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Range of Motion: Full or Partial
Len Kravitz, PhD

Introduction:
Commonly, in resistance training program design, personal trainers will follow scientific principles of training such us rest between sets, exercise order, intensity of the load, volume of sets and reps and frequency of training (Pinto et al, 2012). However, another variable of training that can be manipulated is range-of-motion (ROM). It should be noted that following certain surgeries or orthopedic injury a partial ROM is often utilized in the rehabilitation process (Pinto et al., 2012). However, some systems of training in the fitness industry purposely use a generous amount of partial ROM versus full ROM with many movements. A brief review of studies investigating these training variables provides some valuable findings for personal trainers.

Study 1: Pinto, R.S. et al. (2012) Effect of range-of-motion on muscle strength and thickness. Journal of Strength and Conditioning Research. 26(8), 2140-2145.
Purpose of the Study: The purpose of this study was to compare partial vs. full ROM upper-body resistance training on strength and muscle thickness in untrained males.

Volunteers: Forty young men, with no resistance training experience or clinical problems, were randomly assigned to a FULL ROM group (15 men, age=21.7 yrs), PARTIAL ROM group (15 men, age 21.7 yrs) and CONTROL group (10 men, age=24.5 yrs) for this 10-week study.

Testing/Training: Pre- and Post-Strength Tests: Maximal elbow flexion was tested using a full ROM biceps curl on a preacher curl device using standardized procedures to determine the 1RM.
Pre- and Post-Muscle Thickness Test: The right elbow flexors were measured for thickness using an ultrasound measurement technique, which is a non-invasive, reliable and safe method to measure muscle thickness.
Training: Supervised training, which was the same for both the FULL ROM and PARTIAL ROM groups, was conducted 2x/week for 10 weeks with a minimum of 48 hours between training sessions. Using a linear periodized training model, participants began with 2 sets of 20 repetitions (week 1 and 2) and progressed to doing 4 sets of 8 repetitions (weeks 9 and 10).
Using the preacher curl device, the FULL ROM group performed elbow flexion from 0° to 130° while the PARTIAL ROM group performed the flexion curl at 50° to 100°, which was identified as the mid-range of motion for the biceps curl action. The CONTROL group did not do any type of muscular fitness training. Other than biceps flexor exercises, the FULL and PARTIAL ROM groups reframed from any other formalized muscular fitness exercise during the study.

Results: In 1RM strength, the FULL ROM group improved 25.7% versus the PARTIAL ROM group, which improved 16.0%, while the CONTROL group showed 1.7% improvement. Muscle thickness improved 9.51% and 7.3% for the FULL ROM and PARTIAL ROM groups, respectively. The CONTROL group actually had a loss (-2.4%) in muscle thickness.

Take Home Message: For strength, the FULL ROM technique was superior to the PARTIAL ROM with this muscle group (elbow flexors) and sample population (untrained males). However, the PARTIAL ROM results were significant, suggesting that this is a variable of training that fitness professionals may elect to use.

Study 2. Massey, C.D. et al. (2005). Influence of range-of-motion in resistance training in women. Early phase adaptations. Journal of Strength and Conditioning Research, 19(2), 409-411.
Purpose of the Study: The purpose of this study was to compare partial versus full ROM for the development of maximal upper-body strength in women.

Volunteers: Twenty-nine college-aged females, describe as occasional lifters with limited resistance training experience, were randomly assigned to a FULL ROM group (13 women), PARTIAL ROM group (8 women) and a MIXED ROM group (8 women) for this 10-week study.

Testing/Training: Pre- and Post-Strength Test: A full ROM 1RM bench press was used as the principle measurement for this study.
Training: For this supervised 2days/week ROM study with the bench press, the full ROM group completed 3 sets of bench press. The partial ROM group trained with 3 sets that were 2 to 5 inches from full extension of the elbows. The MIXED ROM group trained with a combination of partial and full ROM sets. To match training loads, the MIXED ROM group completed 2 partial ROM sets and 1 full ROM set for the first 5 weeks and then completed 1 partial ROM set and 2 full ROM sets for the last 5 weeks of the study. All bench-training protocols incorporated 15 repetitions, with loads progressively increased in 5 lb increments as the volunteers increased their muscular fitness. Initially, the full ROM group trained at 65% of the volunteers' 1RM while the partial ROM group trained at 100% of the volunteers' 1RM. The authors cited previous research indicating that the upper portion of the bench press lift is considered to be the strongest ROM. Therefore, that higher percentage of 1RM for the partial ROM group was deemed appropriate for this study. Also, on training days all volunteers in this study completed 3 sets of the following exercises: squat (10 reps), upright row (15 reps), standing biceps curl (10 reps), latissimus dorsi pulldown (10 reps), crunches (15 reps), leg curls (12 reps) and calf heel raises (12 reps).

Results: Results of the study, as depicted in Table 1 reveal that the FULL ROM training group improved significantly better then the PARTIAL ROM and QUASI-CONTROL group. However, each of the training groups demonstrated a meaningful increase in 1RM bench press.
Take Home Message: All three training groups showed an impressive increase in muscular strength. Although superior 1RM bench press results (in this untrained college-aged female population) were observed with the FULL ROM group, the PARTIAL ROM and MIXED training groups distinctively increase their 1RM strength. These results indicate that the combination of FULL and PARTIAL ROM training can be considered a suitable variable to incorporate in a resistance-training program

Summary Thoughts
As noted previously, several methods of training in the fitness industry incorporate a great deal of partial ROM movements. Results from both of the studies reported show an increased muscular fitness and muscle thickness will result from incorporating this variable of training. Alas, fitness professional currently utilizing partial range of motion should feel empowered that this training is beneficial. However, it should be highlighted from both of the reviewed studies, when incorporating the partial ROM training it may be more effective and preferable to target the strongest part of a lift. This will likely elicit the best outcome in muscular strength and muscle adaptation. Additionally, Massey and colleagues (2005) discuss that other well-known professionals in the field of resistance training recommend that partial ROM training should be included for optimal athletic sport performance, too. This assertion is made due to the fact that many sports movements (such as a soccer kick or baseball throw) are actually partial range of motion movements. Pinto et al. (2012) suggest that fitness professionals and strength training coaches use full ROM training in the early phases of a person's training. Since partial ROM is more effective at the strongest part of an exercise, with higher loads, this type of training may be preferably presented in a latter phase of adaptation for a recreational client or competitive athlete. Lastly, for variety in the training stimulus for seasoned resistance training enthusiasts, incorporating a mixed exercise design of partial and full ROM exercises appears to be a practical and effective option.

Bio: Len Kravitz, PhD, CSCS, is the program coordinator of exercise science at the University of New Mexico, where he received the Outstanding Teacher of the Year and Presidential Award of Distinction. In addition to being a 2016 inductee into the National Fitness Hall of Fame, Len was awarded the 2016 CanFitPro Specialty Presenter Award.