The Claim

In trained individuals, the subjective sensation of quadriceps contraction during leg extension exercise does not consistently correlate with objective MRI-based T2 changes in the rectus femoris muscle, suggesting that perceived muscle effort may not accurately reflect regional muscle activation as measured by T2 relaxation times.

Source: Hip flexion angle affects longitudinal muscle activity of the rectus femoris in leg extension exercise

What the research says

Supports is higher

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

Supports
44score
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.

Correlation
1 study reviewed
In plain English

Just because your quad feels like it's working hard during leg lifts doesn't mean that part of the muscle is actually lighting up — especially in people who train regularly.

See the scientific wording

Subjective sensation of quadriceps contraction during leg extension exercise does not consistently reflect objective MRI-based T2 changes in the rectus femoris, indicating that perceived muscle effort may not accurately indicate regional muscle activation in trained individuals.

What the research says

1 study
  1. Study: Hip flexion angle affects longitudinal muscle activity of the rectus femoris in leg extension exercise

    The study found that how hard people *felt* their thigh muscles were working during leg exercises didn’t match what the MRI showed was actually happening in different parts of the muscle. This means feeling the burn isn’t always a good sign of which muscle parts are really being worked.

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.