HOW DOES RANGE OF MOTION AFFECT GAINS... Can you get the same gains from partial lifts as full R.O.M?

Simply put, range of motion refers to the distance & direction a joint can move under muscle tension. Training with a full R.O.M implies you go through the full movement potential for a given exercise. Training with a partial R.O.M indicates compromising the R.O.M, falling short of max range.

Most people tend to fall into one of two camps: the Science Camp or the Bro Camp. People in the Science Camp generally argue that a full R.O.M is better for muscle growth & partial reps are just ego reps. Some of you likely find yourselves agreeing more with the Bro Camp & prefer the use of partial reps for one of these reasons:

1.     They allow you to move more weight.

2.     They permit you to keep constant tension on the muscle by keeping the weight in the mid-range.

3.     Many pro bodybuilders use partials & they’ve achieved better gains than all of us.

Both sides have some valid points. but let's start by looking at the partial R.O.M camp.

1.     Partials allow you to move more weight, with more tension on the muscle.

Although you’ll be able to load more weight on when you cut the R.O.M short, this doesn’t mean you’re putting more tension on the muscle. The extra weight is coming at a cost; as you increase the weight, you’re simultaneously decreasing the distance that weight is moving resulting in a net less tension on the muscle. Therefore, from a hypertrophic standpoint, that increase in weight simply isn’t worth the trade-off in distance.

2. Partials can allow you to maintain constant muscle tension.

This second argument for partial R.O.M is much stronger (even though it sounds nearly identical to the previous argument). Rather than just cutting the range of motion in half (e.g. lowering the bar only halfway to your chest during a bench press), the constant tension advocates tend to stop just shy of full lockout by cutting out the top & bottom of each rep. Their idea here is that if you fully lock out a rep, your muscle gets a mini rest & briefly loses tension in between reps.A 2017 study supports this, where researchers compared doing skull crushers through a full range of motion to doing skull crushers through a half range of motion (the middle part of the lift). After eight weeks working with experienced lifters, they found significantly better muscle growth in the partial group (nearly twice the gains).

Before we get too excited about this study, I should point out that of the six studies I found on R.O.M, this is the only one that favoured using a partial range of motion. Probably because the skull crusher as an exercise involves low tension at the bottom & top of the movement, whereas most lifts don’t.

3. Bodybuilders use partials.

Bodybuilders do use partials, but it’s hard to say if these bodybuilders are getting their results from partials specifically, or from some other training variables, great genetics, nutrition etc. This deosn’t mean to say partials aren’t working for some people such as bodybuilders, just that there is little evidence yet, so we have to go with what we know for certain.

What the science says for certain...

We aren’t going to go through all six studies I found, but the bottom line is that all four lower body studies found that a full range of motion was better, & the upper body studies gave mixed results. One upper body study found no difference between doing full range curls & partial curls, & the other was the skull crusher study we just discussed.

Overall, we have good enough evidence to say that a full range of motion is usually better for muscle growth.

Exceptions from the full R.O.M rule...

It does make sense to use partials as an advanced technique on some isolation exercises. For example, the bottom of dumbbell lateral raises, because there’s no tension on the delt down there. This allows an intentional build-up of time under tension to increase energy & time efficiency too.

That's all for this week, a sciencey one for you fellow geeks out there! Next week is a juicy one... we'll be discussing some of the morals behind obesity. See you there!

Elliot Hutchinson // 23.03.2025

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