The Claim
The eccentric phase of resistance training contributes significantly to muscle hypertrophy.
What the research says
Roughly balanced
Support and challenge are close. The picture may shift as more studies come in.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Performing the lowering phase of weightlifting exercises leads to greater increases in muscle size compared to other phases of the same exercises.
See the scientific wording
The eccentric phase of resistance training contributes significantly to muscle hypertrophy.
When muscles lengthen under load, they experience high tension that triggers molecular signals to build more contractile proteins and add new nuclei to muscle fibers, making them larger and stronger.
What the research says
4 studiesWhen people lowered weights slowly during squats, their thigh muscles grew more than when they lowered them quickly—even though everything else about the workout was the same. Slowing down the lowering part really helps muscles get bigger.
Lowering weights slowly made muscles grow almost as much as lifting and lowering them together — but lifting alone barely did anything. So the lowering part is what really builds muscle.
The study found that lowering weights (eccentric phase) didn’t make muscles grow bigger — lifting them up (concentric phase) did, especially when combined with protein. So, the claim that lowering weights helps build more muscle isn’t supported by this research.
This study found that lowering weights (eccentric phase) doesn't make your muscles grow much more than lifting them (concentric phase)—both work about the same for building muscle size.
Related videos
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 4 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.