Does BODYPUMP Work? The Science Behind the Workout

The popular low-weight, high-rep BODYPUMP resistance workout claims to have science in its corner. Do those claims hold up to independent research?

After doing some undercover investigation into the Orangetheory Fitness gym chain, I received a flurry of email requests from listeners to look into other new gym fads like Pure Barre, Soul Cycle and BODYPUMP. So today, thanks to listeners Susan and Alyssa, I once again don my fake nose and mustache to get to the bottom of BODYPUMP.
The owner and creator of BODYPUMP (and yes, it is supposed to be in all-caps) is Les Mills who provides group fitness and team training programs for gyms all over the world. Les Mills offers strength, plyo, cardio, weights, martial arts, indoor cycling, and 30-minute high-intensity interval training all set to a custom playlist of music. They also sell clothing, workout equipment, music, and snacks. The company was founded in 1968 and is based in Auckland, New Zealand.

What is the BODYPUMP workout?
In a nutshell, BODYPUMP is a 30-, 45-, or 55-minute resistance workout that uses a barbell with very light weights and very high reps. Their theory behind the combo of lightweight and high reps is to “exhaust your muscles so you don’t get bulky, you just get strength and tone.” That makes very little sense if you break it down. Bodybuilders exhaust their muscles and so do marathon runners, but you couldn’t find two more diverse body types if you tried.

During the workout, you go through five or six specific exercises, in different combinations, and end up completing approximately 800 to 1000 reps in one 55-minute session. The BODYPUMP website says “The secret to BODYPUMP is The Rep Effect—a breakthrough in resistance training that helps create long, lean muscles and a toned, strong physique.” I'll get into the science behind this so-called Rep Effect later.
The exercises you can expect at a BODYPUMP workout are:

Chest Press
Squat
Deadrow
Clean and Press
Lunge
Reverse Curl
To complete the minimum of 800 reps, each exercise will have to be done 133 times during the workout. As they say in New Zealand, "That's a lot of reps, mate!" Having watched pretty much all the videos on the BODYPUMP website, it looks to me like there's a lot (and I do mean a lot) of Clean and Press going on.
Obviously, people who are new to BODYPUMP won’t start at 800 reps, they will work up to this. Or at least, they should. (Too much, too soon, anyone?)
Music is a big part of the BODYPUMP workout and each exercise is done to the rhythm of a particular song. The program has specific music tracks for all levels and the tempo increases as the class continues. For that reason, beginners are encouraged to only do the first few songs while veteran pumpers will do them all.
Music is a big part of the BODYPUMP workout and each exercise is done to the rhythm of a particular song.
An enterprising thing about BODYPUMP is that it's taught in most locations around the world as a group class but you can also buy the music tracks and SmartBar (their branded barbell) and do the program at home. Doing the workout two or three times a week, mixed in with one of the other Les Mills cardio workouts, is what they recommend, whether you are doing it as a class or at home.
The BODYPUMP website says “This full-body barbell workout will burn calories, shape, and tone your entire body, increase core strength and improve bone health.” I agree that many of the exercises involved in BODYPUMP are multi-joint and use many muscle groups. As you can read about in the article 10 Tips to Build Muscle Fast, this is one of the best ways to get fit. Single joint movements like biceps curls or triceps extensions do not build muscle quickly. Multi-joint exercises like cleans, deadlifts, and squats not only work more muscles in less time, but they also allow you to use a much heavier weight than you can lift with single-joint exercises. But that isn’t important here since the whole idea is to use a light weight.

The science (or lack of) behind the rep effect
The BODYPUMP website also says “This program is based on THE REP EFFECT, a proven formula that exhausts muscles using light weights, while performing high repetitions - this is the secret to developing lean, athletic muscle.” However, that exhausted and burning feeling you get from doing all those reps is likely just lactic acid building up faster than it can be flushed from your muscles. And although that is a marker of working hard, it doesn’t necessarily mean that the muscle is getting lean or more athletic.
As far as their claim of not bulking up and only developing these “lean athletic muscles,” (I’d like to know which muscles they consider to be non-athletic) that doesn’t make much sense either. In a rather famous study from 2015, the last nail was put in the coffin as to whether high reps with low weight or low reps with high weight developed more muscle mass. And it was a draw!
In the study, 18 young men, who were experienced in Resistance Training, were matched according to their baseline strength and then randomly assigned to one of two groups:

