Jackie Haffey and Matt Ballman
Have you ever wondered why stretching was always emphasized so heavily in gym classes growing up? Stretching is something that has been coupled with exercise all of our lives. Growing up we are taught to stretch before and after exercise in order to help prevent injury, promote recovery, and enhance your overall performance, but does it actually work? There are professional athletes out there who undergo strict training regimens that involve lots of stretching, but still manage to have career altering injuries like tearing their ACL. There are many athletes who are out there that are very talented but almost never stretch before or after a workout. On the flipside, there are many professional athletes out there that vow that stretching helps them extend their careers and improve recovery. In the NBA, yoga has become a common practice among players doing all that they can in order to help their bodies sustain their elite level of play and handle the rigors of playing in an 82 game season. Arguably the best player of all time Lebron James practices yoga regularly . He even attributes it to helping him extend his career and play at a high level for as long as he has . So does stretching actually help people perform better or avoid injury or is it all just a myth?
For a long time, stretching was highly recommended with little evidence to support it. Now studies are showing that acute stretching before exercise can actually be harmful as discussed in the previous blog post, “Holding Your Stretch is Holding You Back”. So what is evidence saying about chronic stretching?When discussing effects of chronic stretching, it is referring to long term effects of consistent stretching. People normally associate this with increasing flexibility, or joint range of motion (ROM). The American College of Sports Medicine (ACSM) has recommendations for maintaining flexibility. A study was done in 2010 to support the ACSMs advice specifically for hip flexion . There was a significant improvement in ROM for all stretching groups and a decrease for the control group . The paper did mention its own limitation in only studying one muscle group, saying its findings should not be generalized to any muscles in the body. Another limitation was that the participants could not start a new or increase intensity of an existing exercise program during the study . This may have allowed the collected data to have less noise but it may not accurately translate to real world scenarios as many athletes aim to increase workout intensity or switch up their workout programs. So with the knowledge that chronic stretching can increase ROM, how does it affect performance?
A study completed in 2007 had the goal of determining the effects of chronic stretching on specific exercise performances. Performed on relatively inactive people, the study lasted eight weeks long and tested whether stretching had an impact on power, strength, and endurance in the lower body by using various exercises according to each fitness category . The, “stretching,” or experimental group showed significant improvement in all categories whereas the control group showed no improvements . On the contrary there was a study completed on hamstring performance in female D3 athletes . Six weeks long, this study found there to be no significant difference in power performance in either the stretching and control groups . So maybe stretching just has an effect on sedentary individuals?
Another aspect of stretching that is renowned is its ability to decrease the body’s risk of injury. A study completed on patients with chronic neck pain had subjects undergo 6 weeks of stretching and/or global posture reeducation twice a week during that time . After the study was completed it was found that both the stretching and posture reeducation groups had significant reduction in pain . However, this study also lacked a control group so it is hard to tell whether the reduction in pain was at the result of a placebo effect. On the opposite end, a large scale literature search evaluated over 90 different studies trying to determine whether there was sufficient evidence that stretching does indeed reduce the risk of injury . After reviewing a large amount of literature it was found that it cannot be determined whether stretching reduces the risk of injury . In fact, it found it is more than likely to not have anything to do with injury risk because stretching depends on different characteristics of muscles than characteristics that rely on eccentric movement which is often the movement where non-contact injuries occur .
After reviewing the above literature and evaluating research that studied chronic stretching it really cannot be determined whether chronic stretching is essential in order to maintain performance and prevent injury. All of the studies observed either could not find data to support the fact that stretching indeed plays a pivotal role in exercise or the study was to limited in its structure to provide accurate results. The biggest problem was how the term, “chronic,” is defined. The longest study that we found was only 12 weeks long which can hardly represent professional athletes who have been stretching throughout their entire lives. Without longer studies it’s hard to determine anything about chronic stretching because there’s simply not enough data out there. Although stretching cannot be supported with factual scientific data it is hard to argue that it can’t hurt to stretch after exercise. With successful athletes swearing by its benefits why could it hurt to spend a little time after you exercise to stretch out? Even if it’s just for peace of mind stretching does have at least some benefit after all.
Questions to Consider:
In what populations is it most important to determine the effects of stretching?
Since most current studies are on the lower extremities, should studies been done on the effect of stretching the upper extremities ?
What would be your personal definition of chronic? Do you think 6 or 8 or 12 weeks studies count towards data for the effects of chronic stretching?
References and Further Readings:
- Kokkonen ’ J, Nelson AG, Eldredge C, et al. Chronic Static Stretching Improves Exercise Performance Chronic Static Stretching Improves Exercise. Performance Med Sci Sport Exerc. 2007;39(10):1825-1831. doi:10.1249/mss.0b013e3181238a2b.
- Aure OF, Hoel Nilsen J, Vasseljen O. Manual Therapy and Exercise Therapy in Patients With Chronic Low Back Pain. Spine (Phila Pa 1976). 2003;28(6):525-531. doi:10.1097/01.BRS.0000049921.04200.A6.
- Shrier I. 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. 1999;9(4):221-227. https://www.colorado.edu/intphys/iphy3700/shrierCritRev.pdf. Accessed May 7, 2018.
- Bazett-Jones DM, Gibson MH, McBride JM. Sprint and Vertical Jump Performances Are Not Affected by Six Weeks of Static Hamstring Stretching. J Strength Cond Res. 2008;22(1):25-31. doi:10.1519/JSC.0b013e31815f99a4.
