Is full range of motion better than partial reps?

On average, yes — but the difference is smaller than most people think. Meta-analyses show a minimal advantage for full ROM (effect size 0.13), which is statistically trivial to small. What matters most isn't full vs. partial, but where in the range you're training: the lengthened position (bottom of the movement) counts the most.

What are lengthened partials?

Partial reps performed only in the lengthened portion of the movement — for example, only the bottom half of a biceps curl or the bottom half of a squat. Current studies show these produce just as much muscle growth as full ROM.

When do partial reps actually make sense?

When you're dealing with pain or injury at specific joint angles, when advanced lifters are targeting a sticking point, or as a progressive ROM strategy — you start with the pain-free range and gradually work deeper over weeks.

Full ROM vs. Partial Reps: Which Builds More Muscle?

“Go deep” on squats. “Full range” on bench press. “All the way down” on curls. The instruction is clear: full range of motion is non-negotiable; anything less is cheating.

But is that actually true? And what about the new research on lengthened partials that’s been making the rounds?

What Range of Motion Actually Means

Range of motion (ROM) describes the movement arc of an exercise — from the fully lengthened to the fully shortened position of the target muscle.

Full ROM means moving through the entire range the joint and exercise allow. Deep squat to the bottom, bench press until the bar touches your chest, biceps curl from fully extended to fully contracted.

Partial ROM means you only move through part of that range — the top half, the bottom half, or the region around a sticking point.

What the Research Says: Full ROM Wins — Barely

A meta-analysis by Wolf et al. (2023) summarized the available studies. The finding: full ROM produces slightly more muscle growth than partial ROM — but the difference is small. The effect size is 0.13. That’s statistically “trivial to small.”

For strength, the picture is clearer: full ROM builds strength across the entire movement arc. Partial ROM primarily makes you stronger in the range you train, with a small carryover of roughly 15–20 degrees to adjacent joint angles. Someone who only does half squats won’t get meaningfully stronger in the deep position.

The ACSM 2026 Position Stand (Currier et al.) recommends full ROM as the standard — for strength, hypertrophy, and joint health.

Bonus: Strength training through a full range of motion improves flexibility comparably to stretching. Training with full ROM is essentially free mobility work.

The New Nuance: Not All Partial Reps Are Equal

This is where things get interesting — and where the research has moved in the last two years.

Partial reps are not all the same. What matters is which half you’re training:

Shortened partials (top half, contracted position): You move only through the upper portion of the exercise — for example, only the top half of a biceps curl or only the top half of a squat. This variant consistently underperforms full ROM in the research. Less muscle growth, less strength gain.

Lengthened partials (bottom half, lengthened position): You train only in the lengthened portion of the exercise — for example, only the bottom half of a biceps curl (arm nearly straight to mid-range) or deep squats to just above parallel. This variant produces just as much muscle growth as full ROM in current studies — and in some cases slightly more.

A well-controlled 2025 study (PeerJ) confirmed this in trained individuals: lengthened partials and full ROM produced comparable muscle growth in the arms and thighs.

Why? In the lengthened position, the muscle is under the highest mechanical tension — and mechanical tension is the primary driver of muscle growth. The stretched position is the part of the movement that matters most.

What This Means in Practice

The research refines the old “always go full ROM” rule — but it doesn’t overturn it. Here’s the practical picture:

Full ROM remains the default. Not because partial reps are useless, but because full ROM automatically covers the lengthened range — plus everything else. You build strength across the full arc, you improve your mobility, and you don’t have to think about which half you’re training. Full ROM is the safest default.

Lengthened partials are a legitimate alternative when:

Full ROM causes pain at a specific point — you can skip the problematic range and still train effectively
You want to squeeze in a few extra reps for a muscle at the end of a session without fully loading the joints
You want to deliberately emphasize the lengthened position of an exercise (e.g., preacher curls in the bottom half)

Shortened partials (top half) are rarely worth it. Exceptions: lockout training for powerlifters, or when injury rules out certain joint angles.

When Partial Reps Actually Help

Beyond the lengthened partials debate, there are three classic situations where restricted ROM makes sense:

After injuries. When full ROM in the knee, shoulder, or back is painful, partial reps let you keep training — in the range that’s pain-free. Physical therapists use this routinely: half squats as the starting point, going a little deeper each week.

Sticking-point training. Advanced lifters who fail at a specific point in the range (e.g., the very bottom of bench press) can work that exact position with heavier loads. A niche tool, but an effective one.

Progressive ROM expansion. If you don’t yet have the mobility for deep squats, you start with the range you can hit cleanly — and work your way deeper over weeks. Partial reps as a stepping stone, not a permanent solution.

The Short Version

Full ROM is the default. It automatically covers the growth-relevant lengthened range, builds strength evenly, and improves your mobility as a side effect.
Lengthened partials (bottom half) are equivalent for hypertrophy — a useful option, not an upgrade.
Shortened partials (top half) are inferior and only make sense in specific situations.
Partial reps have their place — after injuries, as a bridge to full ROM, or as a sticking-point tool.
The lengthened position counts the most. Whether you’re doing full or partial reps: make sure your muscle is working in the stretched position.

Further reading:

Sources

Wolf M, Androulakis-Korakakis P, Fisher JP et al. (2023). Partial Vs Full Range of Motion Resistance Training: A Systematic Review and Meta-Analysis. International Journal of Strength and Conditioning, 3(1).
Schoenfeld BJ, Vigotsky AD, Grgic J et al. (2024). Optimizing Resistance Training Technique to Maximize Muscle Hypertrophy: A Narrative Review. Journal of Functional Morphology and Kinesiology, 9(1):9.
Kassiano W, Costa B, Kunevaliki G et al. (2023). Greater Gastrocnemius Muscle Hypertrophy After Partial Range of Motion Training Performed at Long Muscle Lengths. Journal of Strength and Conditioning Research, 37(9):1746–1753.
Nóbrega SR, Scarpelli MC, Barcelos C et al. (2025). Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals. PeerJ, 13:e18904.
Currier BS, D’Souza AC, Singh MAF et al. (2026). Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews. Med Sci Sports Exerc. 58(4):851–872.

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