It’s easy to scoff at people in the squat rack who load up their bar with five plates and bend their knees a few inches. From the bench press to biceps curls, those performing partial repetitions — whether intentionally or otherwise — are often labeled lazy or inattentive to their technique.
While this may be true in some cases, range of motion in training isn’t an open-and-shut case. In fact, if you roll your eyes every time you see someone cutting their sets short, the joke might be on you.
Partial repetitions have a place in the playbook of any competent gymgoer, whether they want to get a bit stronger or add a bit of muscle mass. However, it’s a thin line between worthwhile and wasteful. We’re going to break down the science and application of partial reps so you can walk it properly.
- What Are Partial Reps?
- Partial vs. Full Range of Motion
- Benefits of Partial Reps for Hypertrophy
- Benefits of Partial Reps for Strength
- What to Consider Before Using Partial Reps
What Are Partial Reps?
Partial reps are exactly what they sound like — any repetition of a given exercise performed by omitting a portion of the range of motion. The most common and obvious example being a “half squat”, where the trainee’s thighs don’t reach parallel to the floor.
Many partial reps are done by accident. If you’re new to lifting weights, it can be scary, uncomfortable, or both to sink low into a squat with a bar on your back. Mobility restrictions, poor sense of balance, or even ego can cause you to cut your reps short on any exercise.
However, when utilized properly and intentionally, partial reps can supplement a proper training program to increase muscle gains or boost strength.
Partial vs. Full Range of Motion
Unlike some other hotly-debated topics in training or nutrition, the jury is in about range of motion. For most people and most goals, utilizing a given joint’s full range of motion is optimal.
Systematic reviews of the literature on the subject tend to corroborate the idea that range of motion is an area where more actually is more, at least when it comes to hypertrophy. (1) For those pursuing inhuman levels of strength, the picture is a little less clear.
Most of the available literature confers the idea that strength adaptations are specific to the range of motion trained. (2) For competitive powerlifters, who have to squat to a specific depth at a meet, this confirms the importance of practicing the way they must perform.
However, partial range of motion training is also commonly used in powerlifting, weightlifting, or strongman programs as a means of shoring up weaknesses in areas of movement. As such, range of motion is only as useful as the context in which it is applied — which is what makes partial reps effective.
Benefits of Partial Reps for Hypertrophy
Pursuing a lean, muscular physique takes more than a good diet (although it can really, really help). To maximize muscle gain, bodybuilders need to have a wide arsenal of weaponry at their disposal. Partial reps fit right in alongside supersets or cluster training when it comes to cranking up workout intensity.
Mechanical tension is the primary factor driving hypertrophy. If there’s no physical stress placed on your biceps, they have no impetus to adapt and grow. As such, it only makes sense to zone in on where your muscle experiences the most pressure.
Research backs the idea that muscular tension is not consistent, especially when working with free weights. When your muscles fully lengthen or contract, mechanical tension is dampened as your tissues compress on each other for support. (3)
To that end, cutting out a bit of range of motion at the beginning or end of each rep could help get more stress where it’s meant to be, leading to greater growth over time.
More Metabolic Stress
Incurring a sufficient amount of metabolic stress in a muscle also catalyzes new growth. Put simply, performing physical work with a muscle necessitates that your body clear the waste products and deliver helpful nutrients to rebuild the tissue bigger and better. (4)
In a vacuum, more range of motion is more physical work than less. However, high-range-of-motion movements are not always well-suited to high rep training. Taller lifters commonly find themselves out of breath before they can do enough squats to really thrash their quads.
Partial reps pair nicely with intensity techniques like drop sets. It is far easier to strip plates for back-to-back working sets in the squat if you aren’t going ass to grass. By cutting the range of motion and amping up the work density, you can induce enough metabolic stress to make gains.
Benefits of Partial Reps for Strength
Partial reps are not exclusively the province of physique enthusiasts. In fact, they’re a common facet of most competitive strength programs. For those who make the barbell their sport, selective ranges of motion are a potent training tool.
The Olympic lifts are fluid and artful, but have many moving parts. The same holds true for the bench press and deadlift. Since competitive exercises are so intricate, there are many places where technique errors or power leaks could spell disaster for your performance.
Partial reps allow you to isolate the areas of a given lift that you’re weakest in. If you’re having trouble locking out your deadlifts, pulling from low blocks will let you overload the movement and get high-quality practice where you need it. Snatch deadlifts or pulls allow an athlete to refine their technique in the first half of the lift without worrying about catching the barbell.
