Body Composition Training 101: Reps

Repetitions (Reps): The number of times you lift the weight in a given set.

Recommendations: 6-15 reps per set


The research and literature regarding adaptations to strength training protocols are quite clear:

  • 1-5 reps are primarily for strength
  • 6-15 reps are primarily for size/development
  • 15+ reps are primarily for muscular endurance

That’s simple enough to apply in the real world, but that’s also the problem. People feel they always need more complicated and revolutionary theories to get results. Trainers and coaches feel the need to invent exotic rep schemes and periodization plans to establish credibility, project value, and remain on the cutting edge.

This problem is compounded by the fact that many consumers are lazy and don’t get results on basic programs because (a) they are not following those programs with any real consistency or (b) they are not working hard enough within those programs to elicit noticeable change. They remain overweight, and bash the program for its ineffectiveness. But the simple, tough love truth is that its not the program, it’s the person.

As a result, consumers feel the need to go outside of basic training parameters and embark on the never-ending search for the magical programs that will produce magical results. They believe any marketing flash and unscrupulous claims, without checking the credibility of those claims. Hence, the market place is flooded with false promises, and training programs that are moving further and further away from the scientific foundations that produce real world results.

If you want to stop chasing infomercial claims and change your physique, you need to get away from the fitness marketing madness, and get back to objective scientific data. Trust me, if you can’t get results busting your ass doing basic exercises with basic set and rep schemes, nothing is going to help you.


The standard three sets of ten training protocol has taken a beating by the so-called “experts” and “innovative” trainers within today’s fitness industry. This is the first rep scheme to get blasted for its archaic and uninformed recommendations. “Oh, that’s so 1980’s” or “What did you just copy that out of a fitness magazine or bodybuilding book?”

Are these jokers frickin’ serious? Three sets of ten falls right within the parameters of optimal training for physique development. Informed and intelligent coaches and trainers that care more about their clients results (and not just making up new crap to sell) actually copied that scheme out of numerous research journals, University labs tests, and anecdotal evidence from thousands of physique athletes who make their living from their physical appearance. Remember, simple on paper does not necessarily mean simple in research and design. E=MC2 encapsulates a lot in one little equation.


Perhaps looking at the physiological responses to OTHER rep ranges will help clarify our stance on the optimal rep ranges specifically designed for physique development. What happens with low rep training, or sets of 1-5 reps? Other than meatheads loading up too much weight on the bar and (a) using terrible form or (b) budging it ¼ inch?

Low rep sets primarily lead to nervous system adaptations. The body becomes more efficient at recruiting the maximum number of motor units possible, and generating incredible amounts of force for a very short period of time. This is all about lifting heavy loads. Now that’s all great for performance-based goals like Powerlifting or Olympic lifting, or showing off at the gym, but what about physique development?

Training for performance is different than training for appearance. There are plenty of lifters who are incredibly strong and can move awe-inspiring loads, but don’t necessarily “look” like they can. I’m sure you can think of a few examples in your gym. There are plenty of overweight powerlifters and underdeveloped Olympic lifters that would make you or I feel like the weights we use might as well be coated in pink plastic. However, their physiques remain less than desirable.

That’s cool. Their goal is not to be a pretty boy or pretty girl, and they would probably gag at the idea of training for cosmetic enhancement. Their goal is to lift heavy shit. The real question is what is your goal? If your goals are to lift heavy shit, than train with 1-5 reps most of the time. But if your goal is to attain a certain look, you need to think outside of that rep zone.

While the body gets better at recruiting more motor units and generating more force, the individual muscle fibers within those motor units do not spend enough time under tension for maximum muscular development. This is why we say 1-5 reps results in primarily neural adaptation, not necessarily muscular adaptations. The latter is what we are after for physique enhancement.

Scott Abel is a physique coach who talks a lot about the difference between training for strength vs. training for development. Here is some of the research he presents on his blog:

And in 1995, David Behm’s research was more direct. His research article “Neuromuscular Implications and Applications of Resistance Training” came to the following sound conclusion so important to those of you interested in developing a better physique: “Maximum strength training methods with their high intensity resistance but low volume of work do NOT elicit substantial muscle hypertrophy.” His research some 10 years later served to reinforce this conclusion as well.

“Therefore a higher volume of work, (greater than 6 reps, with multiple sets) [emphasis and references are his] is needed to ensure a critical concentration of intracellular amino acids to stimulate protein synthesis” (Journal of Strength and Conditioning Research, 1995: p271).


So why not just blast out 50-100 rep sets? Well you can every once in awhile to shock the body, but in general, high rep sets primarily lead to metabolic adaptations. The body becomes more efficient at maintaining aerobic metabolism during higher intensity levels, and increases its lactic acid threshold. In essence, it becomes more fatigue resistant and can do more work without “hitting the wall”.

Again, this is great if your sport requires a certain amount of muscular endurance, but endurance training does not “build” or “shape” a body. For development the muscles need time under (an adequate amount of) tension. The load, or “tension”, is not great enough with ultra high-rep training to produce an adaptive response within the muscle fibers.

You could curl a pencil a thousand times and eventually it would start to burn, but it wouldn’t do much for building your biceps. The resistance is not enough to force the body to tap into its higher threshold, larger motor units; the one’s mostly responsible for growth and development. You just get better at the process of curling, which is meaningless for body composition change.

