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

A half rep can be worse, just as good, or in a particular context even more useful than a full rep.

That sounds contradictory until you stop distinguishing only between “full” and “half”.

Because with partial reps, what matters is which part of the movement gets trained.

This is exactly where the research has moved on in recent years. The old rule that “full ROM is always superior” is too crude. But the new rule that “lengthened partials are better than full ROM” is equally premature.

What range of motion actually means

Range of motion (ROM) describes the movement range of an exercise, or of a joint.

On a squat, a larger ROM can mean more knee and hip flexion, for instance. On a curl it describes the path between a more extended and a more flexed elbow.

Full ROM does not necessarily mean training a muscle from anatomically maximal stretch to maximal shortening. Exercises, machines, grip positions and joint anatomy set different limits.

For practical purposes, a simpler definition is enough:

Full ROM = the complete controlled movement path you have set for that exercise.

Partial ROM = only a defined part of that path.

That can be the top half, the bottom half or a very small angular range.

What the meta-analysis says: full ROM only wins narrowly overall

The systematic review and meta-analysis by Wolf et al. (2023) pooled studies on full and partial ROM across different training goals.

The overall result:

Full ROM showed a trivial advantage of roughly SMD 0.12.

The effect sizes for individual outcomes were likewise mostly in the trivial to small range.

That is an important correction to two extremes:

• Partial reps are not useless in principle.
• But full ROM remains a very robust default, because it trains large parts of the available movement range and develops strength across that range.

For strength in particular, the principle of specificity also applies: you get stronger above all in the joint angles you train, with some carry-over into neighbouring ranges.

So anyone training only the top portion of a squat should not expect deep squats to get stronger to the same degree.

Not every partial rep is the same

The most interesting part of the current discussion is muscle position.

Simplified, you can think of partial reps in two directions.

Shortened partials

You mainly train the range in which the target muscle is relatively shortened.

On a curl, for example:

only the top portion, towards maximal elbow flexion.

Lengthened partials

You mainly train the range in which the target muscle is relatively long.

On a curl, for example:

from the nearly extended arm to roughly the middle of the movement.

It is these lengthened partials that have drawn a lot of attention in recent years.

What we know about training at long muscle lengths

Several studies suggest that resistance training at longer muscle lengths can be particularly productive for hypertrophy.

That applies not only to classic partial-rep studies but also to comparisons of exercise angles and muscle positions.

In the calf, for example, Kassiano et al. (2023) showed greater hypertrophy from partial reps in the more stretched range than from a different ROM protocol.

It is important not to oversimplify the mechanism, though.

The claim:

In the stretched position, mechanical tension is always highest.

is not generally correct in that form. An exercise’s external resistance curve can have its hardest point somewhere else entirely.

The better statement is:

Training at long muscle lengths appears to be a relevant hypertrophy factor in itself — but why, and to what extent, depends on the muscle and the exercise.

The 2025 study on lengthened partials

A particularly relevant study by Wolf et al. (2025) compared, in 30 trained individuals over eight weeks:

• full ROM
• lengthened partials

The conditions were assigned to different limbs within the same person.

The result: the changes in the upper-body musculature examined were very similar, with data that argued moderately for no relevant difference between the conditions.

That is a strong argument for taking lengthened partials seriously.

But it is not proof of:

Lengthened partials are just as good as or better than full ROM for every muscle.

The study ran eight weeks, examined a limited selection of exercises and muscle measurements, and is one part of a still young literature.

So the practical conclusion should be more conservative:

Lengthened partials are a legitimate hypertrophy option. Full ROM remains the simpler default with a broader evidence base.

Why full ROM still makes a very good default

Full ROM solves several problems at once.

You train strength across a larger range

Partial strength is specific.

If you need a larger range of motion in daily life, in sport or in another exercise variation, it makes sense to train that range under load regularly too.

A large ROM automatically trains longer muscle lengths as well

You do not have to decide for every exercise exactly where the optimal partial range lies.

A sensibly performed full-ROM rep usually already contains the long-muscle range.