A low-weight routine where 25-35 repetitions were performed per set per exercise
A high-weight routine where 8-12 repetitions were performed per set per exercise
The findings indicated that both ways of training—"to failure," which is when you can’t manage to lift the weight one more time—can elicit significant increases in muscle hypertrophy (muscle building). The only difference was that the high weight training turned out to be better for maximizing strength gains.
So, if you want to create muscle, you can do it either way. But if you want to get strong, you need heavy weights with low reps.
Huh. So the BODYPUMP definition of the rep effect is a little questionable, but at least we know you will put on some muscle doing this workout. That's assuming you don’t choose such a light weight that you don’t get to failure even by the end of the 800 reps.

The risk of too many reps
The makers and promoters of BODYPUMP insist that muscular endurance is built by doing many repetitions of each exercise. But research shows that simply doing eight to 12 reps also develops muscular endurance, strength, bone, and muscle mass. So, not only is performing hundreds of repetitions unnecessary, it can be a quick way to a repetitive strain or overuse injury.
The researchers in a study of BODYPUMP participants worried that doing so many repetitions could result in some improper technique.
Not to mention the lack of functional movement involved in a repetitive workout like this. How often during a normal day do you lift something very light over your head 133 times in a row? On the other hand, how often do you need to lift something heavy out of a high cupboard and then put it back later?
The researchers in a study that was done specifically on BODYPUMP participants (which I will cover next) were also worried that doing that many repetitions could result in some improper technique (especially near the end of the class). One of the researchers said that she often saw poor form, especially among newcomers, and that the instructors rarely took the time to correct the individuals who were losing focus. I did notice at my local BODYPUMP gym that the instructors offer a 15-minute workshop that newcomers are strongly encouraged to attend at least once.

The BODYPUMP study
As a fitness writer, I rarely have the opportunity to present a study that fits exactly what I am writing about, but this is one of those rare occasions where someone went out and did my work for me.
In this study, 19 untrained but healthy women participated in two BODYPUMP training sessions per week for 12 weeks. The subjects had little to no experience with weight training and no training program at all for the six months leading up to the study.
Researchers took these measurements at the beginning and end of the study:

Maximal isotonic strength (4-repetition maximal squat)
Incremental test to exhaustion on a treadmill (for blood lactate threshold and maximal aerobic speed)
5-second maximal isometric voluntary contractions for knee extension and trunk extension\
Blood sample
Heart rate measurement
Electromyographic recording (which measures the electrical activity produced by skeletal muscles)
Anthropometric assessment (height, body mass, body fat measured by skinfold)
All 19 women took the same BODYPUMP class taught by the same instructor. The weight of the SmartBar given to the women at the beginning of the study was 10% of their 1RM squat weight. After two weeks, the weight on the bar was increased by 5%. It was increased again by 5% every two weeks.
After the 12 weeks, the results looked like this:

No changes in body weight or body fat
No changes in blood lactate threshold
No changes in maximal aerobic speed
33% improvement in squat strength
Increased isotonic strength
Lowered heart rate
So, what I take away from this is that the women got 33% better at doing squats (which was attributed to neural adaptations, not changes in muscle mass), they saw some improvement in fitness markers (which you would see in any sedentary participants that take up an exercise regimen), and not much else. Not exactly stunning results.

What I like about BODYPUMP
Group training is fun and sweating to music can give you a boost beyond the training itself.
Because you choose your own weight, this class can be for everyone regardless of age, gender, or experience. Although, certain injuries, mobility limitations, or other conditions could prevent you from participating in parts of the workout.
Although their website promises that you will “burn up to 560 calories during a 55-minute BODYPUMP workout” (which is dubious at best) they immediately change the focus of their marketing to “sculpting the body” rather than “losing weight.” As someone who spends much of his life preaching the wonderful health benefits of movement outside of weight loss, this makes me breathe a sigh of relief. You create a strong and capable body by moving it. It would appear that Les and I share this belief.
Much like Orangetheory Fitness the same workout is done around the world. If you like consistency and you happen to travel a lot, or you have a training partner on the other side of the globe, this could come in handy.

