Doing exercises through a full motion or starting the movement with a shorter motion (but not ending with it) helps your muscles grow more in your thighs and biceps than doing only the last part of the movement.
Scientific Claim
Full range of motion and partial range of motion performed in the initial part of the movement are associated with greater muscle hypertrophy in the rectus femoris, vastus lateralis, biceps brachii, and brachialis distal sites compared to partial range of motion performed in the final part of the movement, with between-group effect sizes of 0.20–0.90.
Original Statement
“Full ROM and pROM performed in the initial part of the ROM elicited greater muscle hypertrophy of the rectus femoris, vastus lateralis, biceps brachii, and brachialis distal sites (between-groups ES: 0.20–0.90) than pROM performed in the final part of the ROM.”
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 abstract uses language implying superiority ('elicited greater'), but the included studies' designs are unknown, so causation cannot be established. Only association is supported.
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 ROM patterns (full vs. initial partial vs. final partial) consistently associate with differential hypertrophy in specific muscles across diverse populations and protocols.
Whether ROM patterns (full vs. initial partial vs. final partial) consistently associate with differential hypertrophy in specific muscles across diverse populations and protocols.
What This Would Prove
Whether ROM patterns (full vs. initial partial vs. final partial) consistently associate with differential hypertrophy in specific muscles across diverse populations and protocols.
Ideal Study Design
A systematic review and meta-analysis of at least 20 randomized controlled trials in healthy adults aged 18–40, comparing full ROM, initial partial ROM (0–50% of excursion), and final partial ROM (50–100% of excursion) for squats, leg extensions, bicep curls, and preacher curls, with muscle thickness measured via ultrasound at 12+ weeks, controlling for volume, load, and training experience.
Limitation: Cannot prove causation if included RCTs lack blinding or have high dropout rates.
Randomized Controlled TrialLevel 1bWhether initial partial ROM causes greater hypertrophy than final partial ROM in specific muscles under controlled conditions.
Whether initial partial ROM causes greater hypertrophy than final partial ROM in specific muscles under controlled conditions.
What This Would Prove
Whether initial partial ROM causes greater hypertrophy than final partial ROM in specific muscles under controlled conditions.
Ideal Study Design
A double-blind, crossover RCT with 40 healthy young adults performing 12 weeks of supervised resistance training using either initial partial ROM (0–50%) or final partial ROM (50–100%) for leg extensions and bicep curls, with muscle thickness via DXA as primary outcome, matched for volume and load.
Limitation: Cannot generalize to untrained, elderly, or clinical populations without additional studies.
Prospective Cohort StudyLevel 2bWhether habitual use of certain ROM patterns predicts long-term muscle growth in real-world training environments.
Whether habitual use of certain ROM patterns predicts long-term muscle growth in real-world training environments.
What This Would Prove
Whether habitual use of certain ROM patterns predicts long-term muscle growth in real-world training environments.
Ideal Study Design
A 1-year prospective cohort of 200 resistance-trained individuals tracking their typical ROM usage in compound lifts via video analysis and measuring muscle hypertrophy via ultrasound every 3 months, adjusting for training volume, nutrition, and recovery.
Limitation: Cannot rule out confounding by training history, diet, or genetics.
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 lifting weights through a full motion or starting with a partial motion (but not ending with it) makes muscles like the biceps and quads grow more than doing partial motion only at the end. So yes, the claim is right.