The Claim
In untrained young adults, 8 weeks of knee extension training performed with either a 2-second or 4-second eccentric tempo results in similar overall quadriceps hypertrophy and no meaningful difference in 1RM strength gains.
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.
If you're a young adult who hasn't trained before and you do leg extensions slowly—either taking 2 seconds or 4 seconds to lower the weight—your thigh muscles will grow about the same amount, and you'll get just as strong either way.
See the scientific wording
In untrained young adults, 8 weeks of knee extension training with either a 2-second or 4-second eccentric tempo produces similar overall quadriceps hypertrophy and no meaningful difference in 1RM strength gains.
What the research says
1 studyStudy: Effect of different eccentric tempos on hypertrophy and strength of the lower limbs
The study found that doing knee extensions slowly (4 seconds) or faster (2 seconds) on the way down led to almost the same muscle growth and strength gains in young adults after 8 weeks — so the claim is right.
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.