One of the rules of building a symmetrical and balanced body is making sure you complete every rep using a full Range Of Motion (ROM). What that means is you should get a full stretch at the bottom of the movement, then make sure you’re fully contracting and squeezing the muscle at the top of the movement.

Working your muscles through a full range of motion challenges them over a greater length, especially in the stretched position, which is now recognized as a key driver of muscle growth.

However, some trainers and fitness authors have stated that partial reps are an effective way to increase muscle mass. (A partial rep is part of a complete repetition where the muscle works in a shortened range of motion. You can start a partial at the top or bottom of a repetition, then move as little as 1/4 to as much as 3/4 of the way through a full range of motion.)

Who’s right? We decided to look at the research.

Multiple studies and meta-analyses conducted between 2020 and 2025 have examined this question using much larger sample sizes than earlier research. The current evidence is clearer than it was two decades ago when we first wrote this article.

Recent systematic reviews consistently show that full-range-of-motion training produces superior results for muscle growth and strength development in most people. A 2020 meta-analysis in Sports Medicine found that full ROM typically leads to greater increases in muscle size compared to partial range training.

However, the story isn’t completely one-sided. Studies from 2022-2023 have revealed something interesting: partial reps performed in the lengthened position (like the bottom half of a bicep curl or squat) can match or occasionally exceed full ROM for muscle growth, though the difference is small. The key factor appears to be training the muscle when it’s stretched, not necessarily completing the entire range of motion.

Meanwhile, partial reps performed only in the shortened position (like the top half of movements) are consistently less effective for muscle growth than full ROM training.

What this means for your training.

Current research strongly supports full range of motion as the foundation of your training program. The differences aren’t huge, but they’re consistent enough to matter over time.
BUT partial reps can still be useful in specific situations:

For advanced lifters: Combining full ROM with lengthened partial reps may enhance muscle growth slightly beyond full ROM alone, especially if you’ve been training consistently for several years.

For strength at specific angles: Partial reps can help you overcome sticking points in lifts by strengthening you at those specific joint angles.

For adding variety: Partial reps can break training monotony and provide a different stimulus when progress stalls.

Partial reps work best as a supplement to full-range-of-motion training, not a replacement.

Here are safe ways to use them:

Stick to lengthened partials when possible. Focus on the stretched portion of movements rather than the shortened range. For example, do the bottom half of a squat or bicep curl rather than just the top portion.

Use them as finishers. For most people, you should limit partial reps to the last set or two of an exercise. Use them to finish off an already fatigued muscle group.

Don’t exceed your actual strength. Avoid the temptation to use weights that are too heavy for you to control properly through any range of motion. This can lead to poor form and increase the risk of injury.

Rotate them periodically. While there’s no magic timeframe, using partial reps for a few weeks then returning to full ROM can help prevent staleness and overuse patterns.

Important Safety Considerations

If you have an injury: Never self-prescribe partial rep training for injuries. Range of motion restrictions due to injury should only be managed under guidance from a physical therapist or qualified medical professional. Inappropriate training around injuries can worsen problems or create new ones.

Recovery needs vary: Partial reps performed in lengthened positions can actually increase muscle damage and recovery time compared to some full ROM training. Don’t assume they’re always easier on your body.

Form still matters: Partial reps aren’t an excuse for sloppy technique. Maintain strict control throughout whatever range of motion you’re using.

Full range of motion should be the foundation of your training program. Current research consistently shows it produces the best results for most people and most goals.

Partial reps have their place as a supplemental tool, particularly lengthened partials for advanced lifters looking to add variety or target specific weaknesses. However, they work best when used strategically alongside full ROM training, rather than as a replacement for it.

If you’re just starting or have been training for less than a couple of years, stick with full-range-of-motion movements. Master the basics first, then consider adding partial reps as an advanced technique when your progress naturally slows down.

Remember, the best training program is one you can follow consistently while staying injury-free. Full range of motion gives you the best foundation for both.

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Reference Links:

Partial Vs Full Range of Motion Resistance Training: A Systematic Review and Meta-Analysis

Milo Wolf, James Fisher, Brad Schoenfeld, James Steele
International Journal of Strength and Conditioning, Published 2023-03-02

Click Here for the Study: https://doi.org/10.47206/ijsc.v3i1.182

 

Greater Gastrocnemius Muscle Hypertrophy After Partial Range of Motion Training Performed at Long Muscle Lengths

Kassiano, Witalo; Costa, Bruna; Kunevaliki, Gabriel; Soares, Danrlei; Zacarias, Gabriel; Manske, Ingrid; Takaki, Yudi; Ruggiero, Maria Fernanda; Stavinski, Natã; Francsuel, Jarlisson; Tricoli, Ian; Carneiro, Marcelo A. S.; Cyrino, Edilson S.
The Journal of Strength and Conditioning Research, Published September 2023. | DOI: 10.1519/JSC.0000000000004460

Click Here for the Study: https://journals.lww.com/nsca-jscr/fulltext/2023/09000/greater_gastrocnemius_muscle_hypertrophy_after.3.aspx

 

Effects of range of motion on muscle development during resistance training interventions: A systematic review

Brad J Schoenfeld and Jozo Grgic
Safe Journals SAGE Open Medicine, Published online January 21, 2020

Click Here for the Study: https://doi.org/10.1177/2050312120901559

 

Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals

Milo Wolf, Patroklos Androulakis Korakakis​, Alec Piñero, Adam E. Mohan, Tom Hermann, Francesca Augustin, Max Sapuppo, Brian Lin, Max Coleman, Ryan Burke, Jeff Nippard, Paul A. Swinton, Brad J. Schoenfeld
Sports Medicine and Rehabilitation, Published February 12, 2025

Click Here for the Study: https://peerj.com/articles/18904/

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12/10/2006
Updated 12/21/2012
Updated 9/4/2025