The Truths About Stretching

Dr. Chelsea Moehlenbrock Author

Artistic athletes require much more flexibility than the average person. This flexibility does not come easy to everyone and there are some methods of stretching that can be dangerous for young growing bodies.

Many people think that stretching is simply lengthening the muscle fibers so that they are longer. However, our overall flexibility is impacted by more than just muscles. The tendons, ligaments, connective tissue, and neural input (the signals our brain sends through our nerves to the joint and muscle) affect how much range we have access to in our bodies. In addition to this, factors such as age, sex, and genetics also play a major role.

As more research develops on flexibility and stretching, we are gaining knowledge that stretching doesn’t work how we used to think it did. Here are some newer findings with regards to stretching:

1) Stretching has not been shown to reduce risk of injury. It’s a common belief that stretching helps prevent injuries. However, research has shown the same injury rates in people that stretch and those that don’t stretch. Here’s an interesting study though: the Australian Ballet stopped having their dancers do calf stretches and instead had them do more calf raises, which would build more strength. This did show a significant decrease in injury rates. This supports the concept that dancers need more strength and conditioning to prevent injuries, not just hoping that stretching is the answer.

2) Stretching does not prevent soreness when done before or after activity. Studies have looked at if stretching before, after, or before and after exercise can reduce muscle soreness. Evidence shows that stretching has a near-zero effect on muscle soreness. One article points out that the belief that stretching reduces soreness comes from a mistaken belief in the 1960s and 1970s that muscle soreness was the result of muscle spasms. We know now that is not the case. More modern theories explain that muscle soreness is the result of the excessive lengthening of the sarcomeres (the units within a muscle that work together to create contractions). However, there is weak evidence that once muscle soreness occurs, stretching can temporarily reduce that soreness. This may be due to a neuro-dampening effect, meaning the tissues become less sensitive to certain stimuli afterwards.

3) Stretching does not lengthen muscles or tendons. The improved range is most likely due to an increase in comfort with that position due to decreased sensitivity of our nervous system.

Our nervous system plays a major role in our flexibility because it is the driving input to create muscle tension and is there to protect our tissues from getting injured. Our nervous system’s sensitivity to end ranges is what puts the brakes on and limits how far a joint can go. When people are under anesthesia for surgeries and have no neural input to their joints, their bodies are much more flexible than they are when they are conscious. Someone who cannot typically touch their toes can easily fold in half under anesthesia. We have receptors and reflexes that need neural input from our central nervous system to protect our muscles and tendons from getting pulled too quickly into the end of our range of motion. That’s why typically it takes at least 30 seconds of being in a stretch for the muscles to feel like they are relaxing into that stretch. It’s those receptors realizing that they don’t need to keep the muscle tense to protect it.

So what is the best way to get more flexible? There’s not a clear, simple answer to this since everyone’s body is different. Typically it takes at least six weeks to start seeing changes in flexibility when someone is consistently stretching three to fives times per week. Our tissues take time to adapt to the new stimulus. Not one method seems to be clearly better than another when it comes to improving flexibility. However, some methods are safer than others for young growing dancers. Stay tuned for next month’s blog which will cover six different types of stretching and explain which are the safest for young dancers.

Resources:

Ben M, Harvey LA. Regular stretch does not increase muscle extensibility: a randomized controlled trial. Scand J Med Sci Sports. 2010 Feb;20(1):136-44. doi: 10.1111/j.1600-0838.2009.00926.x. Epub 2009 May 22. PMID: 19497032.

Herbert RD, de Noronha M, Kamper SJ. Stretching to prevent or reduce muscle soreness after exercise. Cochrane Database Syst Rev. 2011 Jul 6;(7):CD004577. doi: 10.1002/14651858.CD004577.pub3. PMID: 21735398.

Konrad A, Tilp M. Increased range of motion after static stretching is not due to changes in muscle and tendon structures. Clin Biomech (Bristol, Avon). 2014 Jun;29(6):636-42. doi: 10.1016/j.clinbiomech.2014.04.013. Epub 2014 May 10. PMID: 24856792.

McHugh MP, Cosgrave CH. To stretch or not to stretch: the role of stretching in injury prevention and performance. Scand J Med Sci Sports. 2010 Apr;20(2):169-81. doi: 10.1111/j.1600-0838.2009.01058.x. Epub 2009 Dec 18. PMID: 20030776.

Reisman S, Walsh LD, Proske U. Warm-up stretches reduce sensations of stiffness and soreness after eccentric exercise. Med Sci Sports Exerc. 2005 Jun;37(6):929-36. PMID: 15947716.

Small K, Mc Naughton L, Matthews M. 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. 2008;16(3):213-31. doi: 10.1080/15438620802310784. PMID: 18785063.

Thacker SB, Gilchrist J, Stroup DF, Kimsey CD Jr. The impact of stretching on sports injury risk: a systematic review of the literature. Med Sci Sports Exerc. 2004 Mar;36(3):371-8. doi: 10.1249/01.mss.0000117134.83018.f7. PMID: 15076777.

Weppler CH, Magnusson SP. Increasing muscle extensibility: a matter of increasing length or modifying sensation? Phys Ther. 2010 Mar;90(3):438-49. doi: 10.2522/ptj.20090012. Epub 2010 Jan 14. PMID: 20075147.