The Great Debate About Stretching

The Great Debate About Stretching By Chris Frederick, PT, KMI

“…conflicts between what therapists believed worked for them and what the researchers were saying was really happening in stretching.”

Stretching by By Pierre Selim, CC BY 3.0.

Introduction

The great controversy about stretching, particularly in therapy and athletics, started about 15 years ago (Shrier, 1999). Previously, it was assumed that stretching improved overall functional and athletic performance, increased specific flexibility and reduced injuries. A majority of clinicians and therapists as well as trainers and coaches from all disciplines were convinced about the importance of stretching as a necessary part of their protocols for successful outcomes.

An article titled The Stretching Debate featured invited commentary on research, that was largely negative, on the benefits of stretching (Chaitow, 2003). Many of these opinions, most of them by recognized manual therapists, were emotionally charged and reflected the conflicts between what therapists believed worked for them and what the researchers were saying was really happening in stretching. Since then, adamant pro and anti stretch camps have formed within professions practicing varietal therapies including fitness and sports coaches. This acrimonious climate has been taken advantage of in the media, adding more fuel to the fire (Reynolds, 2013). Consequently, the author of this article feels that it is extremely important to bring awareness to these facts and hopefully present a balanced, concise attempt to further explain and bring more light to the debate of stretching.

Negative outcomes in research

Injuries

In August 2002, an article appeared in The British Medical Journal that created a great deal of interest and controversy. The paper in question was a systematic review of research that evaluated the benefits (or lack of benefits) associated with stretching procedures in relation to protection from injury and post exercise soreness (Herbert & Gabriel). Conclusions taken directly from the study were “Stretching before or after exercising does not confer protection from muscle soreness. Stretching before exercising does not seem to confer a practically useful reduction in the risk of injury, but the generality of this finding needs testing.” (Herbert & Gabriel, 2002).

Six years after that study, another similar systematic review seemed to confirm the conclusions of the former. Namely, “There is moderate to strong evidence that routine application of static stretching does not reduce overall injury rates”. But there was an additional finding in that study that cast doubt on the concluding statement being taken at its word as a reliable and valid guide for using stretching in preventative therapy and training: “There is preliminary evidence, however, that static stretching may reduce musculotendinous injuries” (Small, 2008).

Strength, power and speed

There are many studies that demonstrate overall decreased parameters for strength such that many trainers and coaches do not allow stretching before weight training and other strength focused activities (Babault, 2010; Sekir, 2010, Manoel, 2008).

With regards to both power and speed, a study about the effects of stretching on sprinting is a good representation of what other studies have found. A repeated measures design was used, which consisted of the same group of 25 healthy, recreational runners completing a 40 yard sprint trial immediately following each of four different stretching conditions aimed at the iliopsoas muscle and lasting one minute each. In the no stretch condition, subjects improved significantly from pre- to post-sprint times. However there were no statistically significant differences in pre- and post-stretch sprint times among the static, ballistic and dynamic stretching conditions. The study concluded that sprint performance may show greatest improvement without stretching and through the use of a generalized warmup with walking as the activity. Obviously, these findings have clinically meaningful implications for runners who include iliopsoas muscle stretching as a component of their warm-up before running. For the record, similar negative results have been observed with various kinds of jumping (Behm, 2007).

The studies discussed above are several examples of negative outcomes with some studies even suggesting in their conclusions that stretching not to be performed as a therapeutic or training guideline. Taking a look at positive outcomes in stretch research may help to form a balanced opinion and approach using science to inform our practice.

Positive outcomes in research

In one study, authors found three positive results from stretching: “(i) there was steady-state force enhancement following stretch in voluntarily contracted muscles; (ii) some force enhancement persisted following relaxation of the muscle and (iii) force enhancement, for some stretch conditions, exceeded the maximum isometric force at optimal muscle length” (Lee & Herzog, 2002). This study counterpoints other studies concluding that stretching weakens force production in muscle and suggests further study to see how stretching may actually enhance muscle force production.

A recent systematic review on multiple studies indicated the following positive outcomes from stretching:

• Increased ROM.
• ROM increases bilaterally from unilateral stretch.
• Static and dynamic warm-ups are equally effective at increasing ROM prior to exercise.
• Pre-contraction stretching (e.g. PNF) lowers excitability of muscle.
• A pre-stretch contraction has been associated with greater acute gains in ROM compared to static stretching in many studies.
• In contrast to static stretching, dynamic stretching is not associated with strength or performance deficits.
• Dynamic stretching improved dynamometer-measured power as well as jumping and running performance.
• Static stretching performed before or after warm-up does not decrease strength.
• Four repetitions of 15-second holds of static stretching did not affect vertical jump.

