The Claim

In resistance-trained males performing free-weight back squats with maximal intended velocity, the timing of peak electromyographic activation in the gluteus maximus occurs significantly later during the concentric phase when the load is increased to 90% of one-repetition maximum (1-RM) compared to lighter loads of 30%–50% 1-RM, indicating that neuromuscular coordination in hip extensors is modulated by external load.

Source: Comparison of muscle activation and kinematics during free-weight back squats with different loads

What the research says

Challenges is higher

Challenge is ahead, but a single strong supporting study can change this.

Supports
0score
Challenges
21score

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 strong guys do fast squats with heavy weights, their butt muscles kick in later during the upward push compared to when they use lighter weights — it’s like their body adjusts how it uses those muscles depending on how heavy the weight is.

See the scientific wording

In resistance-trained males performing free-weight back squats with maximal intended velocity, the timing of peak activation in the gluteus maximus shifts later in the upward phase as load increases, occurring significantly later at 90% 1-RM compared to 30%–50% 1-RM, suggesting load-dependent neuromuscular coordination in hip extensors.

What the research says

1 study
  1. Study: Comparison of muscle activation and kinematics during free-weight back squats with different loads

    The study looked at when muscles turn on most during squats with different weights, and found that heavier weights don’t change when the glutes reach peak activity, which goes against the claim.

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.