Partial Vs. Full Range of Motion Reps - Which is Best?

I’m surely not breaking any new ground by stating that the manner in which you perform an exercise (i.e., technique) will have a profound impact on results. One aspect of technique that varies substantially between lifters is range of motion (ROM), which can be defined as the extent of movement of a given joint during exercise performance. Some lift through the complete ROM of an exercise, while others restrict training within a limited range. In some cases this is a haphazard decision that involves little thought; never a smart tactic when the goal is max muscle development. Clearly, a scientific approach can and should be adopted to optimize results.

Opposing opinions have been proposed as to whether a partial or complete ROM is best for increasing hypertrophy. The mainstream approach is to take every rep through its full excursion.³ Because lengthening and shortening of fibers is optimized, this is theorized to work muscles in a manner that maximally stimulates their growth. Alternatively, others dispute this contention and claim partials are the way to go.¹¹ Proponents of this strategy propose that heavy-load training in a muscle’s strongest range— where leverage is greatest— will produce optimal increases in muscle mass over time.

Who’s right? Fortunately, several studies have been carried out to provide insight on the topic.

Full ROM for Maximal Muscle Hypertrophy

In a study comparing full versus partial ROM in the upper body, Brazilian researchers had subjects perform preacher curls at either 0-130 degrees (full range) of elbow flexion, or 50-100 degrees (partial range) of elbow flexion.⁸ The program employed a progressive overload strategy, with the number of sets increasing from two to four, and the reps decreasing from 20-repetition maximum (20RM) to 8RM, over the course of the 10-week protocol. Despite a 36 percent lower volume of training for those performing curls with a full ROM, these subjects achieved markedly greater growth of the biceps brachii compared to the partial ROM group, as assessed by effect size (a statistic intended to determine the practical “meaningfulness” of results). In fact, the effect for training through a full range was almost double that of using a partial ROM!

A more recent study investigated the hypertrophic effects of lower body training with different ROMs.¹ Subjects were randomly assigned to perform either deep squats (0-120 degrees of knee flexion) or shallow squats (0-60 degrees of knee flexion), with training carried out three days a week for 12 weeks. Importantly, loading was equated between groups so that each condition was carried out at its respective repetition maximum (i.e., heavier loads were used in the shallow squat condition). Results showed that lean body mass of legs significantly increased in the deep squat group, while no change was observed in the shallow squat group. Of particular interest was the fact that deep squats resulted in increases in muscle cross-sectional area across the entire frontal thigh, while shallow squats caused an increase only in the uppermost region. The combined findings of these studies, as well as that of other research⁶, indicate that the greater ROM produces more complete overall muscular development.

Training at Long Muscle Lengths Increases IGF-1

There appears to be something particularly beneficial about working through the bottom position of a movement, where the muscle is placed under a heightened stretch (i.e., long muscle length). In a novel research design, researchers divided subjects into two groups: one performed a variety of knee-extension exercises at a shortened ROM (0-50 degrees of knee flexion), while the other performed the same exercises at a lengthened position (40-90 degrees of knee flexion).⁵ Training consisted of three to four sets of 10 reps carried out three days a week. The loads were equated so that the total work performed was approximately the same between groups. After eight weeks of regimented training, the group performing the exercises at long muscle lengths displayed markedly greater growth in the quads, compared to the group training at short muscle lengths (53% versus 18%, respectively). What’s more, elevations in the anabolic hormone IGF-1 were significantly greater in long- versus short-length training (31% versus 7%, respectively), which implies that loaded exercise performed under a stretch stimulates greater metabolic and mechanical stress. Other research reports similar findings⁷, providing compelling evidence that training at longer muscle lengths has advantageous effects on building muscle.

So does this mean that partial ROM training should be avoided? 

Not necessarily.

There is clear evidence that muscle activation varies based on the joint angle during exercise performance. The quads, for example, show differing levels of muscle activity in the leg extension. Specifically, the vastus lateralis is most active during the initial portion of the lift, while the vastus medialis assumes a majority of the work as you approach lockout.¹⁰ A ROM-specific activation pattern also has been shown to occur during the biceps curl, with the short head showing greater activity in the activity of the long head during early movement, and increased activity in the short head during the latter phase.² These findings suggest that a combination of ROMs can have a synergistic effect on muscle development.

Heavy Training Using Partial ROM to Enhance Growth

Another factor to consider is that the ability to use heavier loads during partial-range movements where leverage is greatest enhances mechanical tension on the musculature. The magnitude of mechanical tension is believed to be a primary driving force in the hypertrophic response to resistance training.⁹ Accordingly, all other things being equal, some heavy training in a shortened range can potentially boost intracellular signaling responsible for increasing muscle protein synthesis. Moreover, the use of heavy loads in limited-ROM exercise has been found to translate into the ability to use more weight during full-range movements.⁴ This can serve to further enhance growth by increasing the amount of tension on muscles over the course of your training program.

So here’s what we can take home from a practical standpoint, when considering the research as a whole. The evidence is pretty clear that you need to train through a full ROM to derive maximal increases in muscle hypertrophy. Hence, the basis of your training program should include movements performed through a complete range, making sure to get a good stretch at the bottom position. That said, it can be beneficial to selectively integrate some partial-range movements into your program. Even just a few heavy-load sets per week, carried out in a muscle’s strongest range, can provide an added impetus for driving muscle growth.

Brad Schoenfeld, Ph.D., CSCS, FNSCA, is widely regarded as one of the leading authorities on training for muscle development and fat loss. He has published over 70 peer-reviewed studies on various exercise- and nutrition-related topics. He is also the author of the best-selling book, The M.A.X. Muscle Plan, and runs a popular website and blog at www.lookgreatnaked.com.

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