To gain muscle volume, all loads (4, 8, or 12 repetition maximums) are effective, but to maximize strength, it is essential to lift heavy loads.

noli's read

Stuart Phillips, a recognized researcher in exercise physiology, relies here on work (including his own studies, notably an RCT published in the Journal of Applied Physiology) demonstrating that hypertrophy can be achieved across a wide range of repetitions, provided that one goes close to muscular failure. What holds up scientifically is the distinction between volume and strength: while muscle growth is similar with moderate or heavy loads, the neurological adaptation specific to maximal strength is better stimulated by heavier loads (principle of specificity). The potential exaggeration lies in the simplification of the term 'heavy'; for a beginner, the nervous system adapts to varied loads, but for an advanced athlete, the absolute load effectively becomes a limiting factor. There is no evidence that very light loads are superior for volume, but the evidence is solid in confirming that relative intensity (proximity to failure) is the primary driver of growth. The approach is consistent with the current consensus in sports science.

the sources

1. 1Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW 2017
2. 2Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ 2022