By Justen Hinerman PT, DPT | Therapydia Pearlridge
If you stretch a muscle it will get longer, making it more “flexible”, right? This is how we assume stretching works, but it turns out that might not be true.
Generally stretching is accomplished by getting into some extended position that causes discomfort for approx 30 seconds or some other arbitrary number. The thought used to be is we were making ourselves more flexible, (actually making the muscle longer). We were told being flexible had the following benefits: decrease risk for injury, improved athletic performance, and could help reduce soreness we had from a previous workout. However as more studies come out over the past decade we are learning the previously mentioned items may just not be true.
What is Actually Happening When We Stretch?
The stretching of a muscle fiber begins with the sarcomere, the basic unit of contraction in the muscle fiber. As it stretches, this area of overlap decreases, allowing the muscle fiber to elongate. Once the muscle fiber is at its maximum resting length, additional stretching places force on the surrounding connective tissue. When the muscle is stretched, so is the muscle spindle. The muscle spindle records the change in length (and how fast) and sends signals to the spine which convey this information. This triggers the stretch reflex which attempts to resist the change in muscle length by causing the stretched muscle to contract. The more sudden the change in muscle length, the stronger the muscle contractions will be. This basic function of the muscle spindle helps to maintain muscle tone and to protect the body from injury. The reason for holding a stretch for a prolonged period of time is that as you hold the muscle in a stretched position, the muscle spindle habituates and reduces its signaling. This will gradually over time allow you to train your stretch receptors to allow greater lengthening of the muscles. Our ability to be more flexible occurs from neuro adaptations, rather than our muscles getting “longer.”
Athletic Performance & Injury Reduction
Static stretching prior to activity can result in a loss of contractile power/strength for up to 30 minutes. This can cause temporary weakness in the muscle, loss of the ability to contract maximally, and decrease the ability of the muscle receptor to engage the “stretch reflex” (safety mechanism) which can increase risk of injury. Think about all the sports/activities in which you would need to be your strongest and produce high power output for extended periods of time.
Stretching doesn’t provide any lasting pain relief. Muscle soreness is generally the result of a previous day’s training session. This soreness is caused by the muscle damage induced during that particular training session. No matter how much you stretch, this will not help repair the muscle tissue from your previous workouts.
So Should We Stretch?
If your upcoming workout is focused on strength or if your sport requires you to be explosive, try skipping your typical static stretches and instead replace those with a dynamic warm-up that mimics similar movements you will be completing.
If you enjoy stretching on your off days, try performing a yoga routine instead. Not only will this allow you to stretch in various positions, but you will also be working important things like stability, mobility and core strength.
For sore muscles (DOMS), stop stretching. Active recovery such as walking, hiking, or some light cardio will help provide a relief from soreness without damaging more muscle fibers.
To build flexibility in the long term vs short term static stretching, try adding eccentric exercises (an active muscle contraction while lengthening) to your workout.
If you are not sure where to start feel free to give us a call, we are here to help! For some examples of how to perform dynamic stretches, take a look at our other blog post CrossFit Dynamic Warm-Up Moves.
- Smith, Craig A. “The warm-up procedure: to stretch or not to stretch. A brief review.” Journal of Orthopaedic & Sports Physical Therapy 19.1 (1994): 12-17.