Is BODYPUMP good for beginners?
Is BODYPUMP a good workout for beginners? Sure. Taking any class like this is definitely a good way to get introduced to a variety of resistance training exercises, especially if you opt to take the 15-minute introductory technique class. And I definitely suggest you do that!
The BODYPUMP session moves quickly. If you don’t take the time to learn the movements in a controlled fashion ahead of time, you could easily find yourself floundering, frustrated, and at risk for injury.

What I don’t like about BODYPUMP
Like I said earlier, whether you are doing low reps with heavy weights or high reps with light weights, in order to put on muscle and get that “toned” look, you must lift to failure. I don't know about you but I would find it hard to estimate how heavy my SmartBar needs to be to lift to failure in a class that is 800 reps long.
Unless you have the focus and attention span of a ninja, doing 133 repetitions of anything is going to lead to sloppy form, and sloppy form leads to injury.
Unless you have the focus and attention span of a ninja, doing 133 reps of anything is going to lead to sloppy form and that leads to injury.
Although the movements and exercises are mainly multi-joint they are not very practical, functional, or useful in real life. Unless you are planning to pick up the same can of beans 133 times in a row.
I immediately get my back up when the word bulky is thrown around as being something to be avoided. First of all, bulking-up is not something that happens by accident because you chose the wrong class at the gym. Second, becoming “toned” is really just a combination of adding some mass (or bulk) to your muscles and losing some body fat to increase the definition of those muscles. I know it is just semantics but it bothers my inner coach.

How often should you do BODYPUMP?
As I mentioned earlier, the makers of BODYPUMP suggest doing the workout two or three times a week—mixed in with one of the other Les Mills cardio workouts—whether you're doing it as a class or at home. But as you can probably guess by now, I wouldn’t suggest spending that amount of your precious workout time with this workout.
If you really enjoy it, and doing a BODYPUMP class is really the thing that gets you out of bed in the morning, then it's fine to do a class once every seven to ten days.

If you really enjoy it, and doing a BODYPUMP class is really the thing that gets you out of bed in the morning, then it's fine to do a class once every seven to ten days. More than that, and it could start to cause overuse issues. And, as the study showed, even the participants who were doing BODYPUMP twice per week for 12 full weeks barely saw any meaningful results.
I am all in favor of anything that gets people moving more, and BODYPUMP sounds like a fun way to do that. Mixed in with other classes, activities, and a generally active lifestyle, I don't see a problem with attending the occasional BODYPUMP class.

The verdict
If I had a rating scale for the risk of injury from “too much, too soon” with a dash of “too repetitive,” BODYPUMP might just bump CrossFit out of the top position. Eight-hundred reps are just too many.

The popular low-weight, high-rep BODYPUMP resistance workout claims to have science in its corner. Do those claims hold up to independent research?

After doing some undercover investigation into the Orangetheory Fitness gym chain, I received a flurry of email requests from listeners to look into other new gym fads like Pure Barre, Soul Cycle and BODYPUMP. So today, thanks to listeners Susan and Alyssa, I once again don my fake nose and mustache to get to the bottom of BODYPUMP.
The owner and creator of BODYPUMP (and yes, it is supposed to be in all-caps) is Les Mills who provides group fitness and team training programs for gyms all over the world. Les Mills offers strength, plyo, cardio, weights, martial arts, indoor cycling, and 30-minute high-intensity interval training all set to a custom playlist of music. They also sell clothing, workout equipment, music, and snacks. The company was founded in 1968 and is based in Auckland, New Zealand.
(READ MORE): https://pumpers.co/for-sale-online/clomiphene-citrate/

What is the BODYPUMP workout?
In a nutshell, BODYPUMP is a 30-, 45-, or 55-minute resistance workout that uses a barbell with very light weights and very high reps. Their theory behind the combo of lightweight and high reps is to “exhaust your muscles so you don’t get bulky, you just get strength and tone.” That makes very little sense if you break it down. Bodybuilders exhaust their muscles and so do marathon runners, but you couldn’t find two more diverse body types if you tried.

