To Stretch or Not To Stretch?

Static stretching (SS) has formed parts of regular training, recovery, physiotherapy, pre-match warm-ups and cool-downs for years. It is often thought that static stretching can help:

• Improve flexibility
• Enhance physical performance
• Prevent injury
• Improves recovery from injury

Research suggests that other forms of training such as strength training can achieve these effects just as effectively if not more effectively than static stretching.

So, does all this stretching really provide that many benefits? Or are we just wasting our time?

There is consistent evidence that SS increases flexibility in the short-term, although the gains in flexibility decrease relatively quickly, such that they are lost within 30 minutes!^1,2 There is also evidence to suggest that prolonged static stretching performed regularly over several weeks can result in meaningful improvements in range of motion (ROM).^3,4

However, the same can be said for strength training where flexibility is also increased by, especially eccentric training. The magnitude of increase achieved appears to be close to that achieved through static stretching. Strength training also seems to increase muscle mass, bone mass, strength, decreased risk of falls and other benefits.^{5, 6}

So, stretching doesn’t seem to have any superior benefits in ROM when compared to strength training. But what about its impact on performance?

Many recent studies and reviews have reported that sustained static stretching before performance either reduces max strength, power, plyometric ability, balance and agility or has no effect on performance.^{7, 8} It also seems that the longer the sustained static stretch the greater the negative impact is on performance.⁸ 

So what about its effects on endurance performance? Well, stretching doesn’t seem to improve running or walking efficiency. Direct impact on endurance performance is uncertain with stretching whereas strength training has been shown to consistently improve endurance.^{9, 10}

Okay, so what about injury prevention or as a treatment modality?

Several studies have suggested that decreased flexibility at baseline of injury or stretching less often, may predispose to injury. However, many recent studies have struggled to find any relationship between static stretching and injury prevention. Several systematic reviews have concluded that there is not enough evidence to either support or discontinue the use of stretching for injury prevention.^{11, 12}

Other forms of training and treatments seem to consistently show to reduce injury rates with Laursen et al mentioning that “consistently favourable estimates were obtained for all injury prevention measures except for stretching.” ¹³ This study showed that progressive strength training reduced injury rates to less than a third!

In terms of making the recovery process quicker, studies have shown that performing static stretching for 2x a day reduces time until return to sport by around 2 days or longer.¹⁴ In contrast an eccentric strengthening program out performed a traditional program with a mix of static stretching, concentric and eccentric exercises, with return to sport being 23 days less!

So, is there any point in stretching?

Absolutely! It seems that static stretching helps improve flexibility both in the short and long term and can be a lot more easily tolerated in the acute phases of injury and more accessible to a lot of people. However, it seems that there are other ways in which we can improve flexibility, such as eccentric strengthening which proposes other benefits aside from just flexibility. When it comes to improvements in performance it is unclear if there are any positive effects. There is evidence to suggest that prolonged static stretching before activities can hinder performance and should be avoided before explosive activities and substituted for a more active warm-up. In the long term, effects on performance are equivocal whereas strength training has been shown to improve performance. It also seems that static stretching has minimal effect on injury prevention in contrast to strength training typically involving an eccentric component where injury and time returning to sport is reduced.

My view? Use stretching as a form of training when flexibility is the goal you’re working towards or is specifically needed for your activity/sport such as gymnastics or dancing. That being said, it shouldn’t make up the bulk of your program and you should look to implement strength training over stretching in the majority of cases. 

References

1. de Weijer VC, Gorniak GC, Shamus E. The effect of static stretch and warm-up exercise on hamstring length over the course of 24 hours. J Orthop Sports Phys Ther 2003; 33:727-733.
2. DePino G, Webright W, Arnold B, Duration of maintained hamstring flexibility after cessation of an acute static stretching protocol. J Athl Train 2 2000; 35:56-59.
3.  Harvey L, Herbert R, Crosbie J. Does stretching induce lasting increases in joint ROM? A systematic review. Physiother Res Int2002; 7:1-13.
4. Bandy WD, Irion JM, Briggler M. The effect of static stretch and dynamic range of motion training on the flexibility of the hamstring muscles. J Orthop Sports Phys Ther 1998; 27:295-300.
5. Lauersen JB, Andersen TE, Andersen LB, Strength training as superior, dose-dependent and safe prevention of acute and overuse sports injuries: a systematic review, qualitative analysis and meta-analysis. British Journal of Sports Medicine 2018;52:1557-1563.
6. 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. 
7. Behm D, Bambury A, Farrel C, Power K. Effect of acute static stretching on force, balance, reaction time, and movement time. Med Sci Sports Exerc 2004; 36:1397-1402.
8. Kay AD, Blazevich AJ. Effect of acute static stretch on maximal muscle performance: a systematic review. Med Sci Sports Exerc 2012; 44:154-164.
9. Saunders PU, Telford RD, Pyne DB, Peltola EM, Cunningham RB, Gore CJ, et al. Short-term plyometric training improves running economy in highly trained middle and long distance
10. Nelson A, Kokkonen J, Eldredge C, Cornwell A, Glickman‐Weiss E. Chronic stretching and running economy. Scand J Med Sci Sports 2001; 11:260-265.
11.  Herbert RD, Gabriel M. Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review. BMJ 2002; 325:468.
12. Schiff MA, Caine DJ, O’Halloran R. Injury prevention in sports. Am J Lifestyle Med 2010; 4:42-64.
13.  Lauersen JB, Bertelsen DM, Andersen LB. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med 2014; 48:871-877
14. Malliaropoulos N, Papalexandris S, Papalada A, Papacostas E. The role of stretching in rehabilitation of hamstring injuries : 80 athletes follow-up. Med Sci Sports Exerc 2004; 36:756-759.