Pressing depth is the deciding factor in the lengthened partials vs full ROM debate.
Key Takeaways of Lengthened Partials vs Full ROM
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Lengthened partials vs full ROM (Range of Motion) produced similar chest-growth results in this study.
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Researchers found no significant differences at any of the seven ultrasound measurement sites.
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Maximal strength gains were also similar.
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The small sample makes it difficult to detect modest differences.
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For most lifters, using a controlled full range of motion remains the safer default.
Why This Debate Matters
Range of motion changes the muscle length and joint position used during an exercise. Some researchers have proposed that training at longer muscle lengths may create a strong stimulus for hypertrophy, or muscle growth, because the target muscle remains under tension while stretched (Akagi et al., 2020).
However, that does not mean every lengthened partial exercise will outperform a complete repetition. The result may depend on the muscle, exercise, resistance profile, and portion of the movement removed.
That is why the question of range of motion for chest growth needs to be tested with chest-specific exercises rather than borrowed from studies on the quadriceps or elbow muscles.
What Does the Lengthened Partials vs Full ROM Study Examine?
In a 2026 book chapter published in Lecture Notes in Bioengineering, Oo and colleagues examined lengthened partials vs full ROM during Smith-machine bench pressing (Oo et al., 2026).
The study included 11 untrained men. Each participant trained one side of the chest with full-ROM pressing and the other side with lengthened partial repetitions through the bottom half of the movement. The intervention lasted eight weeks.
Researchers measured chest-muscle thickness at seven ultrasound sites. They also assessed maximal voluntary contraction, or MVC, and one-repetition maximum, or 1RM, strength.
Because each participant trained under both conditions, the design allowed researchers to compare the two methods within the same person. Still, the small sample limited the study’s ability to detect modest differences.
How Lengthened Partials vs Full ROM Affects Chest Hypertrophy
Chest hypertrophy
The researchers found no significant difference in chest-muscle growth between full-ROM and lengthened-partial training at any of the seven ultrasound sites (Oo et al., 2026).
That finding does not mean both methods produced exactly the same amount of growth. It means the study did not detect a statistically significant difference between them.
Strength
MVC and 1RM strength gains also did not differ significantly between conditions (Oo et al., 2026).
These results require additional caution. Strength gains from training one side can transfer to the opposite side through neural adaptations, a phenomenon known as the cross-education effect (Bell et al., 2023). That transfer could have reduced the apparent difference between the two pressing conditions.
What Earlier Research Says About Lengthened Partials vs Full ROM for Hypertrophy
The findings are broadly consistent with Wolf and colleagues’ 2025 study. They recruited 30 resistance-trained participants, although 25 completed the eight-week intervention and were included in the final analysis (Wolf et al., 2025).
The researchers compared lengthened partial and full-ROM upper-body training. They measured the elbow flexors and elbow extensors, not the chest. They reported similar changes in muscle thickness and unilateral lat-pulldown 10RM performance between conditions (Wolf et al., 2025).
Therefore, Wolf et al. provide relevant but indirect context. Their results do not directly confirm what happens during chest training, because the participants, exercises, and measured muscles differed from those in the Oo study.
Other research also suggests that range-of-motion outcomes can vary by exercise and muscle. Bloomquist and colleagues reported different muscle and tendon adaptations after squat training with different movement depths (Bloomquist et al., 2013). Akagi and colleagues also examined how training at different muscle-tendon unit lengths influenced muscle and neuromuscular outcomes (Akagi et al., 2020).
These studies support a cautious conclusion: lengthened partials for hypertrophy may not have one universal effect across all exercises.
What Should You Do in the Gym?
A controlled full-ROM bench press remains a sensible foundation for chest training. It gives you a consistent movement standard and exposes the target muscles to a broader range of joint positions.
Before replacing full-ROM pressing with partial repetitions, check whether your current technique uses enough depth. Many lifters shorten the bottom portion of dumbbell and barbell presses to move more weight. That is a technique problem, not evidence that lengthened partials are superior.
You can still use lengthened partials as an optional variation. For example, they may help you add focused work in a specific portion of an exercise. However, the current chest-specific evidence does not justify replacing full-ROM pressing with bottom-half repetitions.
