Strength training is as effective as stretching for improving range of motion: a systematic review and meta-analysis

Key Points

1. Optimizing muscle extensibility and joint range of motion is a goal across many rehabilitation and exercise programs.
2. This review found that strength training is as effective as stretching in generating improvements in range of motion.
3. Changes in joint range of motion involve physiological, structural, and neurological adaptations.

BACKGROUND & OBJECTIVE

Optimizing joint and muscle range of motion (ROM) seems to be a common goal across nearly all populations, regardless of age, physical endeavor, or injury history. Improvements in ROM take place through a number of physiological, structural, and neurological adaptations, including increased tolerance to stretch, augmented fascicle length, changes in pennation angle, and reduced tonic reflex activity (1, 2, 3).

Studies comparing the effects of strength training (ST) versus stretching on ROM present conflicting evidence and leave many questions unanswered. Reduced ROM and muscle weakness can be observed together in many common musculoskeletal pathologies, begging the question: should patients spend more time stretching, or strengthening?

While it is clear that ST has a greater influence on strength, balance, and function, it is not yet known whether it can also help to improve ROM to the same degree as stretching (4). The aim of this paper was to compare the effects of ST versus stretching on ROM in a heterogenous group of participants across a multitude of studies.

Improvements in ROM take place through a number of physiological, structural, and neurological adaptations.

Progressive strength training through a gradually increasing range of motion may result in a return to prior level of function more expediently than stretching alone.

METHODS

The authors performed a systematic review and meta-analysis using the PRISMA method. Following a rigorous selection process, the authors were able to identify 11 articles with a total of 452 participants eligible for the review. The articles selected reported on ROM of the hip, knee, shoulder, elbow, trunk, and cervical spine, with varying methods of both active and passive measurements.

RESULTS

In 7 out of 11 articles, both ST and stretching groups significantly improved ROM, and between-group differences were insignificant. In one article, ST significantly improved ROM measurements, and dynamic stretching did not lead to improvement of ROM. In another article, ST provided greater improvement in AROM compared to stretching, but the between-group differences were insignificant for PROM. And in two articles, neither ST nor stretching were shown to cause significant improvements in ROM.

None of the articles demonstrated a difference in ROM response by gender. Both ST and stretching consistently promoted ROM gains, but there was not a clear advantage to one versus the other. Overall, the totality of the results did not indicate a clear recommendation of ST versus stretching for the improvement of ROM.

LIMITATIONS

Risk of bias was shown to be high in 5 of the articles, due to deviations from intended interventions, missing outcome data, and insufficient results reported. On the contrary, risk of bias was low in the other 6 articles. As expected, there was high heterogeneity across the articles analyzed, resulting in non-specific recommendations on stretching vs. strength training.

Future research is warranted for subgroup analyses on specific populations. More detailed reporting is needed on the magnitude of stretching, and volume, intensity, and frequency of ST. A dose-response relationship is yet to be established for the effect of ST on ROM.

CLINICAL IMPLICATIONS

The results of this review indicate that ST is just as effective as stretching for improving ROM. While the two interventions do not demonstrate significant differences in their effect on ROM, there remains a strong case to endorse ST over stretching in the clinical dosing of therapeutic exercise. There are many cases where ST provides greater overall benefit than stretching due to its wide range of benefits. Adaptations associated with ST not seen with stretching include improved muscle mass, increased bone mass, decreased injury risk, decreased falls risk, and increased gait speed (5, 6, 7).

Patients presenting with acutely decreased ROM due to injury or joint derangement oftentimes present as weak and deconditioned (8). For example, a post-surgical ACL knee lacking full extension ROM most likely has deficits in quadriceps strength and neurological drive; and a hamstring lacking extensibility after a grade II strain is most likely presenting with weakness. Appropriately dosed and progressive ST through a tolerable and gradually increasing range of motion may result in improved function and a return to prior level of function more expediently than stretching alone.

The variables of ST should be methodically progressed, with careful attention paid to the length-tension relationship and total strain on the muscle group, joint position, contraction type, contraction speed, volume, frequency, and relative intensity of the exercise. In a clinical setting, many exercises will likely need to be modified in order to accommodate positional and movement intolerances and sensitivities typically seen in an injured population. Due to the similar impact on ROM, and the clear advantage in improving many other physiological capacities, ST appears to be a superior clinical intervention for cases where deficits in range of motion are present.

+STUDY REFERENCE

Afonso J, Ramirez-Campillo R, Moscao J, Rocha T, Zacca R, Martins A, Milheiro A, Ferreira J, Sarmento H and Manuel Clemente F (2021) Strength training is as effective as stretching for improving range of motion: A systematic review and meta-analysis. MetaArXiv.

SUPPORTING REFERENCE

1. Sharman MJ, Cresswell AG, Rie S. (2006). Proprioceptive neuromuscular facilitation stretching: mechanisms and clinical implications. Sports medicine.
2. Kudo S, Sato T, Miyashita T. (2020). Effect of plyometric training on the fascicle length of the gastrocnemius medialis muscle. J Phys Ther Sci.
3. Guissard N, Duchateau J. (2004). Effect of static stretch training on neural and mechanical properties of the human plantar-flexor muscles. Muscle Nerve.
4. Morton SK, Whitehead JR, Brinkert RH, Caine DJ. (2011). Resistance training vs. static stretching: effects on flexibility and strength. J Strength Cond Res.
5. Lauersen JB, Andersen TE, Andersen LB. (2018). Strength training as superior, dose-dependent and safe prevention of acute and overuse sports injuries: a systematic review, qualitative analysis and meta-analysis. Br J Sports Med.
6. Lee IH, Park SY. (2013). Balance improvement by strength training for the elderly. J Phys Ther Sci.
7. Nicholson VP, McKean MR, Burkett BJ. (2015). Low-load high-repetition resistance training improves strength and gait speed in middle-aged and older adults. J Sci Med Sport.
8. Trakis JE, McHugh MP, Caracciolo PA, Busciacco L, Mullaney M, Nicholas SJ. (2008). Muscle strength and range of motion in adolescent pitchers with throwing-related pain: implications for injury prevention. Am J Sports Med.