Going all the way up and down doesn’t help you build more muscle than just going halfway down and staying in the stretchy part — the stretch is what matters, not the top part.
Scientific Claim
In resistance-trained individuals, the inclusion of short muscle length positions during full range of motion training does not enhance hypertrophy compared to training exclusively at long muscle lengths via lengthened partials, suggesting that the stretched position may be the primary driver of muscle growth.
Original Statement
“The fROM condition observed similar muscle hypertrophy as the pROM condition in the present study, in contrast to previous studies that found a hypertrophic benefit to training at longer- rather than shorter-muscle lengths. Additionally, it appears that the inclusion of shorter-muscle length training by the full ROM condition did not enhance muscle hypertrophy compared to exclusively using LPs.”
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 design isolates the variable of muscle length by comparing full ROM (with short + long) to LPs (only long). The null result supports the claim without overstatement, using 'does not enhance' appropriately.
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.
Randomized Controlled TrialLevel 1bIn EvidenceWhether training only at long muscle lengths produces equal hypertrophy to full ROM when volume and stretch are matched, and short-length training is excluded.
Whether training only at long muscle lengths produces equal hypertrophy to full ROM when volume and stretch are matched, and short-length training is excluded.
What This Would Prove
Whether training only at long muscle lengths produces equal hypertrophy to full ROM when volume and stretch are matched, and short-length training is excluded.
Ideal Study Design
A within-participant RCT with 40 trained individuals comparing three conditions: full ROM, lengthened partials (long only), and shortened partials (short only), all matched for volume, intensity, and stretch pause, measuring muscle thickness at 45% and 55% humeral length.
Limitation: Limited to elbow flexors/extensors; cannot generalize to muscles with different fiber arrangements.
Systematic Review & Meta-AnalysisLevel 1aWhether excluding short-range training reduces hypertrophy compared to full ROM across multiple studies.
Whether excluding short-range training reduces hypertrophy compared to full ROM across multiple studies.
What This Would Prove
Whether excluding short-range training reduces hypertrophy compared to full ROM across multiple studies.
Ideal Study Design
A meta-analysis of 10+ RCTs comparing full ROM vs. partial ROM training at long muscle lengths, excluding studies using shortened partials, with standardized ultrasound measurements of muscle thickness in trained populations.
Limitation: Cannot control for differences in training history or exercise selection across studies.
Evidence from Studies
Supporting (1)
The study found that lifting weights through just the stretched part of the movement (like the bottom of a bicep curl) builds muscle just as well as lifting through the full motion — meaning you don’t need to fully contract the muscle to get big.