fitness adaptations.

19:47 [SPEAKER_00]: Again, that assumes the person's going to walk for as long. [SPEAKER_00]: but the duration is not going to suffer and also they're not actually walking slower because they're wearing the thing that's heavier. [SPEAKER_00]: In contrast, if a person who can otherwise exercise at the appropriate intensity without a vest and then adds a weight vest, they may increase their exercise intensity too high.

20:07 [SPEAKER_00]: They're violating to unnecessary fatigue and less of the fitness adaptations they're looking for. [SPEAKER_00]: is a person who would otherwise be able to walk and get their heart rate up to sixty percent, seventy percent of their max heart rate. [SPEAKER_00]: They put a weight vest on and they really try to push it and now they're eighty five or ninety percent of their max heart rate.

20:23 [SPEAKER_00]: Those are two distinctly different sets of fitness adaptations. [SPEAKER_00]: Though of course there's some overlap and one just costs a lot more with respect to fatigue. [SPEAKER_00]: That's why we don't program high intensity interval training all the time or sprint intensity training all the time.

20:37 [SPEAKER_00]: Those are merely accoutrements to the main course of people's conditioning which should be moderate intensity continuous training for the most part. [SPEAKER_00]: Now in resistance training intensity refers to the weight used for an exercise in either absolute or relative terms. [SPEAKER_00]: It's typically defined in the literature as a percent of a one repetition maximum, which is also known as a one Rm, so like seventy five percent of a one Rm for five reps, seventy five percent tells you the weight, five reps tells you the volume, and yeah, you're off to the races.

21:09 [SPEAKER_00]: So using a weighted vest can be helpful for adding external load to the individual if they're training at home, if the traveling or when equipment is otherwise limited, like a recent pandemic, for example. [SPEAKER_00]: Now, in most situations, exercise selection for resistance training for lifting weights should focus on finding movements that get the individual somewhere close to muscular failure with the equipment available without compromising range of motion, without compromising tempo with these other factors.

21:40 [SPEAKER_00]: Now, practically speaking, this means getting to within about five repetitions of muscular failure, really known as task failure, specific to the exercise. [SPEAKER_00]: For most dynamic exercises or about twenty to thirty seconds within failure for isometric exercises. [SPEAKER_00]: Again, muscular failure here or task failure means the point at which you could no longer perform another repetition or or or are unable to hold an isometric position any longer.

22:08 [SPEAKER_00]: weighted best, maybe helpful for getting to this point. [SPEAKER_00]: So for example, imagine that an individual is trying to pick a lower body exercise that gets them to about RPE eight, which means that they have two repetitions left in reserve somewhere in that eight to twelve repetition range.

22:26 [SPEAKER_00]: They may see on the workout plan, hey, do a lower body exercise like a squat or similar for a set of eight to twelve at RPE eight or multiple sets of eight to twelve reps at RPE eight. [SPEAKER_00]: Bodyweight only squats with a full range of motion are way too easy for this person. [SPEAKER_00]: As doing twelve repetitions isn't even an RP-five for that mean they could do at least five more repetitions.

22:48 [SPEAKER_00]: In this case, we'd recommend trying to add load so you could use a weighted vest or a loaded backpack, dumbbell, barbell, kettlebell. [SPEAKER_00]: I think there are other bills available that have ballast to them. [SPEAKER_00]: Ultimately, though, they all work the same. [SPEAKER_00]: They're making the muscles work against a heavier load to try to ultimately hit the appropriate RPE prescription for the given rep range.

23:11 [SPEAKER_00]: Now, there's some evidence that wearing a weighted vest is a viable alternative to other more traditional ways to add loads, such as a barbell, dumbbell, kettlebell, or band, or whatever else the internet produces in the next few years. [SPEAKER_00]: So when we add weight to a given movement, we expect to see higher measurements of muscular activity.

23:30 [SPEAKER_00]: We can consider the pushup as a good example here. [SPEAKER_00]: So, previous research has shown that a regular push-ups, so from the feet or from the toes, requires an individual to lift about sixty-four percent of their body weight. [SPEAKER_00]: Whereas a kneeling push-up is closer to about forty-nine percent of their body weight.

23:48 [SPEAKER_00]: Now, compared to doing kneeling push-ups with body weight only, [SPEAKER_00]: wearing a weighted vest while doing them does increase muscle activity in some of the active muscles because they have to go against a heavier load for the same range of motion, otherwise would be completing without the weight vest.

24:03 [SPEAKER_00]: So a weighted vest could be a useful tool for loading various exercises where traditional weights would be cumbersome or more challenging. [SPEAKER_00]: Now another relationship we see amongst different resistance training programs is that heavier weights tend to work better than lighter ones for improving strength.

24:19 [SPEAKER_00]: Of course heavier doesn't mean maximal or training to failure per se. [SPEAKER_00]: As most of the research in the space draws the cutoff or high intensity at about sixty percent of an individual's one rep max. [SPEAKER_00]: In our traditional strength training type programs, so all of our strength templates, et cetera, we draw that cutoff closer to like sixty five to seventy percent of one rm meaning that if you're at that threshold or above, you're probably developing a good amount of strength.

24:45 [SPEAKER_00]: And if you're at below that level, we're not as confident. [SPEAKER_00]: So if using a weight vest during resistance training increases the load to get an individual closer to that cutoff, we'd predict greater strength gains. [SPEAKER_00]: In a recent study, thirty six women with obesity did circuit training with or without a weight vest.

25:03 [SPEAKER_00]: They did three times per week for eight weeks and while the weight and body fat loss across both groups was the same as was the improvement in VO two max. [SPEAKER_00]: The group who used the weighted vest saw a much larger improvement in their maximum strength. [SPEAKER_00]: which was measured by squatting when compared to just the body weight only group.

25:20 [SPEAKER_00]: So when it comes to exercise intensity, not weight loss or burning calories, adding weight can be useful in order to drive the desired adaptations. [SPEAKER_00]: Depending on the application, [SPEAKER_00]: A weight vest may be the best choice from an ergonomics perspective. [SPEAKER_00]: Provided the individual doesn't need to add too much weight.

25:36 [SPEAKER_00]: Most weight vest are limited to twenty to forty pounds. [SPEAKER_00]: And for conditioning purposes, if it makes the person walk much slower or move much slower or move for less, it's probably a wash. [SPEAKER_00]: Okay, that's it for this episode of the Barbell Medicine podcast. [SPEAKER_00]: If you like this episode, share it with a friend and leave us a five star review.

25:53 [SPEAKER_00]: Thanks so much for listening.