During the workout, you go through five or six specific exercises, in different combinations, and end up completing approximately 800 to 1000 reps in one 55-minute session. The BODYPUMP website says “The secret to BODYPUMP is The Rep Effect—a breakthrough in resistance training that helps create long, lean muscles and a toned, strong physique.” I'll get into the science behind this so-called Rep Effect later.
The exercises you can expect at a BODYPUMP workout are:

Chest Press
Squat
Deadrow
Clean and Press
Lunge
Reverse Curl
To complete the minimum of 800 reps, each exercise will have to be done 133 times during the workout. As they say in New Zealand, "That's a lot of reps, mate!" Having watched pretty much all the videos on the BODYPUMP website, it looks to me like there's a lot (and I do mean a lot) of Clean and Press going on.
Obviously, people who are new to BODYPUMP won’t start at 800 reps, they will work up to this. Or at least, they should. (Too much, too soon, anyone?)
Music is a big part of the BODYPUMP workout and each exercise is done to the rhythm of a particular song. The program has specific music tracks for all levels and the tempo increases as the class continues. For that reason, beginners are encouraged to only do the first few songs while veteran pumpers will do them all.
Music is a big part of the BODYPUMP workout and each exercise is done to the rhythm of a particular song.
An enterprising thing about BODYPUMP is that it's taught in most locations around the world as a group class but you can also buy the music tracks and SmartBar (their branded barbell) and do the program at home. Doing the workout two or three times a week, mixed in with one of the other Les Mills cardio workouts, is what they recommend, whether you are doing it as a class or at home.
The BODYPUMP website says “This full-body barbell workout will burn calories, shape, and tone your entire body, increase core strength and improve bone health.” I agree that many of the exercises involved in BODYPUMP are multi-joint and use many muscle groups. As you can read about in the article 10 Tips to Build Muscle Fast, this is one of the best ways to get fit. Single joint movements like biceps curls or triceps extensions do not build muscle quickly. Multi-joint exercises like cleans, deadlifts, and squats not only work more muscles in less time, but they also allow you to use a much heavier weight than you can lift with single-joint exercises. But that isn’t important here since the whole idea is to use a light weight.

The science (or lack of) behind the rep effect
The BODYPUMP website also says “This program is based on THE REP EFFECT, a proven formula that exhausts muscles using light weights, while performing high repetitions - this is the secret to developing lean, athletic muscle.” However, that exhausted and burning feeling you get from doing all those reps is likely just lactic acid building up faster than it can be flushed from your muscles. And although that is a marker of working hard, it doesn’t necessarily mean that the muscle is getting lean or more athletic.
As far as their claim of not bulking up and only developing these “lean athletic muscles,” (I’d like to know which muscles they consider to be non-athletic) that doesn’t make much sense either. In a rather famous study from 2015, the last nail was put in the coffin as to whether high reps with low weight or low reps with high weight developed more muscle mass. And it was a draw!
In the study, 18 young men, who were experienced in Resistance Training, were matched according to their baseline strength and then randomly assigned to one of two groups:

A low-weight routine where 25-35 repetitions were performed per set per exercise
A high-weight routine where 8-12 repetitions were performed per set per exercise
The findings indicated that both ways of training—"to failure," which is when you can’t manage to lift the weight one more time—can elicit significant increases in muscle hypertrophy (muscle building). The only difference was that the high weight training turned out to be better for maximizing strength gains.
So, if you want to create muscle, you can do it either way. But if you want to get strong, you need heavy weights with low reps.
Huh. So the BODYPUMP definition of the rep effect is a little questionable, but at least we know you will put on some muscle doing this workout. That's assuming you don’t choose such a light weight that you don’t get to failure even by the end of the 800 reps.

