Get Pumped with Partial Reps

by on September 27, 2017

A recent study shows that training through a partial range of motion led to almost twice as much muscle growth as full ROM training.

Do you require a half gallon of Lakota cream on your aching knees before a set of squats?

Do you need to jump in an ice bath after every set of presses?

There just comes a time in a lifter’s life where you may have to make provisions to your training for safety and longevity.

But this doesn’t mean you must retire your weight belt and take up an aquafit class.

Train smarter, not harder.

When most think of progress, they think of continuously adding weight to the bar week after week.

But there are many ways to go about it.

The progressive overload principle basically states: In order for a muscle to grow, strength to be gained, performance to increase, or for any similar improvement to occur, the human body must be forced to adapt to a tension that is above and beyond what it has previously experienced.

One way to progress without adding weight to the bar, which has long been used by bodybuilders, now has a study to back its effectiveness – partial reps.

Partial Reps Explained

As a follower of John Meadows, you know extending the set with partial reps is an effective training tool.

See the strategy in action here:

Beyond the reduced joint stress, why partial reps?

You can go beyond failure and increase time under tension (i.e. get yoked!) without going for max lifts.

Basically, when you get to a point where you can no longer perform a rep fully with good form, just involve the bottom portion of a rep (1/4-1/2 reps) to extend the set and push past failure.

There’s some scientific backing now, with a recent study showing a partial range of motion led to almost twice as much muscle growth as full ROM training.

The New Study Results

The recent study can be found here in its entirely.

It put 44 young men with at least one year of training experience, who regularly trained their triceps at least once per week, to the test.

Split into a full-ROM and partial-ROM group, they each did barbell triceps extensions three times per week for eight weeks, performing 3 sets of 8 reps per session with a minute between sets.

The key findings, first reported by Greg Nuckols in his MASS research guide, found the partial-ROM triceps extensions group had nearly twice as much hypertrophy as the full-ROM group.

What’s Happening Here?

John Meadows has been preaching constant tension for years when hypertrophy is the goal, which generally involves stopping a movement just short of full ROM and not locking out each rep.

Previous research supports that lifting with continuous tension can provide a potent stimulus for muscular hypertrophy, even when relatively light loads are used (Tanimoto et al., 2008).

But most studies on partial reps before this one compared a full ROM to the top half of a ROM – deep squats versus half squats, for example – in contrast, a constant tension approach to squatting is more about emphasizing the eccentric/bottom half of the movement, prolonging muscle tension.

This study compared full-ROM training to partial-ROM training the way it’s typically used for hypertrophy, employing an approach that keeps constant tension on the muscle in a stretched position. I.E. Emphasizing the eccentric lowering of the weight and staying in that groove.

Still A Time & Place For Partials

When performing the big basic lifts such as squats, deadlifts, and barbell bench presses, focus on lifting big weights and using good form, not trying to push beyond failure with partials out of the hole. That’s asking for trouble.

However, for more targeted isolation movements, this approach is very effective. Think of a piston continuously moving up and down with no built-in rest periods – that’s what you want your reps to look like.

Partial-ROM “constant tension” training is useful for exercises where it’s difficult to keep tension on the target muscle through the full range of motion, such as barbell triceps extensions or pec flyes.

It also plays a part, as John illustrates, in extending sets on exercises that allow you to do it safely and effectively (think dumbbell or machine exercises).

Some Reasons To Be Skeptical

As the MASS review outlines, there are two reasons to be somewhat sceptical:

The increases in both groups were substantial. Even the full-ROM group averaged a 28.2% increase in triceps hypertrophy (measured as triceps cross-sectional area), but that pales in comparison to the 48.7% mean increase in the partial-ROM group.

That would be impressive enough in untrained lifters, but these folks had at least one year of training experience.

The unexpectedly large increases in triceps size may be attributable to some factor that wasn’t accounted for, such as an increase in muscle glycogen storage.  If that was the case, you would probably expect to see larger increases in the partial-ROM group since the acute stress (and thus the stimulus to increase glycogen storage) was larger.

And two, the authors estimated triceps hypertrophy through the cross-sectional area. A better reference point would’ve been actual muscle thickness. However, if this was a source of error, you’d expect it to skew both groups equally instead of providing a proportional advantage to one group.

There’s another potential explanation for the hypertrophy observed in the partial-ROM group that the authors didn’t discuss, according to Nuckols.

Rep speed was standardized so that each eccentric and each concentric took one second in both groups.  However, the full-ROM group covered a greater ROM each second, whereas the partial-ROM group covered a portion of ROM in the same length of time, increasing time under tension.  As such, it’s likely that the partial-ROM group was training with heavier relative loads on the muscle and working close to failure.

Nonetheless, the nearly two-fold larger increase in estimated triceps size for the partial-ROM group really warrants the inclusion of this training method in your program.

Take Home Points

  1. If training for muscle gains first and foremost (you are on MD’s site after all), training through the middle of the ROM instead of a full ROM may allow for greater gains
  2. Save this style of training for accessory exercises and/or to extend sets beyond failure.


Mitch Calvert is a certified trainer and fat-loss coach. He discovered his love for fitness while slaving away as a 240lb line cook 13 years ago – and now works specifically with men like his former self who have weight to lose and confidence to gain. Get Mitch’s handy “Mansformation Cheat Sheet” to simplify your diet.