The Claim

The primary factor explaining the lack of increase in maximal knee extension torque despite rectus femoris muscle lengthening in the supine position is reduced voluntary activation of the knee extensors, rather than increased antagonist co-activation.

Source: The role of agonist and antagonist muscles in explaining isometric knee extension torque variation with hip joint angle

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
20score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

When lying down, your leg muscles don't get stronger even if one key muscle gets longer — and that's mostly because your brain isn't fully turning on those muscles, not because opposing muscles are getting in the way.

See the scientific wording

Reduced voluntary activation of the knee extensors in the supine position, rather than increased antagonist co-activation, is the primary factor explaining why maximal knee extension torque does not increase despite lengthening of the rectus femoris muscle.

What the research says

1 study

  1. Study: The role of agonist and antagonist muscles in explaining isometric knee extension torque variation with hip joint angle

    The study found that people don’t fully use their knee-extending muscles when lying down, even though the muscle is stretched and should be stronger. It’s not because opposing muscles are working too hard—it’s because the brain isn’t activating the main muscles enough.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.