The Claim
The duration of the eccentric phase of resistance exercise has a negligible effect on muscle hypertrophy in trained individuals, with a Hedge’s g of 0.05 and wide confidence intervals indicating no clear benefit from shorter or longer eccentric phases.
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.
Changing how long the lowering phase of a weightlifting movement lasts does not meaningfully affect muscle growth in people who regularly train.
See the scientific wording
The effect of eccentric phase duration on muscle hypertrophy is uncertain, with a negligible effect size (Hedge’s g = 0.05) and wide confidence intervals, indicating no clear benefit from either shorter or longer eccentric phases for muscle growth in trained individuals.
When muscles are stretched under load, they trigger the same amount of muscle building signals no matter how slowly or quickly the stretch happens. Once the muscle is under enough tension, adding more time doesn't make it build more muscle.
What the research says
1 studyThis study found that whether you lower the weight slowly or quickly during weightlifting, it doesn’t really make a difference in how much your muscles grow — especially if you’re already trained.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.