Several months ago, I was giving a talk on injury prevention to a local triathlon club. Near the end of the talk, I was asked a question about dynamic stretching. This question tripped me up a little. In preparation for my talk, I had been researching why certain types of exercises are preferable to others. At the same time, I was working on my blog post regarding warming up and cooling down. In my research for both my upcoming talk, and my post I had started to read up on stretching.
In my younger years as a high school, collegiate and club level athlete I had thought that stretching was good. I would stretch both before and after my runs. During my career as a physical therapist, I had prescribed stretching to my patients with the intent of improving their mobility.
Why were we stretching in the first place?
There are two theories behind stretching, especially stretching before a workout or event. One is that stretching will increase the range of motion, or the amount that a join moves, so that it is sufficient enough to perform the activity efficiently. For example, efficient running gait requires that one have a certain amount of ankle, knee and hip flexibility. The other theory is that decreasing muscle stiffness will also decrease the rate of injury.
Why are we confused?
The research on stretching has been somewhat mixed. Part of the reason for this result may be that the definition, duration, frequency and intensity of stretching can vary greatly. If you have ever done research, you know that it involves asking a very specific question and studying the question under the assumption that there is no difference (i.e. that the null hypothesis is true).
Some research has studied the effects of stretching for 30 seconds on the amount that a muscle can produce immediately after. Some studies followed participants who had followed a stretching protocol in their preseason through their competitive season and measured their rate of injury compared to athletes who did not follow a stretching protocol.
Other studies looked at stretching post workout and perceived muscle soreness. In some studies, stretches were held for 60-90 seconds. In other studies, participants performed dynamic stretching, which is where a muscle or muscle group is put on stretch briefly as it moved through a range of motion.
Is anyone else dizzy yet? I know I am. While there have been a lot of studies on stretching, it is difficult to say what type of stretching is best for runners, and where within the realm of a workout that stretch belongs.
Here are some things we do know:
–Static stretching before a workout or event may decrease the amount of force that the muscle is able to produce, and may produce overall performance. (McHugh, 2010)
-Dynamic stretching may not have the same detrimental effects on performance that static stretching does. (Herda, 2008, Hugh, 2009) A dynamic stretch is when a muscle or muscle group is moved through its range of motion and the stretch is held very briefly (for less than a second).
-Participation in a regular flexibility program may help to decrease the rate of injury.
– Static stretching before a workout or event does not decrease the risk of injury. (Thacker 2004, Yeung 2005)
– Static stretching before or after a workout or event may not decrease the perceived amount of soreness that once may experience. (Herbert 2002)
– Prolonged stretching (i.e. 3 minutes or more) in cadavers and animal models will break down sarcomeres and result in tissue lengthening.
-Stretching may enhance recovery in an injured population. (Millaropoulos 2004, Page 2012)
With these thoughts on stretching, it should also noted that these principles apply to runners. Concepts surrounding stretching for activities such as dance or gymnastics are different.
So how does this apply to me?
Static stretching before a workout or event may not decrease your risk of injury, or improve your performance. Dynamic stretching before a workout or event may help your performance. Dynamic stretching after performing a warm up may help to decrease your risk of injury.
Stretching as part of a rehabilitation routine may help aid in your recovery from that injury. So if you are working with a physical therapist, or other professional who has prescribed a stretching routine for you, please continue with that routine. Most likely this professional has performed an examination of you, and made an assessment of your condition. Their decision to prescribe you with stretching is based on unique factor regarding you, your body type and your injury. The information provided in this post is best applicable to a general population.
What are some dynamic stretches that are good for runners?
Having adequate ankle mobility, knee extension and hip extension are critical to good running form. Good running form is efficient, and efficient form is associated with a decreased risk of injury.
Good news! Some warm up exercises mentioned in my previous post are also considered dynamic stretches:
Walking lunges: https://www.youtube.com/watch?v=ZYBl-_Cw7-Y
Walking knee to chest: https://www.youtube.com/watch?v=ryvj67TPyPA
Walking butt kicks: https://www.youtube.com/watch?v=fMOOt13Nuho
Leg swings are another good dynamic stretch for runners: https://www.youtube.com/watch?v=naW8u72lOzI
Bibliography:
Hebert, RD, Gabriel, M. Effects of stretching before and after exercising on muscle soreness and risk of injury: A systematic review. British Journal of Medicine. 2002: 325.
Herda,TJ, Cramer, JT, Ryan, ED, McHugh, MP, Stout, JR. Acute effects of Static versus Dynamic stretching on Isometric Peak Torque, Electromyography, and Mechanomyography of the Biceps Femoris Muscle. Journal of Strength and Conditioning Research. 2008: 22(3): 809-817
Hough, PA, Ross, EZ, Howatson, G. Effects of Dynamic and Static Stretching on Vertical Jump Performance and Electromyographic Activity. Journal of Strength and Conditioning Research. 2009: 23(2): 507-512
Malliaropoulos, N, Papalexandris, S, Papalada, A, Papacostas, E. The role of stretching in rehabilitation of hamstring injuries: 80 athletes follow-up. Medicine and Science in Sports and Exercise. 2004: 36(5): 756-759
McHugh, MP, Cosgrave, CH. To stretch or not to stretch: the role of stretching in injury prevention and performance. Scandinavian Journal of Medicine and Science in Sports. 2010: 20: 169-181
Page, P. Current Concepts in Muscle Stretching for Exercise and Rehabilitation. International Journal of Sports Physical Therapy. 2012: 7(1): 109- 119
Thacker, SB, Gilchrist, J, Stroup, DF, Kimsey, CD. The Impact of Stretching on Sports Injury Risk: A Systematic Review of the Literature. Medicine and Science in Sports and Exercise. 2004: 36(3): 371-378
Yeung, EW, Yeung SS, Interventions for preventing lower limb soft-tissue injuries in runners ( Review). The Cochrane Library. 2005: 3
Young, WB, Behm, DG. Effects of running, static stretching and practice jumps on explosive force production and jumper performance. The Journal of Sports Medicine and Physical Fitness. 2003: 43: 21-27