The risk of too many reps
The makers and promoters of BODYPUMP insist that muscular endurance is built by doing many repetitions of each exercise. But research shows that simply doing eight to 12 reps also develops muscular endurance, strength, bone, and muscle mass. So, not only is performing hundreds of repetitions unnecessary, it can be a quick way to a repetitive strain or overuse injury.
The researchers in a study of BODYPUMP participants worried that doing so many repetitions could result in some improper technique.
Not to mention the lack of functional movement involved in a repetitive workout like this. How often during a normal day do you lift something very light over your head 133 times in a row? On the other hand, how often do you need to lift something heavy out of a high cupboard and then put it back later?
The researchers in a study that was done specifically on BODYPUMP participants (which I will cover next) were also worried that doing that many repetitions could result in some improper technique (especially near the end of the class). One of the researchers said that she often saw poor form, especially among newcomers, and that the instructors rarely took the time to correct the individuals who were losing focus. I did notice at my local BODYPUMP gym that the instructors offer a 15-minute workshop that newcomers are strongly encouraged to attend at least once.

The BODYPUMP study
As a fitness writer, I rarely have the opportunity to present a study that fits exactly what I am writing about, but this is one of those rare occasions where someone went out and did my work for me.
In this study, 19 untrained but healthy women participated in two BODYPUMP training sessions per week for 12 weeks. The subjects had little to no experience with weight training and no training program at all for the six months leading up to the study.
Researchers took these measurements at the beginning and end of the study:

Maximal isotonic strength (4-repetition maximal squat)
Incremental test to exhaustion on a treadmill (for blood lactate threshold and maximal aerobic speed)
5-second maximal isometric voluntary contractions for knee extension and trunk extension\
Blood sample
Heart rate measurement
Electromyographic recording (which measures the electrical activity produced by skeletal muscles)
Anthropometric assessment (height, body mass, body fat measured by skinfold)
All 19 women took the same BODYPUMP class taught by the same instructor. The weight of the SmartBar given to the women at the beginning of the study was 10% of their 1RM squat weight. After two weeks, the weight on the bar was increased by 5%. It was increased again by 5% every two weeks.
After the 12 weeks, the results looked like this:

No changes in body weight or body fat
No changes in blood lactate threshold
No changes in maximal aerobic speed
33% improvement in squat strength
Increased isotonic strength
Lowered heart rate
So, what I take away from this is that the women got 33% better at doing squats (which was attributed to neural adaptations, not changes in muscle mass), they saw some improvement in fitness markers (which you would see in any sedentary participants that take up an exercise regimen), and not much else. Not exactly stunning results.

What I like about BODYPUMP
Group training is fun and sweating to music can give you a boost beyond the training itself.
Because you choose your own weight, this class can be for everyone regardless of age, gender, or experience. Although, certain injuries, mobility limitations, or other conditions could prevent you from participating in parts of the workout.
Although their website promises that you will “burn up to 560 calories during a 55-minute BODYPUMP workout” (which is dubious at best) they immediately change the focus of their marketing to “sculpting the body” rather than “losing weight.” As someone who spends much of his life preaching the wonderful health benefits of movement outside of weight loss, this makes me breathe a sigh of relief. You create a strong and capable body by moving it. It would appear that Les and I share this belief.
Much like Orangetheory Fitness the same workout is done around the world. If you like consistency and you happen to travel a lot, or you have a training partner on the other side of the globe, this could come in handy.

Is BODYPUMP good for beginners?
Is BODYPUMP a good workout for beginners? Sure. Taking any class like this is definitely a good way to get introduced to a variety of resistance training exercises, especially if you opt to take the 15-minute introductory technique class. And I definitely suggest you do that!
The BODYPUMP session moves quickly. If you don’t take the time to learn the movements in a controlled fashion ahead of time, you could easily find yourself floundering, frustrated, and at risk for injury.

What I don’t like about BODYPUMP
Like I said earlier, whether you are doing low reps with heavy weights or high reps with light weights, in order to put on muscle and get that “toned” look, you must lift to failure. I don't know about you but I would find it hard to estimate how heavy my SmartBar needs to be to lift to failure in a class that is 800 reps long.
Unless you have the focus and attention span of a ninja, doing 133 repetitions of anything is going to lead to sloppy form, and sloppy form leads to injury.
Unless you have the focus and attention span of a ninja, doing 133 reps of anything is going to lead to sloppy form and that leads to injury.
Although the movements and exercises are mainly multi-joint they are not very practical, functional, or useful in real life. Unless you are planning to pick up the same can of beans 133 times in a row.
I immediately get my back up when the word bulky is thrown around as being something to be avoided. First of all, bulking-up is not something that happens by accident because you chose the wrong class at the gym. Second, becoming “toned” is really just a combination of adding some mass (or bulk) to your muscles and losing some body fat to increase the definition of those muscles. I know it is just semantics but it bothers my inner coach.

