Although pre-exercise stretching is common practice for many elite and recreational athletes, recent studies have cast doubt on its effectiveness. In Estonia, too, there has been much debate, many questions, and differing opinions about the benefits of stretching, which is why we think discussion on this topic is important.

What is the purpose of stretching?

The purpose of stretching is to restore joint range of motion. Stretching increases flexibility, which in turn allows the joints to move through a greater range. It’s important to know that some sporting activities (for example, gymnastics) require more flexibility than others (for example, running)[1].

Different stretching techniques

There are several subtypes of stretching, but they are mainly divided into three: static, dynamic, and proprioceptive neuromuscular facilitation (PNF).

Static stretching: Holding a muscle in a position (usually at least 30 seconds or more) that produces mild discomfort.

Proprioceptive neuromuscular facilitation (PNF): Maintaining the stretch position while alternately contracting and relaxing the muscle. One of the best-known examples is the contract–relax–stretch method.

Dynamic stretching: Actively stretching the muscles with swinging, controlled movements in which the range of motion increases progressively while remaining within normal limits.

Ballistic stretching: Performing bouncing movements while in a stretched position.

*Most studies have examined static stretching; the other methods above have been researched less[1].

What happens during stretching?

A single bout of stretching has viscoelastic and neural effects. The viscoelastic effect appears as a reduction in passive stretch resistance (muscle stiffness) and an increase in joint range of motion[1]. In addition, a single stretch raises the pain threshold[2]. The neural effect involves a reduction in the activity of the nerve cells that activate the muscle[1]. With regular stretching we maintain what was achieved with a single session—flexibility, muscle elasticity, and the nervous system’s stretch tolerance; in other words, the nervous system further adapts to muscle stretching[1]’[3]’[4]. In addition, with chronic stretching (stretching regularly over several months), sarcomerogenesis—formation of new sarcomeres (the muscle’s functional, contractile unit)—has been observed, resulting in muscle lengthening[5]. Thus, in certain cases, regular stretching can improve muscle activation and performance[4].

How flexible should you be?

It depends on the activity—for example, ballet demands very good flexibility (i.e., joint mobility). Excessive flexibility, however, can reduce the ability of muscles and tendons to store and release energy, which is needed to generate strength and power when walking, running, and jumping (think of a spring). Too much flexibility can therefore diminish this “spring mechanism,” reducing the capacity to sprint, jump, or change direction quickly—so a ballet dancer’s flexibility training will not significantly improve a runner’s performance. Conversely, limited flexibility (restricted joint mobility) may increase the risk of muscle injury because the muscle cannot absorb energy sufficiently well[1].

Does pre-exercise stretching impair performance?

Studies show that pre-exercise static stretching makes muscles weaker and slower, which can be crucial in many sports[1]’[6]. This means that, for example, if a ball-sport athlete does only static stretching as a warm-up, their performance (sprinting, jumping ability) decreases by a few percent for about 20–30 minutes[7]. If static stretching is followed by a sport-specific warm-up that raises body temperature, performance is not impaired. Ballet dancers, on the other hand, need stretching before performing complex elements—although they may be slightly weaker, their performance improves markedly[8].

The performance-reducing effect of pre-exercise stretching may also be overstated. In the warm-up routines of recreational or everyday athletes, stretch holds are usually not long enough to cause substantial, long-lasting changes in muscle strength[9]. Research has also concluded that holding stretches for up to 30 seconds does not impair performance in speed–power sports[10].

Does pre-exercise stretching reduce injury risk?

Studies indicate that pre-exercise static stretching does not reduce injury risk, does not improve performance, and does not protect against exercise-induced muscle soreness[11]. Nor do pre- or post-exercise stretches have harmful effects. So if you enjoy stretching or it’s part of your routine, there’s no reason to stop.

Although stretching may slightly help prevent overuse-related ligament and muscle tears, strains, and sprains, the effect is very small[12]’[13]. Proper training planning is much more important!

When do injuries occur?

Muscle injury usually results from excessive load, typically when a muscle is stretched under heavy resistance—for example, while lowering a heavy weight. Injury arises not from limited flexibility but from decreased performance—that is, the muscle cannot generate sufficient force or activate in a timely and coordinated manner[14].

Should you stretch before and after training?

