According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Randomized Controlled Trial (RCT) with isolated metabolic stress induction
Test whether inducing metabolic stress (via controlled lactate infusion, acidosis, or phosphate elevation) without mechanical tension or muscle damage leads to muscle hypertrophy in healthy humans. Within-subject crossover trial with unilateral metabolic stress manipulation
Compare hypertrophy in one limb exposed to metabolic stress alone versus the contralateral limb exposed to mechanical tension alone. Longitudinal observational study with metabolic biomarker tracking
Determine if individuals with consistently higher post-exercise metabolic stress markers show less hypertrophy than those with lower markers, when mechanical load is held constant. In vivo human muscle biopsy study with signaling pathway analysis
Assess whether metabolic stress markers directly activate known hypertrophy pathways (e.g., mTOR, S6K, p70S6K) in human muscle tissue in the absence of mechanical tension. Meta-analysis of training studies comparing metabolic vs. mechanical stress dominance
Synthesize existing RCTs to determine if training protocols designed to maximize metabolic stress (e.g., BFR, high-rep, short rest) produce less hypertrophy than those maximizing mechanical tension (e.g., heavy load, long rest), when volume is equated.