How often should you do BODYPUMP?
As I mentioned earlier, the makers of BODYPUMP suggest doing the workout two or three times a week—mixed in with one of the other Les Mills cardio workouts—whether you're doing it as a class or at home. But as you can probably guess by now, I wouldn’t suggest spending that amount of your precious workout time with this workout.
If you really enjoy it, and doing a BODYPUMP class is really the thing that gets you out of bed in the morning, then it's fine to do a class once every seven to ten days.

If you really enjoy it, and doing a BODYPUMP class is really the thing that gets you out of bed in the morning, then it's fine to do a class once every seven to ten days. More than that, and it could start to cause overuse issues. And, as the study showed, even the participants who were doing BODYPUMP twice per week for 12 full weeks barely saw any meaningful results.
I am all in favor of anything that gets people moving more, and BODYPUMP sounds like a fun way to do that. Mixed in with other classes, activities, and a generally active lifestyle, I don't see a problem with attending the occasional BODYPUMP class.

The verdict
If I had a rating scale for the risk of injury from “too much, too soon” with a dash of “too repetitive,” BODYPUMP might just bump CrossFit out of the top position. Eight-hundred reps are just too many.

The popular low-weight, high-rep BODYPUMP resistance workout claims to have science in its corner. Do those claims hold up to independent research?

After doing some undercover investigation into the Orangetheory Fitness gym chain, I received a flurry of email requests from listeners to look into other new gym fads like Pure Barre, Soul Cycle and BODYPUMP. So today, thanks to listeners Susan and Alyssa, I once again don my fake nose and mustache to get to the bottom of BODYPUMP.
The owner and creator of BODYPUMP (and yes, it is supposed to be in all-caps) is Les Mills who provides group fitness and team training programs for gyms all over the world. Les Mills offers strength, plyo, cardio, weights, martial arts, indoor cycling, and 30-minute high-intensity interval training all set to a custom playlist of music. They also sell clothing, workout equipment, music, and snacks. The company was founded in 1968 and is based in Auckland, New Zealand.

What is the BODYPUMP workout?
In a nutshell, BODYPUMP is a 30-, 45-, or 55-minute resistance workout that uses a barbell with very light weights and very high reps. Their theory behind the combo of lightweight and high reps is to “exhaust your muscles so you don’t get bulky, you just get strength and tone.” That makes very little sense if you break it down. Bodybuilders exhaust their muscles and so do marathon runners, but you couldn’t find two more diverse body types if you tried.

During the workout, you go through five or six specific exercises, in different combinations, and end up completing approximately 800 to 1000 reps in one 55-minute session. The BODYPUMP website says “The secret to BODYPUMP is The Rep Effect—a breakthrough in resistance training that helps create long, lean muscles and a toned, strong physique.” I'll get into the science behind this so-called Rep Effect later.
The exercises you can expect at a BODYPUMP workout are:

Chest Press
Squat
Deadrow
Clean and Press
Lunge
Reverse Curl
To complete the minimum of 800 reps, each exercise will have to be done 133 times during the workout. As they say in New Zealand, "That's a lot of reps, mate!" Having watched pretty much all the videos on the BODYPUMP website, it looks to me like there's a lot (and I do mean a lot) of Clean and Press going on.
Obviously, people who are new to BODYPUMP won’t start at 800 reps, they will work up to this. Or at least, they should. (Too much, too soon, anyone?)
Music is a big part of the BODYPUMP workout and each exercise is done to the rhythm of a particular song. The program has specific music tracks for all levels and the tempo increases as the class continues. For that reason, beginners are encouraged to only do the first few songs while veteran pumpers will do them all.
Music is a big part of the BODYPUMP workout and each exercise is done to the rhythm of a particular song.
An enterprising thing about BODYPUMP is that it's taught in most locations around the world as a group class but you can also buy the music tracks and SmartBar (their branded barbell) and do the program at home. Doing the workout two or three times a week, mixed in with one of the other Les Mills cardio workouts, is what they recommend, whether you are doing it as a class or at home.
The BODYPUMP website says “This full-body barbell workout will burn calories, shape, and tone your entire body, increase core strength and improve bone health.” I agree that many of the exercises involved in BODYPUMP are multi-joint and use many muscle groups. As you can read about in the article 10 Tips to Build Muscle Fast, this is one of the best ways to get fit. Single joint movements like biceps curls or triceps extensions do not build muscle quickly. Multi-joint exercises like cleans, deadlifts, and squats not only work more muscles in less time, but they also allow you to use a much heavier weight than you can lift with single-joint exercises. But that isn’t important here since the whole idea is to use a light weight.

