What is the best rep range for building muscle?
How many reps should you do for an exercise in order to build muscle?
For many years, the most commonly accepted method of determining the rep scheme for hypertrophy, strength and endurance is called the "repetition continuum". Essentially, this theory states that depending on your goal(hypertrophy, strength or endurance) there are specific rep ranges to stay within to achieve said goal. This has been the standard way of thinking since 1945. It goes as follows:
For strength, the rep range is between 1-5(using 80%-100% 1RM)
For hypertrophy, the rep range is between 8-12(using 60%-80% of 1RM)
For muscular endurance, the rep range is 15 and over(using less than 60% of 1RM)
The hypertrophy rep range(8-12 reps) is based on the increase of anabolic hormones post workout. Older studies have demonstrated that there are differences in MPS(muscle protein synthesis) when using moderate to low weights.
The science is slowly starting to change, however. More recent studies have shown that even when using low weight on an exercise, there can be a similar increase in post workout MPS as moderate weights, as long as the exercise is completed to failure or near failure, which is something that was not accounted for in the past. Another study in 2016 showed that low weights with rep ranges of 20-25, and moderate weights with rep ranges of 8-12 had similar results in terms of hypertrophy.
How about heavy weight(80%-100%1RM)? When comparing 3 sets of 10 reps(the hypertrophy range) vs 7 sets of 3 reps(the strength range), there were similar results on muscle gain, however, those in the strength range showed signs of joint issues and overtraining, which may not make it as sustainable in the long term.
There was some debate that certain muscle fibers would be better stimulated at heavier loads and others at lighter loads, but current research suggests that that may not be the case, and the difference is negligible.
Using weight below 30% 1RM seems to be the cap though, as the effect on muscle growth goes dramatically downward at that point.
Wow! So what does this all mean?! It means you can build muscle at nearly any rep range! If your main goal is building muscle, there is no need to go very heavy, you can get similar, if not better, results using moderate to low weights. Your main takeaway is that you need to take the muscle to failure, or near failure to cause a hypertrophy response.
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