Are You Stretching or Warming Up?
Tue Mar 19, 2013 by Phil Cheetham
Being a gymnastics coach; specifically Trampoline and Tumbling, a sub-discipline of gymnastics; I receive a technical magazine called “Technique” from USA Gymnastics. In the November/December 2010 issue there was an excellent article called “Are You Stretching or Warming Up?” by Megan Gearhart. Megan is a physical therapist and a former World Tumbling Champion, and I think she has written one of the best and clearest articles on stretching that I have read. Here is my summary of the important points, plus some of my own “spin”.
The Stretch Reflex: Whenever a muscle is stretched beyond its normal resting length the stretch reflex will occur. Sensors in the muscle called “muscle spindles” signal the spinal cord that the muscle is being stretched and the spinal cord sends back a signal to the muscle telling it to contract. This is done in order to protect the muscle and joint from possible injury. It doesn’t matter how fast you stretch, the mere action of stretching will invoke the stretch reflex. The faster or more ballistic the stretch the more intense the invoked muscle contraction will be. The standard example of this is the knee jerk when the doctor hits you on the patella tendon. If you stretch and hold the stretch for 10 or more seconds the muscle spindle gradually becomes accustomed to the new length and reduces its signaling to the spinal cord, allowing the muscle to relax slightly and also elongate more.
There are five basic types of stretching.
Static: The muscle is taken to a point of mild stretch and held there for 15 to 30 seconds. The muscle is then relaxed and the action is repeated, typically 2 to 4 times. Static stretching has been found to increase range of motion but does not increase core temperature.
Passive: Similar to static stretching but with a partner who is applying the stretch slowly and holding it for 15 to 30 seconds. As with static stretching, passive stretching has been found to increase range of motion but does not increase core temperature. With this method the partner must be very careful not to over-stretch the athlete and maybe cause injury.
Dynamic: Involves active motions that gradually increase in speed and range of motion. Good examples include arm circles; leg swinging and rapid knee lifts. Dynamic stretch increases range of motion but also increases core temperature and helps the muscles warm up.
Ballistic: Involves bouncing the muscle past its normal range of motion. Since this aggressively invokes the stretch reflex the muscle contracts to fight against the bouncing and this can cause injury to the muscle.
PNF: Proprioceptive Neuromuscular Facilitation also known as contract-relax stretching. This is performed with a partner, so as in passive stretching, the partner must be careful in properly applying the pressure. The partner slowly pushes the athlete to the stretched position (10 to 15 seconds). Then the athlete contracts and pushes back against the partner (7 to 15 seconds). Finally the athlete relaxes (2 to 3 seconds) and the partner pushes the athlete further into the stretch (another 10 to 15 seconds). This sequence is typically repeated 3 or 4 times. PNF is very effective for gains in range of motion.
Warm up versus Stretching
A decision must be made as to what is the goal of the stretching method. Are you wishing to increase range of motion or warm up for activity?
Dynamic stretching has been found to improve performance in high intensity activities, whereas static stretching immediately before jumping activities has been found to inhibit performance, for as long as two hours. Also, of all the methods mentioned so far, the only method that increases core temperature is dynamic stretching. On the other hand research has shown that both static and PNF stretching increase flexibility better than dynamic stretching. Ballistic stretching is not recommended since it tends to cause muscle soreness and even injury.
The bottom line is that dynamic stretching is great for warm up but not so great for large gains in range of motion. Static and PNF stretching are great for increasing range of motion but should be done after training so as not to hinder power and speed during training. If you insist on stretching at the beginning of the work out then at least warm up first, don’t use static or dynamic stretching on cold muscles as it less effective and could cause injury.
For the complete text of Megan’s article, the USA Gymnastics website has an awesome online magazine archive with all the back issues of Technique.
Megan Gearhart. Are You Stretching or Warming Up? Technique (Magazine). USA Gymnastics. November/December 2011.