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Dr. Keith Baar On Single Versus Multiple Sets And Training To Failure

A friend recently shared with me an interview on the We Do Science podcast with Dr. Keith Baar from the physiology dept at UC Davis where he discusses the effectiveness of training with a single set to failure versus multiple sets. The first twenty minutes of the podcast focuses mainly on mTOR and hypertrophy, but a little after the twenty three minute mark the interview turns to the subject of one set versus three or five, and training to muscular failure. Although Dr. Baar isn’t saying anything I haven’t told you before (as a general rule you should perform one set per exercise to the point of momentary muscular failure) I find it interesting to hear other people’s take on it  and I think you will too: 

Laurent Bannock: …let’s go back to the training stress then. Lots of people talk about, well, lots of people argue about whether or not it’s important to exert a certain level of mechanical stress, not necessarily to failure, but some people argue that you do need to take it to failure, and I believe you have an opinion based on the research that you can present to us on that.

Dr. Baar: Yeah, so, the idea of the training load and how much training you need to do or how much sets you need to do, all of those things, again this is massively controversial. If you look back on the whole research of the sets and the physiological response and the muscle growth and the strength improvement with one, two, three, up to five sets, there’s only one paper that claims that there’s a difference between doing three sets, and doing five sets, or doing one set. That’s an early paper by Berger (1), and if you go back and look at the data his conclusions say three sets are better than one but if you look at the data there’s absolutely no difference between three sets and one set or five sets.

One set of an exercise or three?

Berger isn’t the only one claiming this, but the majority of research comparing single and multiple sets does not show a significant difference in results (2, 3, 4). If you are training intensely enough, one set is not only as good as three or more sets for muscular strength and size increases, it is better because in the long run you’re less likely to overtrain and it will save you both time and wear and tear on your body; it gives you both a greater return on the time and effort you invest and a lower risk.

Dr. Baar: And so, you know, some people have challenged him on this and his comeback was that, well, you know, if I had said that one set was as good as three all of these practitioners would have come at me and said that I was wrong. Well, that’s not science, that’s just cowardice.

If you go back and you look, people who really believe that three sets are better, Stu Phillips believes that three sets are better than one, he published a really nice study where he showed sure enough you can get a little bit more hypertrophy but that’s because it was a relatively short study. Strength gains were exactly the same whether you did three sets of 80% or one set of 80%. So, what we’re learning is that it’s not important necessarily, what your volume is, what the volume of load is. It looks like what’s important is that you apply a load, and that you apply that load to failure.

If you’re only looking for muscle growth you can do it at 30%, 40%, whatever. Bodybuilders traditionally have done this where they lift a light weight lots of times they get to failure, muscle still grows nicely. If you want to grow strength rather than muscle size, so if you want to grow both strength and size together, now what you have to do is you have to lift a heavier weight to failure. If you are doing an exercise that you can get to failure then one set’s enough. So if you’re doing an exercise in a machine and you can do say, a leg press and you can get all the way to momentary muscular failure where you can’t press the weight up and even you can’t resist the weight in the negative direction, that’s what we call momentary muscular failure, one set is going to be sufficient to activate all the hypertrophic stimuli.

As I’ve explained elsewhere, although some people may respond better to higher loads and lower reps or time under load (TUL) and others to lower loads and higher reps or time, in the long run load has less to do with your muscular strength and size gains than your intensity of effort. If you value your long term joint health and functional ability though, you should not use loads that are too heavy for you to maintain reasonably good form for the full duration of an exercise. Also, although going to the point of eccentric muscular failure would definitely ensure you’ve recruited and effectively stimulated all the motor units in the targeted muscles if you do this on a regular basis for most or all of your exercises it can also be harder for some people to recover from.

Dr. Baar: If you’re doing a different exercise, say you’re doing a snatch, or say a squat, or a clean, where because of the small muscles that you need to have active in order to complete the exercise there’s no way that you can get your big muscles to failure, now what you have to do is you have to add subsequent sets because one set, you can’t get close to failure. You can only produce the motion then the small muscles of your back or the muscles of your grip are going to fail. So you need to come back with another set, and another set, and another set until you get closer and closer to failure. We know that because if you do, like I said the 30%, so you do a lower weight, and you do it to failure you get a hypertrophic stimulus, we know that because if you do blood flow restriction and you do a resistance exercise you get closer to failure.

This depends on how you perform the exercise. Unfortunately, the way most people perform many exercises this can be a problem. Fortunately, it is possible for you to safely perform exercises like squats and deadlifts to failure without the smaller muscles of the lower back or grip becoming a limiting factor if you know what you’re doing (I do not recommend snatches or cleans for anyone other than competitive weightlifters, however, since they provide no general physical benefits you can’t obtain more safely and effectively with other exercises). If you squat with sufficient depth and proper turnaround technique and you avoid locking out much less load is required and your back will not be a limiting factor. The same goes for deadlifts if you avoid setting the weight down between reps and use proper turnaround technique. However, if your grip is still a limiting factor during deadlifts you can work around it using straps or hooks (but not until after your grip starts to fail) and perform additional direct exercises to strengthen your grip.

This also has a lot to do with your mental focus. You’ll find you can reach failure with the target muscles in compound exercises like squats and deadlifts if you make a conscious effort to feel and focus on intensely contracting them rather than just thinking about making the weight go up and down. Remember, an exercise is something you do to your muscles with the weight, not something you do to the weight with your muscles.

Dr. Baar: So, the reason for this, the reason that there is this distinction is because in humans we don’t recruit all of the muscle fibers within our muscle except when we get to failure. So, when you’re not at failure you haven’t produced the load across all of the muscle fibers and as a result you are not getting activation of the signaling pathways in every muscle fiber, and specifically not in the biggest muscle fibers because the way that you work is you start with the smallest motor units that are going to be able to do the exercise, and if you don’t go to failure only those small units get activated, and those aren’t the ones you’re trying to activate by really pushing yourself to failure. As you get to failure you have to recruit bigger and bigger motor units until you’ve recruited every motor unit within the muscle and now every unit within the muscle has felt the load. As a result you get the stimulus across every motor unit. That’s true if you’re doing blood flow restriction, if you’re doing a low weight to failure, no matter how you do it what you’re trying to do is get the load across each muscle fiber.

Although you may have recruited all the motor units in the targeted muscles before you achieve momentary muscular failure, it is better for you to go all the way just to be sure. Then, after you think you’ve achieved momentary muscular failure keep contracting the targeted muscles as hard as you can for at least five more seconds to be really sure.  If you’ve still got doubts or questions about training to momentary muscular failure read some of my other articles on the subject:

Q&A: Training To Momentary Muscular Failure

Q&A: Criticisms Of Training To Failure

Poor Form Causes Injuries, Not Training To Failure


  1. Berger RA. Effect of varied weight training programs on strength. Res Q1962;33:168–81.
  2. Carpinelli RN. Berger in retrospect: effect of varied weight training programmes on strength. Br J Sports Med2002;36:319–24.
  3. Carpinelli RN, Otto RM, Winett RA. A Critical Analysis of the ACSM Position Stand on Resistance Training: Insufficient Evidence to Support Recommended Training Protocols. Journal of Exercise Physiology Online 2004;7(3):1-60
  4. Fisher J, Steele J, Bruce-Low S, Smith D. Evidence Based Resistance Training Recommendations. Medicine Sportiva Med Sport 01/2011; 15:147-162.
  5. Who wrote and created this blog post and information is here :
  6. Listen to the podcast by Dr. Keith Baar : that 1 set is better than multiple