When you squat or move your legs wide, using a full motion helps your butt and inner thighs grow more than only doing the top half of the movement.
Scientific Claim
Full range of motion is associated with greater muscle hypertrophy in the gluteus maximus and adductors compared to partial range of motion performed in the final part of the movement, with between-group effect sizes of 0.24–0.25.
Original Statement
“fROM elicited greater muscle growth on the gluteus maximus and adductors than pROM in the final part of the ROM (between-groups ES: 0.24–0.25).”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design cannot support claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The term 'elicited greater' implies causation, but the underlying studies' designs are unknown. Only an associative interpretation is valid.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Systematic Review & Meta-AnalysisLevel 1aIn EvidenceWhether full ROM consistently leads to greater gluteal and adductor hypertrophy than final partial ROM across diverse populations and training protocols.
Whether full ROM consistently leads to greater gluteal and adductor hypertrophy than final partial ROM across diverse populations and training protocols.
What This Would Prove
Whether full ROM consistently leads to greater gluteal and adductor hypertrophy than final partial ROM across diverse populations and training protocols.
Ideal Study Design
A meta-analysis of 15+ RCTs comparing full ROM vs. final partial ROM in hip-dominant exercises (e.g., squats, hip thrusts, adductor machines) in healthy adults, measuring muscle thickness via ultrasound or DXA after 8–16 weeks, controlling for volume and load.
Limitation: Cannot determine if differences are due to mechanical tension, muscle stretch, or volume distribution.
Randomized Controlled TrialLevel 1bWhether full ROM causes greater hypertrophy in glutes and adductors than final partial ROM under controlled conditions.
Whether full ROM causes greater hypertrophy in glutes and adductors than final partial ROM under controlled conditions.
What This Would Prove
Whether full ROM causes greater hypertrophy in glutes and adductors than final partial ROM under controlled conditions.
Ideal Study Design
A double-blind RCT with 50 participants randomized to 12 weeks of hip thrusts using either full ROM (0–100%) or final partial ROM (70–100%), matched for sets, reps, and load, with muscle thickness measured via ultrasound at baseline and endpoint.
Limitation: Cannot assess long-term effects beyond 16 weeks or in older populations.
Prospective Cohort StudyLevel 2bWhether individuals who habitually use full ROM in hip exercises develop larger glutes and adductors over time.
Whether individuals who habitually use full ROM in hip exercises develop larger glutes and adductors over time.
What This Would Prove
Whether individuals who habitually use full ROM in hip exercises develop larger glutes and adductors over time.
Ideal Study Design
A 2-year cohort study tracking 300 resistance-trained individuals who self-select ROM in hip exercises, using video analysis to classify ROM usage and ultrasound to measure muscle growth quarterly.
Limitation: Cannot control for unmeasured confounders like diet, recovery, or genetic predisposition.
Evidence from Studies
Supporting (1)
Which ROMs Lead to Rome? A Systematic Review of the Effects of Range of Motion on Muscle Hypertrophy
The study found that doing full movements (like squatting all the way down) builds more glute and inner thigh muscle than only doing part of the movement at the top, and the numbers match what the claim says.