Strength training through a large ROM improves flexibility

Meta-analyses show that strength training through large ranges of motion can improve mobility — in some cases to a degree comparable with stretching.

Which gives you strength and a flexibility adaptation within the same exercise.

When lengthened partials are practically useful

1. Extra reps after full ROM

One interesting use is mechanically extending a set.

You do curls through a full ROM, say, until no further complete rep is possible cleanly. Then a few more reps follow in the longer-muscle range.

That increases the work in the set without immediately adding another exercise.

Whether it is better in the long run than simply doing another normal set is not conclusively settled. As a method, though, it is plausible and practical.

2. Exercises with a strong focus on long muscle lengths

Some exercises can be chosen or performed deliberately so that the target muscle is heavily loaded through a long range.

Partial ROM there can then serve as a training stimulus of its own.

3. When full ROM is not currently tolerated

A limited range of motion can be useful in training and rehabilitation when a larger ROM currently provokes complaints.

Important: pain is not a simple technique problem. Anyone with relevant or persistent complaints should not work out which joint angle is “safe” from an internet article.

The sensible idea is more like:

Train the range you tolerate well and widen it gradually where needed.

When other partial reps can make sense

Not every partial rep has to be aimed at muscle growth.

Sticking-point training

Strength athletes can train specific sections of a competition lift deliberately.

Pin squats, board presses or certain rack pull variations are examples.

The benefit here comes from specificity in the relevant angular range, not from a general hypertrophy advantage.

Overloading a particular section of the movement

In a stronger part of the movement, you can sometimes use larger external loads than across a full ROM.

That can make sense in specialised phases, but it changes the training stimulus considerably.

Progressive ROM

You can also widen a range of motion systematically.

For example:

• start with a controlled squat to a depth you tolerate well
• allow more depth over the weeks
• raise the load only as far as control is maintained

That is not “cheating” but a form of progression.

Shortened partials: really always worse?

The current literature argues more strongly for training at long muscle lengths than for exclusively shortened positions.

Even so, “shortened partials are always inferior” would be too absolute.

They can, for instance:

• train sport-specific angles
• overload a particular strength range
• be chosen for technical or therapeutic reasons

For general muscle growth there is simply less reason to favour the shortened range exclusively when a larger or length-emphasised ROM can be trained well.

Which is a different statement from “top half reps do nothing”.

What this means for squats

With squats, ROM often gets confused with “ATG or not?”.

The sensible depth is individual and depends on the goal.

Deeper squats change joint angles, muscular demands and the strength curve being trained. For hypertrophy and strength across large ranges of motion, there is a lot in favour of using as much controlled and well-tolerated depth as possible.

That does not mean every person needs the same visual end position, though.

How anthropometry, stance and bar position change the movement is covered in squat technique: individual, not dogmatic.

And why “knees over toes” is not automatically dangerous in that is covered in the Knees Over Toes / ATG check.

The short version

• Full ROM remains a very good default. It trains strength across a large range and usually includes long muscle lengths automatically.
• The differences between full and partial ROM are smaller in meta-analyses than many rules suggest.
• Lengthened partials are promising. A 2025 study in trained lifters found similar muscular adaptations to full ROM.
• It does not yet follow that lengthened partials are equivalent or superior for every muscle.
• Training at long muscle lengths appears relevant for hypertrophy; that is not the same as “mechanical tension is always highest there”.
• Partial ROM can also be useful for sticking points, sport specificity or progressively widening your ROM.
• The best range of motion is not the largest at any price, but the largest you can train in a way that is controlled, purposeful and well tolerated.

Further reading:

• Mobility through strength training
• Squat technique: individual, not dogmatic
• Knees Over Toes: the ATG science check

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.
• Wolf M, Androulakis-Korakakis P, Piñero A 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.
• Afonso J et al. (2021). Strength Training versus Stretching for Improving Range of Motion: A Systematic Review and Meta-Analysis. Healthcare, 9(4):427.
• 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. Medicine & Science in Sports & Exercise, 58(4):851–872.