Doing arm extensions only in the middle part of the motion makes your triceps grow more than doing the full motion.
Scientific Claim
Partial range of motion performed in the middle part of the movement is associated with greater triceps brachii hypertrophy than full range of motion, with a between-group effect size of 1.21.
Original Statement
“pROM in the middle part of the ROM elicited greater triceps brachii hypertrophy than fROM (between-group ES: 1.21).”
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 'elicited greater' implying causation, but the design of included studies is 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 middle ROM consistently produces superior triceps hypertrophy compared to full ROM.
Whether middle ROM consistently produces superior triceps hypertrophy compared to full ROM.
What This Would Prove
Whether middle ROM consistently produces superior triceps hypertrophy compared to full ROM.
Ideal Study Design
A systematic review and meta-analysis of 10+ RCTs comparing middle ROM (45–90°) vs. full ROM (0–120°) in triceps extensions (skull crushers, overhead extensions), measuring triceps muscle thickness via ultrasound in healthy adults at 8–12 weeks, with matched volume and intensity.
Limitation: Cannot determine if benefit is due to peak tension or muscle length.
Randomized Controlled TrialLevel 1bCausal effect of middle ROM on triceps hypertrophy.
Causal effect of middle ROM on triceps hypertrophy.
What This Would Prove
Causal effect of middle ROM on triceps hypertrophy.
Ideal Study Design
A double-blind RCT of 45 adults performing 12 weeks of triceps extensions, randomized to middle ROM (45–90°) or full ROM (0–120°), with muscle cross-sectional area measured via MRI at baseline and endpoint, controlling for training experience.
Limitation: Limited to young, healthy participants; may not apply to older adults.
Prospective Cohort StudyLevel 2bLong-term association between preferred triceps ROM and hypertrophy in real-world training.
Long-term association between preferred triceps ROM and hypertrophy in real-world training.
What This Would Prove
Long-term association between preferred triceps ROM and hypertrophy in real-world training.
Ideal Study Design
A 2-year cohort of 120 resistance-trained individuals tracking their preferred ROM in triceps exercises, with ultrasound measurements of triceps thickness at 6, 12, and 24 months, adjusting for training volume and diet.
Limitation: Cannot rule out self-selection bias in ROM choice.
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 triceps exercises with a partial motion in the middle of the movement made the muscle grow more than doing the full motion, and the numbers match exactly what the claim says.