The Claim
When training volume and effort are matched, the total muscle mass recruited during a compound exercise does not result in a greater magnitude of hypertrophy in a target muscle compared to an isolation exercise targeting the same muscle.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
When the total amount of work and effort are the same, lifting weights that engage multiple muscles at once does not lead to more muscle growth in a specific muscle than lifting weights that focus only on that muscle.
See the scientific wording
Total muscle mass recruited during a compound exercise does not determine the magnitude of hypertrophy in a target muscle when compared to an isolation exercise with matched training volume and effort.
When you lift weights to fatigue, your target muscle grows based on how much stress and buildup of waste products it experiences during the workout, not on how many other muscles are working at the same time. Even if a movement uses many muscles, only the muscle being trained directly feels the full stress needed to trigger growth.
What the research says
2 studiesWhen you lift weights with the same total effort and number of reps, it doesn't matter if you're using a move that works many muscles or just one — your target muscle grows about the same.
When people lift weights with the same total effort and number of reps, doing a move that uses many muscles (like leg press) doesn’t make one muscle grow bigger than doing a move that only uses that one muscle (like leg extension).
Related videos
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 2 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.