Limitations
The Oo study had several important limitations:
- It included only 11 untrained men.
- The intervention lasted only eight weeks.
- The findings may not apply to trained lifters, women, older adults, or other pressing variations.
- The study’s strength outcomes may have been influenced by cross-education between sides.
- The absence of a significant difference does not establish that the methods are equivalent.
Conclusion
This chest-specific study found no significant difference between lengthened partials vs full ROM for chest thickness or strength after eight weeks (Oo et al., 2026).
The result aligns with a separate study that found similar upper-body adaptations in trained participants, although that research did not measure chest hypertrophy (Wolf et al., 2025). For now, use a controlled full-ROM bench press as your default. Treat lengthened partials as an optional tool, not a proven upgrade.
Are lengthened partials better than full-ROM bench presses?
Lengthened partials vs full ROM produced no significant difference in chest growth or strength in the Oo study (Oo et al., 2026). However, the study was small and short, so it cannot rule out modest differences or establish that both methods work identically for all lifters.
Did the new study prove that full ROM and partials are equivalent?
No. Lengthened partials vs full ROM showed no statistically significant difference, but that does not prove equivalence. A larger study would provide a stronger test of whether one method produces a small but meaningful advantage.
Did Wolf et al. study chest hypertrophy?
No. Lengthened partials for hypertrophy were studied in trained participants, but the researchers measured the elbow flexors and elbow extensors rather than the chest (Wolf et al., 2025). The study is useful context, not direct evidence about chest growth.
Is a full-ROM bench press still useful for chest growth?
Yes. Full ROM bench press training remains a practical default because it provides a consistent progression standard and trains the movement through a broader range. The new study did not show that full ROM was superior, but it also did not show that partials were better.
What is the best range of motion for chest growth?
Range of motion for chest growth should be large enough to train the target muscles through a controlled, comfortable movement. Your technique, shoulder position, loading, and ability to progress also matter. The current evidence does not identify one universal range that is best for every lifter.
Medical Disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice. Consult a qualified healthcare provider before making changes to your diet, supplementation, or training program.
References
Akagi, R., Hinks, A., & Power, G. A. (2020). Differential changes in muscle architecture and neuromuscular fatigability induced by isometric resistance training at short and long muscle-tendon unit lengths. Journal of Applied Physiology, 129(1), 173–184. https://doi.org/10.1152/japplphysiol.00280.2020
Bell, Z. W., Wong, V., Spitz, R. W., Yamada, Y., Song, J. S., Kataoka, R., Chatakondi, R. N., Abe, T., & Loenneke, J. P. (2023). Unilateral high-load resistance training influences strength changes in the contralateral arm undergoing low-load training. Journal of Science and Medicine in Sport, 26(8), 440–445. https://doi.org/10.1016/j.jsams.2023.06.011
Bloomquist, K., Langberg, H., Karlsen, S., Madsgaard, S., Boesen, M., & Raastad, T. (2013). Effect of range of motion in heavy load squatting on muscle and tendon adaptations. European Journal of Applied Physiology, 113(8), 2133–2142. https://doi.org/10.1007/s00421-013-2642-7
Oo, K., Lukic, G. W., Keen, K. T., Zhen, L. Y., & Yusof, A. (2026). The effects of full range of motion and lengthened partial range of motion on chest hypertrophy and strength. In Lecture Notes in Bioengineering (pp. 571–593). Springer Nature Singapore. https://doi.org/10.1007/978-981-95-9653-9_53
Wolf, M., Androulakis Korakakis, P., Piñero, A., Mohan, A. E., Hermann, T., Augustin, F., Sapuppo, M., Lin, B., Coleman, M., Burke, R., Nippard, J., Swinton, P. A., & Schoenfeld, B. J. (2025). Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals. PeerJ, 13, e18904. https://doi.org/10.7717/peerj.18904
About the Author
Robbie Durand
Robbie Durand is an exercise physiologist and science writer specializing in evidence-based fitness and nutrition research. With over 15 years of experience translating peer-reviewed studies into actionable advice, Robbie helps readers make informed decisions about training, supplementation, and body composition.
