The Claim
In untrained men performing leg extension exercises twice weekly for 8 weeks at 70% one-repetition maximum, self-selected repetition duration results in similar increases in muscle strength (mean gain: 8–10%) and vastus lateralis muscle cross-sectional area (mean gain: 7–10%) compared to controlled repetition duration (2s concentric, 2s eccentric), despite lower time under tension per repetition (1.7–1.8s vs. 4.0s) and higher total volume load.
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.
In untrained men doing leg extensions twice a week for eight weeks at 70% of their maximum lift, choosing their own lifting speed produces the same increases in muscle strength and thigh muscle size as using a fixed speed, even though each repetition involves less total time under tension and more total repetitions.
See the scientific wording
In untrained men performing leg extension exercises twice weekly for 8 weeks at 70% one-repetition maximum, self-selected repetition duration produces similar increases in muscle strength (mean gain: 8–10%) and vastus lateralis muscle cross-sectional area (mean gain: 7–10%) as controlled repetition duration (2s concentric, 2s eccentric), despite significantly shorter time under tension per repetition (1.7–1.8s vs. 4.0s) and higher total volume load.
When muscles are worked hard near failure, the force they generate and the buildup of metabolic byproducts trigger signals that tell muscle cells to grow bigger and stronger, regardless of how fast or slow the movements are done, as long as the total amount of work is high enough.
What the research says
1 studyFor guys new to lifting, lifting weights at their own speed gives the same muscle and strength gains as lifting slowly, as long as they do about the same total amount of work and push themselves close to failure.
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.