The decision should be based on the goal of the session. If the goal is to reduce injury risk, pre-exercise stretching alone is not helpful. In that case, it is more effective to actively warm up the muscles, gradually increasing the intensity. A typical warm-up lasts at least 10 minutes and includes light aerobic activity and dynamic stretches that mirror the movements to be performed in the upcoming training or competition. If the goal is to increase joint mobility or perform the splits, then stretching exercises should be used. For most everyday athletes, including or excluding pre-exercise stretches should be a personal choice. If you enjoy it, stretch; if not, don’t—what matters most is doing exercises and movements that take your joints through a full range of motion (for example, full squats, lunges, hanging knee tucks, etc.). Because stretching also helps normalize breathing and heart rate, it’s reasonable to include some stretching at the end of a workout[1].

Successful training!

Hanno Tikkerbär, physiotherapist

Clinic of Sports Medicine and Rehabilitation

Tartu University Hospital

Rannama Physiotherapy

Mati Arend, physiotherapist

Center for Sports Injury Prevention and Research

University of Tartu

Clinic of Sports Medicine and Rehabilitation

Tartu University Hospital

Referenced article: http://www.nhs.uk/Livewell/fitness/Pages/Do-I-need-to-stretch-before-or-after-a-run-or-sports-and-exercise.aspx

[1] McHugh, M. P. and Cosgrave, C. H. (2010), To stretch or not to stretch: the role of stretching in injury prevention and performance. Scandinavian Journal of Medicine & Science in Sports, 20: 169–181

[2] McHugh MP, Nesse M. Effect of stretching on strength loss and pain after eccentric exercise. Med Sci Sports Exerc 2008: 40(3): 566–573

[3] Kokkonen J., Nelson A.G., Eldredge C., Winchester J.B. Chronic Static Stretching Improves Exercise Performance. Medicine & Science in Sports & Exercise. 2007;39(10):1825–31

[4] Gonçalves, Diego Laureano, Pavão, Tiago Sebastiá, & Dohnert, Marcelo Baptista. (2013). Acute and chronic effects of a static and dynamic stretching program in the performance of young soccer athletes. Revista Brasileira de Medicina do Esporte, 19(4), 241–246

[5] Zöllner, A. M., Abilez, O. J., Böl, M., & Kuhl, E. (2012). Stretching Skeletal Muscle: Chronic Muscle Lengthening through Sarcomerogenesis. PLoS ONE,7(10), e45661.

[6] Johansson, P. H., Lindström, L., Sundelin, G. and Lindström, B. (1999), The effects of preexercise stretching on muscular soreness, tenderness and force loss following heavy eccentric exercise. Scandinavian Journal of Medicine & Science in Sports, 9: 219–225.

[7] McHugh MP, Nesse M. Effect of stretching on strength loss and pain after eccentric exercise. Med Sci Sports Exerc 2008: 40(3): 566–573.

[8] Reid DC, Burnham RS, Saboe LA, Kushner SF. Lower extremity flexibility patterns in classical ballet dancers and their correlation to lateral hip and knee injuries. Am J Sports Med 1987: 4: 347–352.

[9] Avela J, Finni T, Liikavainio T, Niemela E, Komi PV. Neural and mechanical responses of the triceps surae muscle group after 1 h of repeated fast passive stretches. J Appl Physiol 2004: 96: 2325–2332.

[10] Kay, A. D., & Blazevich, A. J. (2012). Effect of Acute Static Stretch on Maximal Muscle Performance: A Systematic Review. Medicine and Science in Sports and Exercise, 44(1), 154–164.

[11] Pope RP, Herbert RD, Kirwan JD, Graham BJ. A randomized trial of preexercise stretching for prevention of lower-limb injury. Med Sci Sports Exerc 2000: 32: 271–277.

[12] Amako M, Oda T, Masuoka K, Yokoi H, Campisi P. Effect of static stretching on prevention of injuries for military recruits. Mil Med 2003: 168: 442–446.

[13] Hadala M, Barrios C. Different strategies for sports injury prevention in an America’s Cup Yachting Crew. Med Sci Sports Exerc 2009: 41: 1587–1596.

[14] Tyler TF, Nicholas SJ, Campbell RJ, McHugh MP. The association of hip strength and flexibility with the incidence of adductor muscle strains in professional ice hockey players. Am J Sports Med 2001: 29(2): 124–128.