Holding a muscle stretched while pushing against something still makes it grow more than holding it short, even if you don’t move.
Scientific Claim
Isometric contractions performed at longer muscle lengths produce greater muscle hypertrophy than isometric contractions performed at shorter muscle lengths.
Original Statement
“I think it is currently best to consider the isometric data as an entirely separate category. For this reason, I think it is currently best to consider the isometric data as an entirely separate category.”
Context Details
Domain
exercise
Population
human
Subject
isometric contractions at longer muscle lengths
Action
produce
Target
greater hypertrophy than isometric contractions at shorter muscle lengths
Intervention Details
Evidence from Studies
Supporting (1)
Differential changes in muscle architecture and neuromuscular fatigability induced by isometric resistance training at short and long muscle-tendon unit lengths.
This study found that doing muscle exercises while the muscle is stretched out (long length) made the muscle fibers grow longer, which usually means the muscle is getting bigger — while exercises done with the muscle shortened didn’t have the same effect.
Contradicting (2)
The study found that doing isometric exercises with the hamstrings stretched out (long length) and bent (short length) both made the muscles grow just as much — so stretching more doesn’t give you bigger muscles in this case.
Does Muscle Length Influence Regional Hypertrophy? A Systematic Review and Meta-Analysis
The study found that training muscles at longer or shorter lengths doesn’t make a big difference in muscle growth — so stretching your muscle more during a static hold doesn’t help you grow bigger muscles any more than keeping it short.