The Claim
Motor units are recruited according to the size principle, with smaller units (type I fibers) recruited first and larger units (type II fibers) recruited progressively as fatigue increases and greater force output is required.
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.
Your muscles use smaller, less powerful fibers first when you start moving, and only bring in the bigger, stronger fibers when you need more power or get tired.
See the scientific wording
Motor units are recruited according to the size principle, where smaller units (type I fibers) are recruited first, and larger units (type II fibers) are recruited progressively as fatigue increases and greater force output is required.
What the research says
1 studyThe study looked at how muscles activate fibers in older people and found that smaller fibers still get used first, just like the claim says, so it supports the idea.
Related videos
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.