Work Around Injury
There’s no reason to derail your progress by forfeiting yourself to the couch if you’re injured. Training through an injury requires a steady hand and careful attention to your body, but you can continue to make gains.
Some literature cites partial range of motion movements as a valid pathway in rehabilitation settings. (5) Since joint stressors can commonly be localized to a specific area, simply removing the portion of an exercise that causes pain may allow you to keep lifting without slowing your recovery.
What to Consider Before Using Partial Reps
There’s no single solution to making size or strength gains. Partial reps can be a valid aspect of your performance repertoire, but only if used properly. If thrown into a training plan haphazardly, you might be cutting more than your range of motion short.
Any training technique can sound alluring, and partial reps are no different. While there is support behind using them to great effect in certain contexts, take time to consider if they’re relevant to your needs in the first place.
If you’re just starting out in the gym and are only interested in gaining muscle, the deck is already stacked in your favor. Partials may be fun to experiment with, but keeping it simple with your training is probably best in your first few years.
Further, if you’ve started exercising to improve your flexibility, partial reps are functionally antithetical to that goal. Muscles are malleable, but only if you push them to new ranges under load. Cutting your squat depth will never help you squat deeper.
Partial reps are not equally effective with every piece of equipment. For hypertrophic purposes, one of the major selling points involves targeted tension — the capacity to place the load where it can do the most damage to the muscle.
This concept falls apart somewhat if you prefer to work with cables or machines in lieu of barbells or dumbbells. The consistent resistance curve from a cable attachment means that partial reps might lose a lot of their potency on exercises like the cable curl or lat pulldown.
Part and parcel with having the right equipment to make partial reps effective is picking the right exercises to go along with them. While most free weight movements could see some benefit from including partials, here are a few examples of exercises that are uniquely suited to pruning some motion and how to go about doing so.
- Lateral Raise: Cut out the bottom third of the movement.
- Preacher Curl: Stop curling when your forearm is perpendicular to the pad.
- Dumbbell Flye: Lower the weights before your arms are parallel at the top.
- Skull Crusher: Don’t fully extend your elbow at the top of each rep.
It’s worth pointing out that all of these exercises are isolation movements. Since compound lifts involve multiple joints — and thus multiple muscle groups — they may not always be the best way to utilize partial reps.
The Big Picture
Squat as deep as you can. Touch your chest when you bench if you’re able. Using all of your available range of motion will make you strong, keep your joints in fighting shape, and grow some muscle to boot.
But if you’re stuck in a rut or can’t bust through a stubborn plateau, the tactical implementation of partial reps might help you put the pedal to the medal. By removing the portions of the movement that don’t serve your needs, you can ratchet up the muscular tension or double down on technique practice — which means more gains down the road.
- Schoenfeld, B. J., & Grgic, J. (2020). Effects of range of motion on muscle development during resistance training interventions: A systematic review. SAGE open medicine, 8, 2050312120901559. https://doi.org/10.1177/2050312120901559
- Weiss, Lawrence & FRX, ANDREW & WOOD, LARRY & RELYEA, GEORGE & Melton, Charlie. (2000). Comparative Effects of Deep Versus Shallow Squat and Leg-Press Training on Vertical Jumping Ability and Related Factors. The Journal of Strength & Conditioning Research. 14. 10.1519/00124278-200008000-00001.
- Goto, M., Maeda, C., Hirayama, T., Terada, S., Nirengi, S., Kurosawa, Y., Nagano, A., & Hamaoka, T. (2019). Partial Range of Motion Exercise Is Effective for Facilitating Muscle Hypertrophy and Function Through Sustained Intramuscular Hypoxia in Young Trained Men. Journal of strength and conditioning research, 33(5), 1286–1294. https://doi.org/10.1519/JSC.0000000000002051
- Schoenfeld B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of strength and conditioning research, 24(10), 2857–2872. https://doi.org/10.1519/JSC.0b013e3181e840f3
- Newmire, Daniel E.1; Willoughby, Darryn S.2 Partial Compared with Full Range of Motion Resistance Training for Muscle Hypertrophy: A Brief Review and an Identification of Potential Mechanisms, Journal of Strength and Conditioning Research: September 2018 – Volume 32 – Issue 9 – p 2652-2664 doi: 10.1519/JSC.0000000000002723
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