If you’ve been following our site, you probably know that you can achieve optimal muscle growth with both low-rep (heavy weight) and high-rep (light weight) training; if not, check out this article. But which of these two approaches is the most taxing, or in other words, requires the most recovery time?

RESEARCH

You might think that training with heavy weights is the most taxing. However, research shows the opposite: training at lower intensities leads to more neuromuscular fatigue, strength loss, and recovery time than training at high intensity, assuming that in both cases you train to near failure.

HEAVY CARDIO

It may sound a bit contradictory, but compare it yourself: a set of squats with 30 reps to near muscle failure versus a set with a heavy weight with which you can do 3 reps. The set of 30 reps will feel like heavy cardio and your set will probably fail several reps before muscle failure due to the high cardiovascular fatigue. With a short set of 3 reps, that fatigue is hardly there and it doesn’t have to be, because it is primarily the mechanical tension that counts for muscle growth, or the growth stimulus that arises from a few heavy reps to near muscle failure.

A little calculation shows how this happens. If we assume a 1RM of 100 kg, the total weight after the 3RM is only 90 kg × 3 = 270 kg. After the 30RM it is 30 kg × 30 = 900 kg. Your muscles have therefore performed more than 3x more physical work.

BENEFITS OF HIGH REP

Does this mean that high rep work for muscle growth is a thing of the past? Not entirely. The big advantage of training with light weights is that they are gentle on your joints and other connective tissue. Useful if you have (had) an injury. In addition, training with many repetitions creates metabolic stress, which in itself could be a path to muscle growth. See also this article. Finally, you burn more calories with long sets. However, we believe that fat burning should primarily occur as a result of a calorie deficit, possibly supplemented with cardio (“Don’t lift to lose fat”).

ADVICE

Fortunately, in practice you don’t have to choose: you can do both high-rep and low-rep in one training program.

Our advice? Start with 6-15 reps (6-10 for compounds, 10-15 for isolation exercises). This is 80% of your training. In addition, you do 10% high-rep sets (15-30 reps) and 10% low-rep work (3-6 reps). This way you have the best of three worlds.