How much your butt muscles 'fire up' during your first hip thrust or squat doesn’t tell you how much they’ll grow over time — the feeling during the workout isn’t a reliable guide to results.
Scientific Claim
Acute surface electromyography (sEMG) amplitude during the first training session does not predict long-term gluteus maximus or medius hypertrophy outcomes in untrained individuals, as correlations between initial muscle activation and subsequent growth were negligible to weak across all gluteal regions.
Original Statement
“All measured gluteal sites showed greater mean sEMG amplitudes during the first bout hip thrust versus squat set, but this did not consistently predict gluteal hypertrophy outcomes... Across-subject correlations... were negligible to moderate.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The study used multiple rigorous analytical methods to test sEMG as a predictor and found no significant relationship. The definitive language 'does not predict' is justified by the comprehensive analysis and null results.
Evidence from Studies
Supporting (1)
Hip thrust and back squat training elicit similar gluteus muscle hypertrophy and transfer similarly to the deadlift
Even though one exercise made the glutes fire more strongly the first time, that didn’t mean those muscles grew more over time — both exercises led to similar growth, so initial muscle activity doesn’t tell you who will grow bigger.