Getting perspective on studies about stretching

There are many examples of a number of ubiquitous problems that is seen in research on stretching. One view is that one of the big problems in this and in many studies is that the word “stretching” is not adequately defined. Even after reviewing individual studies, the majority are only moderately specific about the type of stretching studied, e.g. most often “static” stretching. In the conclusions, it gets much worse as the general term “stretching” is used without qualifying it with a descriptor term, e.g. “static” (Thacker et al., 2004). The problem occurs when only the conclusions and not the details of studies like this are read (as is often the case), and the wrong impression is promoted. That is, all stretching is this or that when it should more accurately state, for example, “static stretching that utilizes the specific parameters used in this study is this or that”. This author believes this problem is one major source of misinformation about stretching in the news, other media and in professional journals that is prevalent.

It should be noted that much of the negative outcomes of studies on stretching over the past ten years has come from static stretch research (McHugh & Cosgrave, 2010). It should also be noted that the majority of stretch studies have attempted to isolate the stretch to one accessible muscle, most often the hamstrings (Slavko, 2013). “Static” and “the hamstrings” are obviously only two of a multitude of variables that can be studied and controlled in stretching research. Unfortunately, those are the two most common variables seen in research of stretching human tissue. Many other clinically relevant variables that can be applied in stretch therapy remain largely unstudied (Page, 2012). For example, the author has never seen a study that attempts to compare or differentiate any type of stretching applied to tonic versus phasic muscles. Therefore much of the negative press about stretching and the concomitant advice that has recently arisen from fitness and therapeutic sources appear to be limited at best and potentially harmful at worst. Much of this advice is seen as being derived from narrow, evidenced-based studies and not from systematic reviews comparing multiple methods or approaches to clinical assisted stretching much less self-stretching.

What may be an even bigger problem with using outcomes of research studies to guide clinical practice is disturbing evidence that has recently come to light. As reported in a Wall Street Journal article, “most results, including those that appear in top-flight peer-reviewed journals, can’t be reproduced” (Naik, 2011). Bruce Alberts, editor of Science magazine was quoted in that same article: “It’s a very serious and disturbing issue because it obviously misleads people who implicitly trust findings published in a respected peer-reviewed journal”. As a result, he had that journal devote a large chunk of one of its issues to the problem of scientific replication (Jasny, 2011). The point to be made here is that the results of scientific studies can be viewed with respected suspicion just as much as an anecdotal report from a trusted colleague or mentor. One is not better or necessarily more accurate and certainly not more trustworthy than the other, if one is to believe the multiple sources that have recently exposed the fallibility of the scientific method.

With this being the case, if a clinician wants to use evidenced-based protocols in stretching, it is advised to follow the recommendations of study outcomes only to the specific degree they were derived. That is, it should not be assumed by the therapist that the outcomes are also valid, using one example, for muscles and/or other tissues not studied in research. Unfortunately, incorrect and potentially harmful assumptions and generalizations (and therefore incorrect advice) about stretching still abound in all fields.

Ian Schrier, MD, PhD a well-known researcher on stretching, concluded the following key points in his 2007 article Does Stretching Prevent Injuries?

• Stretching immediately before exercise is different from stretching at other times.
• Stretching immediately before exercise does not appear to prevent injury.
• Regular stretching that is not done immediately before exercise may prevent injury.

Obviously, the debate about stretching is far from over and the author enthusiastically encourages the reader to join in on this discussion.

We agree with a 2012 clinical commentary that discussed current concepts of muscle stretching interventions and summarized the evidence related to stretching as used in both exercise and rehabilitation. Noting both negative and positive outcomes from stretching as we just did, the article stated that several authors observed individual responses to stretching. For example, the effectiveness of type of stretching seems to be related to age and sex: men and older adults under 65 years responded better to contract-relax stretching, while women and older adults over 65 benefit more from static stretching. Another one: 60-second holds of static stretches were associated with greater improvements in hamstring flexibility in older adults compared to shorter duration holds. Growing studies like this suggest that stretching programs may need to be individualized for best outcomes. It has been this author’s observation in practice that this is indeed the case and that standard protocols in stretching and flexibility training are mediocre at best and harmful at worst.

Practical, reliable professional experience from one’s personal practice integrated with input from experienced colleagues or mentors, when needed, which is then informed by evidence in research is, in the author’s opinion, the best strategy for optimal client outcomes. It is important to note that while science is moving steadily forward in research of connective tissues and is producing findings that can be clinically very supportive of stretching used in different kinds of manual therapies, practical parameters for a broad range of clinical application sadly lag far behind. The many possibilities of multiple types of stretching combined with the application of multifarious parameters have yet to be studied. Some or even many of these may well yield positive outcomes. Practice-based evidence (along with credible backing from fascia research) has certainly produced many positive outcomes with stretching. We need both reliable and valid clinical anecdotes as well as good research for best outcomes with our clients.

