A new narrative review has critically examined and debunked several widely held but poorly supported theories about what truly causes muscle growth.
The research dispels three major myths: that post-workout hormone spikes are a primary factor, that the 'pump' directly causes growth, and that metabolic stress (the burn) leads to hypertrophy. Evidence shows these have weak or no direct causal link to increasing muscle size.
Instead, the review identifies mechanical tension—applying sufficient resistance through challenging exercise with good form—as the fundamental and primary driver of muscle growth. This principle emphasizes progressive overload over chasing optimal hormonal environments or complex routines.
The findings suggest that foundational, consistent strength training principles are more effective than following fleeting fitness trends or unproven optimization techniques.