I have read a couple of interesting articles on pre-activity stretching over the past year or so, & would like to hear your opinion on the subject on how to increase your vertical jump. The articles I am referring to quoted a number of studies from the US and Australian military which demonstrated a decrease in injury rates when static stretching was NOT performed before physical activity. There was not a clear explanation of these results, but the ‘theory’ was that static stretching introduced a sufficient degree of ‘slack’ in the muscles, ligaments and tendons to increase the risk of injury. This ‘slack’ was also said to reduce the athletes’ power in the physical activities that followed the static stretching. A group that performed a regular static stretching program at a time OTHER than immediately before physical activity had the lowest injury rates among the test groups. What are your thoughts on this issue?!
Ok, first off there is some credible research behind the idea that static stretching prior to training will decrease muscle strength temporarily. But the fact is if you have a chronically short/tight muscle, it will inhibit the antagonist as well. So if your chest is tight, for example, you will have neuromuscular inhibition of the scapular retractors to some degree. The pectoralis major is an internal rotator of the arm. Tightness of this muscle can inhibit the external arm rotators (rotator cuff). Inhibition of the rotator cuff can decrease stability of the shoulder and increase injury potential. So, generally this research may be correct, but the application of this theory is not clearly defined. I fully support the idea of stretching muscles that tend to be tight in certain sports. In volleyball, for example, generally players will have tight hamstrings, quads, hip rotators, chest, lats, and abs. These tight muscles will alter proper joint mechanics and must therefore be stretched prior to playing to decrease joint and soft tissue stress. A good question to ask the researchers of the studies you mentioned would be, “Did you identify specific muscles that needed to be stretched on an individual basis, or did you prescribe a general stretching routine to everyone?”
For another question about increasing to vertical jump you can see this article: Exercises to increase vertical jump