Note: This article is an extract from Chris & Ann Frederick’s latest book Fascial Stretch Therapy (Handspring Books, 2014). Text Copyright Chris Frederick. Fascial Stretch Therapy (FST) shows how assessment, treatment and training are used in a variety of common circumstances encountered in manual therapy and athletic training. The book describes and shows the therapist or trainer how to integrate FST in their current practice, business or workplace to enhance what they already do and provide. Available at: www.terrarosa.com.au

References

Babault, N, et al. (2010) Acute effects of 15 min static or contract-relax stretching modalities on plantar flexors neuromuscular properties. J Sci Med Sport 13(2). Pp. 247–252.

Behm, D.G., Kibele, A. (2007) Effects of differing intensities of static stretching on jump performance. Eur J Appl Physiol 101(5). pp. 587–94.

Chaitow, Leon et al. (2003) The stretching debate. Journal of Bodywork and Movement Therapies 7(2). pp. 80–96.

Herbert, R. Gabriel, M. (2002) Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review. British Medical Journal 325. pp. 468–472.

Jasny, B.R. (2011) Again, and Again, and Again … Science. Available at: http://www.sciencemag.org/content/334/6060/1225. [Accessed: 19 December 2013]

Lee, H-D, Herzog, W. (2002) Force enhancement following muscle stretch of electrically stimulated and voluntarily activated human adductor pollicis. Journal of Physiology. 545.1. pp. 321–330.

Manoel, M.E. et al. (2008) Acute effects of static, dynamic, and proprioceptive neuromuscular facilitation stretching on muscle power in women. J Strength Cond Res. 22(5). pp.1528–1534.

McHugh MP, 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(2). pp. 169–181.

Naik, G. (2011) Scientists’ Elusive Goal: Reproducing Study Results. Wall Street Journal [Online]. Available at: http://online.wsj.com/article/SB10001424052970203764804577059841672541590.html [Accessed: 19 December 2013].

Page, P. (2012) Current concepts in muscle stretching for exercise and rehabilitation. Int J Sports Phys Ther. 2012. 7(1), pp. 109–119.

Reynolds, G. (2013) Do we need to stretch? [Online] N.Y. Times. Available at http://well.blogs.nytimes.com/2013/04/26/ask-well-do-we-need-tostretch/?comments#permid=36 [Accessed 4 November 2013].

Shrier, I. (1999) Stretching before exercise does not reduce the risk of local muscle injury: a critical review of the clinical and basic science literature. Clin J Sport Med. 9(4). pp. 221–227.

Schrier, I. (2007) Does Stretching Help Prevent Injuries? In: MacAuley, D., Best, T.M. Evidence-based Sports Medicine, 2nd ed., p. 36-53.

Slavko, R., Wüst, D., Schwitter, T., Schmidtbleicher, D. Static Stretching of the Hamstring Muscle for Injury Prevention in Football Codes: a Systematic Review. Asian J Sports Med. March 2013: 4(1): 1–9.

Small, K. et al. (2008) A systematic review into the efficacy of static stretching as part of a warm-up for the prevention of exercise-related injury. Res Sports Med. 16(3). pp. 213–31.

Sekir, U. et al. (2010) Acute effects of static and dynamic stretching on leg flexor and extensor isokinetic strength in elite women athletes. Scandinavian Journal of Medicine & Science in Sports. 20(2). pp. 268–281.

Thacker, S. B. et al. (2004) The Impact of Stretching on Sports Injury Risk: A Systematic Review of the Literature. Med. Sci. Sports Exerc. 36(3). pp. 371–378.

Chris Frederick has been a physical therapist/physiotherapist since 1989, focusing on manual therapy – particularly with integration of Fascial Stretch Therapy and Kinesis Myofascial Integration – along with personalized movement prescription to restore function. He has an extensive background in dance, both as a professional dancer of classical ballet, as well as being a practitioner in the specialty of dance physical therapy/physiotherapy. Chris is also well versed in the ancient movement and healing arts of tai chi and qigong. He is a coauthor with Thomas Myers of the chapter on stretching in the seminal book “Fascia: The tensional network of the human body”.

Chris and his wife Ann Frederick are both certified by Thomas Myers in Kinesis Myofascial Integration and are the authors of the popular book “Stretch to Win”, and the new book “Fascial Release Therapy”. They are  Directors of the Stretch to Win Institute at www.stretchtowin.com, where they offer certification training workshops in Fascial Stretch Therapy.