The science (or lack of) behind the rep effect
The BODYPUMP website also says “This program is based on THE REP EFFECT, a proven formula that exhausts muscles using light weights, while performing high repetitions - this is the secret to developing lean, athletic muscle.” However, that exhausted and burning feeling you get from doing all those reps is likely just lactic acid building up faster than it can be flushed from your muscles. And although that is a marker of working hard, it doesn’t necessarily mean that the muscle is getting lean or more athletic.
As far as their claim of not bulking up and only developing these “lean athletic muscles,” (I’d like to know which muscles they consider to be non-athletic) that doesn’t make much sense either. In a rather famous study from 2015, the last nail was put in the coffin as to whether high reps with low weight or low reps with high weight developed more muscle mass. And it was a draw!
In the study, 18 young men, who were experienced in Resistance Training, were matched according to their baseline strength and then randomly assigned to one of two groups:

A low-weight routine where 25-35 repetitions were performed per set per exercise
A high-weight routine where 8-12 repetitions were performed per set per exercise
The findings indicated that both ways of training—"to failure," which is when you can’t manage to lift the weight one more time—can elicit significant increases in muscle hypertrophy (muscle building). The only difference was that the high weight training turned out to be better for maximizing strength gains.
So, if you want to create muscle, you can do it either way. But if you want to get strong, you need heavy weights with low reps.
Huh. So the BODYPUMP definition of the rep effect is a little questionable, but at least we know you will put on some muscle doing this workout. That's assuming you don’t choose such a light weight that you don’t get to failure even by the end of the 800 reps.

The risk of too many reps
The makers and promoters of BODYPUMP insist that muscular endurance is built by doing many repetitions of each exercise. But research shows that simply doing eight to 12 reps also develops muscular endurance, strength, bone, and muscle mass. So, not only is performing hundreds of repetitions unnecessary, it can be a quick way to a repetitive strain or overuse injury.
The researchers in a study of BODYPUMP participants worried that doing so many repetitions could result in some improper technique.
Not to mention the lack of functional movement involved in a repetitive workout like this. How often during a normal day do you lift something very light over your head 133 times in a row? On the other hand, how often do you need to lift something heavy out of a high cupboard and then put it back later?
The researchers in a study that was done specifically on BODYPUMP participants (which I will cover next) were also worried that doing that many repetitions could result in some improper technique (especially near the end of the class). One of the researchers said that she often saw poor form, especially among newcomers, and that the instructors rarely took the time to correct the individuals who were losing focus. I did notice at my local BODYPUMP gym that the instructors offer a 15-minute workshop that newcomers are strongly encouraged to attend at least once.

The BODYPUMP study
As a fitness writer, I rarely have the opportunity to present a study that fits exactly what I am writing about, but this is one of those rare occasions where someone went out and did my work for me.
In this study, 19 untrained but healthy women participated in two BODYPUMP training sessions per week for 12 weeks. The subjects had little to no experience with weight training and no training program at all for the six months leading up to the study.
Researchers took these measurements at the beginning and end of the study:

Maximal isotonic strength (4-repetition maximal squat)
Incremental test to exhaustion on a treadmill (for blood lactate threshold and maximal aerobic speed)
5-second maximal isometric voluntary contractions for knee extension and trunk extension\
Blood sample
Heart rate measurement
Electromyographic recording (which measures the electrical activity produced by skeletal muscles)
Anthropometric assessment (height, body mass, body fat measured by skinfold)
All 19 women took the same BODYPUMP class taught by the same instructor. The weight of the SmartBar given to the women at the beginning of the study was 10% of their 1RM squat weight. After two weeks, the weight on the bar was increased by 5%. It was increased again by 5% every two weeks.
After the 12 weeks, the results looked like this:

