The claimEvidence B · meta-analysis
'Muscle confusion' (rotating exercises) maximizes growth
The evidence
Hypertrophy is driven by progressive overload + total volume; exercise variety ranks far below intensity/frequency.
The mechanism, in brief
Why does muscle grow? Mainly because of three stimuli, and they are far from equal. Get these three straight and your training stops wasting effort.
Sources (2)
- Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 24(10), 2857-2872.
- Morton, R. W., et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376–384. 49 RCTs, 1,863 participants, resistance training of 6 weeks or more. Protein supplementation added 2.49 kg to 1RM and 0.30 kg to fat-free mass; the effect fell with age and was larger in trained people. Break point for FFM gains at 1.62 g/kg/day (95% CI 1.03-2.20; 42 study arms, 723 participants; the biphasic model was not statistically significant, p = 0.079); given the CI, the authors say ~2.2 g/kg/day may be prudent for those maximising gains; timing, post-exercise dose and source play a minor if any role; they cite per-dose MPS break points of 0.24 (younger) and 0.40 g/kg (older). One author reports grant support from the US National Dairy Council (abstract and full text, PMC5867436).