There is another problem with endurance training for physique development. There are certain “intermediate” muscle fibers within our bodies that can take on either the properties of fast-twitch fibers (power, strength) or the properties of slow-twitch fibers (endurance) depending on training style. Endurance training leads to the conversion of those fibers’ characteristics into the slow-twitch type.

The problem for physique development is that slow-twitch fibers don’t really grow and contribute to gains in overall lean muscle mass. Slow-twitch fibers just get better and more efficient at what they do – maximizing endurance. This is great for performance improvements, but lousy for appearance improvements.

Fast-twitch fibers are the ones that grow and are most responsible for gains in overall lean muscle mass. Emphasizing the development of these fibers is what builds, tones, tightens, and shapes the body, or whatever your particular goal may be. Training in the right rep range — the hypertrophy zone — will maximize lean muscular development. This is can have varying effects on performance depending on your sport, but it is awesome for appearance.

This “conversion factor” is my biggest problem (in terms of physique development) with boot camps, cross-training, circuit training, or any other strength training mode that emphasizes high rep training in a non-stop fashion. What’s happening is the body is building muscular endurance with these plans (and more than likely converting intermediate fibers into the slow-twitch variation) — which is why you feel like you are going to die the first session, but after time you get better at completing the course. Getting better at doing something is a performance adaptation, not an appearance adaptation.

Don’t get me wrong, these workouts are challenging and will kick your ass. But will they build your ass? Will they help you in terms of physique development? There are better, more efficient ways to train if that is your primary goal.

There is this prevailing fitness myth that high reps will help you burn more fat and cut-up. Many people who are primarily concerned with fat loss follow misguided training programs that emphasize ultra-high reps along with non-stop circuit training as their foundation. High reps don’t help you burn fat or rip up. Building muscle (through hypertrophy training) to boost the metabolic rate and maintaining a relative calorie deficit (through proper diet, and maybe some cardio) are the two keys to fat loss. You can’t build muscle with ultra-high reps. If anything you will lose muscle, and end up with a soft/flabby appearance.

The hypertrophy range will indirectly help you burn fat and rip up because building muscle in this range boosts the metabolism and helps you burn more calories — predominantly from fat — at rest. We burn most of our fat at rest, not while we actually train. We burn mostly glucose/glycogen while we train. The damage from this training sets up the environment for fat burning in the recovery process. So to try and burn more fat while training (through cardio or higher reps or cross training or longer duration sessions or “fat burners” or whatever other misguided ideas people have) is a relatively ineffective and inefficient endeavor.

In practical terms, don’t use your weight training sessions to “burn fat”. Let your diet, and to a much lesser extent cardio, burn fat. Always use your weight training sessions to try and build lean muscle. And yes, this includes you ladies. Lean muscle is what shapes your body. You won’t get huge like a guy because of the difference in hormone profiles — testosterone/estrogen ratio. And make no mistake, the overly masculine women you see in bodybuilding mags are taking steroids to change their hormonal profile to resemble a man’s.

This means moderate rep hypertrophy training, not high rep endurance training, is the way to go for both men and women trying to attain a lean, shapely appearance.


Any training will cause somewhat of an adaptive response. You will get some muscle growth training with both low reps (1-5) and high reps (15+). But for the reasons already discussed above, you will not get optimal growth, and will not be maximizing your physique development potential. And as a physique athlete, you want the most effective and efficient training plans to change your physical appearance.

So, we come full circle back to the optimal hypertrophy zone. The majority of your training should fall within the 6-15 rep range if your goals are related to body composition transformation. Here’s what happens in this rep zone:

  • There is adequate tension to force all motor units (small and large) to be recruited.
  • There is adequate time under tension to cause muscular damage, which leads to an adaptive response (growth). Muscle fibers become larger and more dense by increasing the size and number of contractile proteins (called actin & myosin) within those fibers.
  • The area surrounding the muscle is pumped with blood and nutrients, which triggers protein synthesis (and makes you look good in the mirror).
  • You get the greatest acute increases in anabolic hormones: testosterone, growth hormone.


Here’s just a little more science to take this thing home. In Exercise Physiology, there is a principle called the Size Principle of Motor recruitment. This states that:

Motor unit recruitment depends on the force/resistance of the exercise. With light intensity exercise the Type I (slow twitch) motor units are recruited. When the load is increased, the Type IIa (fast twitch) will be recruited with the help of the Type I fibers. When the load becomes even greater, the Type IIb/x will be recruited with the help of the Type IIa and Type I motor units. Therefore Type I motor units are always firing no matter what the intensity. – Jennifer Hill

The hypertrophy zone (6-15) allows this natural neural process to take place. With this rep zone, all of the muscle fibers within a muscle group are recruited (including the one’s that grow the most, the fast twitch varieties) AND those fibers spend enough time under tension for maximum development.

With high reps, only the slow-twitch motor units are recruited. The resistance is not enough to force the higher threshold units (IIa, IIb/x) into action. The problem is, these are the fibers that grow the most, and change a physique.

With low reps (1-5), the tension is great enough to force all of the fibers into action. However, the tension is so great that the body loses its ability to generate force (nervous system fails) before the muscles completely fatigue/exhaust (muscular system fails). Thus, the muscle fibers are not maximally overloaded. They do not spend enough time under tension to cause optimal development.

The take home message is this: Please, just trust me: 6-15 reps is where you should spend most of your time.