No changes in body weight or body fat
No changes in blood lactate threshold
No changes in maximal aerobic speed
33% improvement in squat strength
Increased isotonic strength
Lowered heart rate
So, what I take away from this is that the women got 33% better at doing squats (which was attributed to neural adaptations, not changes in muscle mass), they saw some improvement in fitness markers (which you would see in any sedentary participants that take up an exercise regimen), and not much else. Not exactly stunning results.

What I like about BODYPUMP
Group training is fun and sweating to music can give you a boost beyond the training itself.
Because you choose your own weight, this class can be for everyone regardless of age, gender, or experience. Although, certain injuries, mobility limitations, or other conditions could prevent you from participating in parts of the workout.
Although their website promises that you will “burn up to 560 calories during a 55-minute BODYPUMP workout” (which is dubious at best) they immediately change the focus of their marketing to “sculpting the body” rather than “losing weight.” As someone who spends much of his life preaching the wonderful health benefits of movement outside of weight loss, this makes me breathe a sigh of relief. You create a strong and capable body by moving it. It would appear that Les and I share this belief.
Much like Orangetheory Fitness the same workout is done around the world. If you like consistency and you happen to travel a lot, or you have a training partner on the other side of the globe, this could come in handy.

Is BODYPUMP good for beginners?
Is BODYPUMP a good workout for beginners? Sure. Taking any class like this is definitely a good way to get introduced to a variety of resistance training exercises, especially if you opt to take the 15-minute introductory technique class. And I definitely suggest you do that!
The BODYPUMP session moves quickly. If you don’t take the time to learn the movements in a controlled fashion ahead of time, you could easily find yourself floundering, frustrated, and at risk for injury.

What I don’t like about BODYPUMP
Like I said earlier, whether you are doing low reps with heavy weights or high reps with light weights, in order to put on muscle and get that “toned” look, you must lift to failure. I don't know about you but I would find it hard to estimate how heavy my SmartBar needs to be to lift to failure in a class that is 800 reps long.
Unless you have the focus and attention span of a ninja, doing 133 repetitions of anything is going to lead to sloppy form, and sloppy form leads to injury.
Unless you have the focus and attention span of a ninja, doing 133 reps of anything is going to lead to sloppy form and that leads to injury.
Although the movements and exercises are mainly multi-joint they are not very practical, functional, or useful in real life. Unless you are planning to pick up the same can of beans 133 times in a row.
I immediately get my back up when the word bulky is thrown around as being something to be avoided. First of all, bulking-up is not something that happens by accident because you chose the wrong class at the gym. Second, becoming “toned” is really just a combination of adding some mass (or bulk) to your muscles and losing some body fat to increase the definition of those muscles. I know it is just semantics but it bothers my inner coach.

How often should you do BODYPUMP?
As I mentioned earlier, the makers of BODYPUMP suggest doing the workout two or three times a week—mixed in with one of the other Les Mills cardio workouts—whether you're doing it as a class or at home. But as you can probably guess by now, I wouldn’t suggest spending that amount of your precious workout time with this workout.
If you really enjoy it, and doing a BODYPUMP class is really the thing that gets you out of bed in the morning, then it's fine to do a class once every seven to ten days.

If you really enjoy it, and doing a BODYPUMP class is really the thing that gets you out of bed in the morning, then it's fine to do a class once every seven to ten days. More than that, and it could start to cause overuse issues. And, as the study showed, even the participants who were doing BODYPUMP twice per week for 12 full weeks barely saw any meaningful results.
I am all in favor of anything that gets people moving more, and BODYPUMP sounds like a fun way to do that. Mixed in with other classes, activities, and a generally active lifestyle, I don't see a problem with attending the occasional BODYPUMP class.

The verdict
If I had a rating scale for the risk of injury from “too much, too soon” with a dash of “too repetitive,” BODYPUMP might just bump CrossFit out of the top position. Eight-hundred reps are just too many.