Static flexibility is generally not associated with dynamic production of strength and constitutes only the one aspect of functionality. Unfortunately, most articles and books stress the safety of static stretching, thereby deterring instructors and coaches from using other more dynamic types of stretching. Exercise proficiency and safety is determined by static and dynamic flexibility, but, more specifically the ability of the soft tissues associated with a joint to withstand deformation and protect the joint, to absorb shock loading, to store elastic energy for subsequent use in explosive movements, and to exhibit static and dynamic strength over an adequate range of movement.
Research has corroborated the PNF approach that overall flexibility is developed most effectively by full range strength training, some of which may even include strong recruitment of the stretch reflex (Knott M & Voss D Proprioceptive Neuromuscular Facilitation 1968). Furthermore, there is no real need to prescribe separate stretching exercises or sessions, since logically structured training should take every joint progressively through its full range of static and dynamic movement. In other words, every movement should be performed to enhance flexibility, strength, speed, local muscular endurance and skill, so that separate stretching sessions then become largely redundant.
For example, to improve flexibility of a particular joint, one could warmup first by performing the chosen exercise at low intensity and low speed for a high number of repetitions over a gently increasing range before gradually increasing the range of movement and the resistance. In doing so, it is important to remember that no joint or muscle is intended strictly for operation in one direction, so that it is essential to follow three dimensional patterns of movement which are characteristic of all normal movement.
Although static stretching is inadequate to develop overall functional flexibility to meet the demands of all activities, there is nothing wrong in designing separate flexibility sessions which focus on static and dynamic stretching. It is obviously more efficient to incorporate flexibility training into every exercise, not merely because of the saving in time, but also because flexibility is specific to the joint and type of movement (for details, see Siff MC, Supertraining, 2000).
Extract from Facts and Fallacies of Fitness by Dr Mel Siff