The Study
Partial Range, Full Gains? The Effect of 8 Weeks of Partial Range of Motion Training at Long Muscle Lengths on Elbow Flexor Hypertrophy and Strength in Trained Individuals
This study shows that if you train your biceps with a short arm movement vs. a full one, you might get a tiny bit more muscle growth in one spot — but it’s not a big difference. It doesn’t prove one way is better for everyone, just for these 13 people.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
People who already lift weights did arm curls with either a short motion (halfway) or full motion for 8 weeks to see which builds more muscle and strength.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 565 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The differences are tiny—so small that most people wouldn’t notice them in real life.
- 2Both methods work well overall.
- 3Half-motion curls built slightly more muscle near the wrist (0.10x bigger effect).
- 4Full-motion curls built slightly more total strength (0.17x bigger effect).
- 5Both built similar muscle near the shoulder.
- 6Strength at 100° bend improved more with half-motion (0.24x bigger effect).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Sport Science
Year
2025
Authors
Tim Havers, Niklas Wagner, Steffen Held, Stephan Geisler, T. Wiewelhove
Related Content
Claims (10)
In trained individuals, lifting weights through partial ranges of motion or at longer muscle lengths produces the same amount of muscle growth as lifting through full ranges of motion.
For people who are already trained, lifting weights with muscles stretched out does not result in more muscle growth than lifting with muscles shortened, and it does not result in less muscle growth than lifting through a full range of motion.
When trained people lift weights using either a partial range of motion at long muscle lengths or a full range of motion, and both methods use the same total workload and effort, the amount of muscle growth is the same.
Doing only the bottom part of an exercise (where the muscle is stretched) can build as much muscle in your arms and legs as doing the full movement, as long as you put in the same amount of effort and work.
When people who regularly lift weights perform exercises that stretch their muscles fully, they gain more strength in movements that involve those stretched positions, such as bending the elbow while the muscle is lengthened.
Resistance training with muscles stretched further may lead to different muscle growth outcomes in people who are new to training versus those who are experienced, but there is not enough reliable data yet to know for sure.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.