- Sainz de Baranda P, Ayala F. Chronic Flexibility Improvement After 12 Week of Stretching Program Utilizing the ACSM Recommendations: Hamstring Flexibility. Int J Sports Med. 2010;31(6):389-396. doi:10.1055/s-0030-1249082.
- Toland S. The Rise of Yoga in the NBA and Other Pro Sports | SI.com. Sports Illustrated. https://www.si.com/edge/2014/06/27/rise-yoga-nba-and-other-pro-sports. Published 2014. Accessed May 7, 2018.
To answer one of your questions, I think stretching would be most important in groups of people who only occasionally exercise due to the combination of them not being consistently exercising and already stretching at some level because they are at risk to injury if they are just coming off of the couch. Answering the last question, chronic stretching would be more on the scale of 6 – 12 months, and I would count them as good starting points for the studies, with 12 weeks being on the shorter end of chronic.
I am surprised at the studies not showing significant differences due to stretching, since, as is mentioned, it is preached by most coaches and athletes as a key component to not getting injured.
I found this topic very interesting since whenever I exercise I almost never stretch beforehand. I personally think that the 3-month study is not enough to truly show any chronic effects of stretching, and would prefer a 6 or even 12-month study, as Dan also suggested. I think it is difficult to truly determine whether stretching can prevent injury since there are so many other factors in sports injuries, especially in contact sports.
Addressed in “Holding Your Stretch is Holding You Back”, it talks about dynamic stretching being beneficial for many athletes and can be manipulated in ways to best suite their workout. Personally, static stretching always put me in the zone before I started training and dynamic stretching served as a method to loosen my muscles and better prepare. Even though studies do not defend static stretching, I feel that with a combination of of static and dynamic stretching you can best prepare your body for your workout.
Agreeing with Andrew, I think part of peak performance is due to mental state, and stretching also helps me get in the zone. I think if stretching feels good, its a good idea to stretch before/after activity. Stretching to the point of pain is not beneficial, and might be the reason some people do not like to stretch before exercise.
To answer another one of your questions, I think it would be helpful to examine stretching of the upper extremities. I agree that you can’t really conclude much from this research, and therefore I think it would beneficial to not only increase the amount of studies conducted, but to also broaden the scope of what these studies examine, as we really should be concerned with the whole body.
Was any of the stretching tested in the studies above dynamic stretching or just static stretching. In the Research Says “Holding your Stretch is Holding you Back” it was mentioned that dynamic stretching may be more beneficial for the athlete; and I didn’t know if that was also applicable to chronic stretching. In the studies that test if stretching reduces the risk of injury, is the injury being tested acute or long-term. I feel like stretching wouldn’t help something like an ACL tear, but might help cartilage stay lubricated (like Margot mentioned in her presentation) and prevent injuries related to that.
I feel as if the reason why this hasn’t been studied more is because of how complex it would be to actually study the chronic effects of stretching. No matter the length study done, it would take a great deal of control in order to single out stretching being the reason for an increase in performance. I feel like you also have to personalize the sport you are trying to see if stretching is beneficial. Stretching for a weight lifter may not be as beneficial as a gymnast who stretches to increase their flexibility. While chronic stretching doesn’t seem to increase performance it also doesn’t seem to hurt performance either so it can’t hurt to stretch.
Building off of the 2007 study “Chronic Static Stretching Improves Exercise Performance”, I’d be interested to dive further into the effects between endurance or more anaerobic athletes. This study looked at “relatively inactive” people which I’m not really sure how many conclusions we can draw from an 8 week study for “chronic stretching”. The study on the D3 female athletes did address this, but i’d still be interested to see if there’s a difference in results depending on the sports they play.
To answer one of your questions, I think over 12 weeks would be a better indicator if stretching is beneficial or not. From personal experience, when I did physical therapy for my back it took about 6 months of stretching combined with exercise to see a difference. However, this was to recover from an injury, and when I didn’t stretch the pain was worse. I think chronic stretching could be beneficial for an athlete, but the affects of stretching would only be noticeable after repeated months of stretching.
As a couple other people mentioned, I think it would be more interesting to look at even longer term effects of stretching. It would be great if 12 months of stretching reduced risk of injury, increased flexibility, etc, but I wonder how the data would look after 12 years, for example. Outside of sports medicine, mindful stretching is advised for older patients as well. I’ve heard people praise yoga, in particular, for maintaining bone & muscle health in elderly patients, but I wonder if there is concrete evidence in the literature to support this claim.
I agree with Erin, I think a study about the dynamic and static stretching in yoga would be very interesting. I do yoga very frequently and it is the best at realigning my posture and relaxing my muscles. I’ve noticed that doing yoga in conjunction with other exercises improves my performance in them. I wonder if carrying out certain “flows” improves performance more than others and what makes these poses so effective.
I believe whole heartedly that stretching, with correct form, DOES prevent some injuries, because if you are increasing range of movement and muscles are relaxing after being exhorted during a sport, that this can help. I have seen myself (in the past) and currently my daughter straining muscles because she has tight muscles in one area, so the other areas are compensating, therefore, there is an increase in the possibility of injury. She has been diagnosed by a Physical Therapist, who does a full evaluation of which areas are weak and which are strong.