Stretching Facts And Fallacies Of Fitness Part 2
Flexibility is an integral part of all training. No movement is possible without a certain degree of flexibility. Movement constantly restricted to a particular range produces a specific range of movement for the relevant joint. Increase in training range results in increased flexibility. In other words, the normal range of movement regularly used in normal training sessions will produce its own characteristic range of flexibility.
One of the fundamental principles of physiotherapeutic PNF (proprioceptive neuromuscular facilitation) is that appropriate, effective physical conditioning depends on developing an optimal balance between mobility and stability . Excessive flexibility can result in reduction of stability; inadequate flexibility often characterises a state of high stability, but low mobility. A fully functional range of static and dynamic flexibility is what is necessary for all physical activity, where functionality depends on the amount of useful strength which may be produced from beginning to end of range.
Extract from Facts and Fallacies of Fitness by Dr Mel Siff. skorea.