066: Long-Term Stretching Can Reduce Musculotendinous Injuries But Effects on All-Cause Injury Risk Are Insignificant

Article Reviewed

Behm, D. G., Kay, A. D., Trajano, G. S., et al. (2021.) 'Effects of Stretching on Injury Risk Reduction and Balance.' Journal of Clinical Exercise Physiology volume 10, number 3, pages 106-116.

Article Summary

This narrative review revealed that the lack of consistent evidence for a protective effect of stretching on injuries reported in many studies is probably because of the type of injuries that were investigated. Studies that found no positive effect of stretching on injury risk tend to examine all-cause injury risk (e.g., fractures, cartilaginous injuries, and joint inflammation, among many others). However, when researchers specifically investigate strain-related musculotendinous injury risk, they often report positive effects of both pre-exercise and chronic static passive stretching - especially in explosive and sprint activities - with longer-term stretching appearing to have more of an impact (possibly because it causes greater tissue compliance). Acute and chronic dynamic stretching have minimal, if any, positive impact on injuries of any type.

Detailed Breakdown

 There is no question about the ability of stretching to increase joint range of motion (ROM), which can improve physical performance in sports that demand the ability to display large amplitudes of movement, such as gymnastics, figure skating, and combat sports (Behm et al., 2020). Stretching to improve ROM also positively affects daily living activities, such as putting on shoes and socks or bending to pick up an object from the ground (Gonzalez-Rave et al., 2012). This increase in ROM was also traditionally purported to reduce the risk of injury (Witvrouw et al., 2004), but the literature lacked consistent evidence to support this notion (Radford et al., 2006).

However, closer examination of studies reporting no positive effect of stretching on injury risk shows that they often investigate all-cause injuries (Shrier, 2004; Small et al., 2008). All-cause injuries include such events as bone fractures, cartilage tears, joint swelling, and many others (Baker et al., 2019). Given the very specific nature of adaptations following stretching, such as increased ROM and greater tissue compliance, it makes little sense to expect stretching to have a significant impact on injuries like fractures, which tend to occur following high impacts involving very high forces.

This narrative review reported that stretching can positively affect specific types of injuries, namely those caused by high levels of strain within the muscle-tendon unit (i.e., muscle strains and ligament sprains). For example, the authors cited Behm et al. (2016), who reported an average 54% reduction in MTU injuries following acute pre-exercise static passive stretching. Similarly, they cited McKay et al. (2001), who monitored over 10,000 basketball players and found that individuals who did not perform pre-game stretching were 2.6x more likely to suffer ankle injuries than players who did stretch. Chronic (long-term) stretching seemed to magnify the protective benefits, such as that reported by Woods et al. (2007), who concluded that chronic static passive stretching - with or without a warm-up - before exercise is associated with a lower incidence of MTU injuries.

While it may be tempting for individuals who dislike stretching as a form of physical training to point to studies that investigated all-cause injuries and declare, "Stretching doesn't prevent injury!", it is important that the nuance of the matter is communicated to members of the audience who are interested in this subject and explain the potential protective benefit that static passive stretching may confer to specific types of injuries.

References

Baker, H. P., Lee, K. Y. H., Dayton, S. R., et al. (2019.) 'Thursday Night Football's Impact on All-Cause Injuries in NFL Players During 2012-2017.' The Physician and Sports Medicine volume 47, number 3, pages 350-352.

Behm, D. G., Blazevich, A. J., Kay, A. D., et al. (2016.) 'Acute Effects of Muscle Stretching on Physical Performance, Range of Motion, and Injury Incidence in Healthy Active Individuals: A Systematic Review.' Applied Physiology, Nutrition, and Metabolism volume 41, number 1, pages 1-11.

Behm, D. G., Kay, A. D., Trajano, G. S., et al. (2020.) 'Mechanisms Underlying Performance Impairments Following Prolonged Static Stretching Without a Comprehensive Warm-Up.' European Journal of Applied Physiology volume 121, pages 67-94.

Gonzalez-Rave, J. M., Sanchez-Gomez, A., & Santos-Garcia, D. J. (2012.) 'Efficacy of Two Different Stretch Training Programs (Passive vs. Proprioceptive Neuromuscular Facilitation) on Shoulder and Hip Range of Motion in Older People.' Journal of Strength and Conditioning Research volume 26, number 4, pages 1045-1051.

McKay, G. D., Goldie, P. A., Payne, W. R., et al. (2001.) 'Ankle Injuries in Basketball: Injury Rate and Risk Factors.' British Journal of Sports Medicine volume 35, number 2, pages 103-108.

Radford, J. A., Burns, J., Buchbinder, R., et al. (2006.) 'Does Stretching Increase Ankle Dorsiflexion Range of Motion? A Systematic Review.' British Journal of Sports Medicine volume 40, number 10, pages 870-875.

Shrier, I. (2004.) 'Does Stretching Improve Performance? A Systematic and Critical Review of the Literature.' Clinical Journal of Sport Medicine volume 14, number 5, pages 267-273.

Small, K., McNaughton, N. L., & Matthews, M. (2008.) 'A Systematic Review into the Efficacy of Static Stretching as Part of a Warm-up for the Prevention of Exercise-Related Injury.' Research in Sports Medicine volume 16, number 3, pages 213-231.

Witvrouw, E., Mahieu, N., Danneels, L., et al. (2004.) 'Stretching and Injury Prevention: An Obscure Relationship.' Sports Medicine volume 34, number 7, pages 443-449.

Woods, K., Bishop, P, & Jones, E. (2007.) 'Warm-up and Stretching in the Prevention of Muscular Injury.' Sports Medicine volume 37, number 12, pages 1089-1099.