Multiple stretching techniques have been researched with results showing they can be beneficial in improving ROM. Regardless of the specific technique or specific mode used, each technique can be performed using two basic modes: active or passive. Active stretching, also called unassisted stretching, suggests that the actual stretch is done individually without an external stimulus.Passive stretching, or assisted stretching is when a partner or trainer is used as the stimulus in the stretching exercise. Both modes are effective and can be applied to each of the techniques mentioned below.
The most commonly prescribed and most commonly used technique for improving flexibility is the static stretch. A static stretch involves slow, gradual and controlled movements. The muscle group is stretched toward the end of the joint ROM until the point of mild discomfort is reached. Once that point is reached, the stretch is held in a “static” position for 30 to 90 seconds. After the prescribed time, the stretch can be repeated. Common ways in which static stretching is applied would be in Yoga routines or stretching after a workout or athletic event.
Some of the major advantages for static stretching is that it is generally considered safe (see Stretches to Avoid), it is simple to perform and effective at increasing ROM. The only major disadvantage comes from when it is done too much which can reduce strength and may make joints unstable. Of course this could apply to any of the techniques.
Ballistic stretching involves forceful bouncing or ball-like movements that quickly exaggerate the joint ROM without holding the position for any particular duration. This type of stretching involves dynamic movements like those done by athletes during sports events. In that regard, ballistic stretching is seen as being very specific to and beneficial for athletes. However, one criticism of ballistic stretching is that because of the short duration of the stretch, and ballistic movements that can be forceful, the muscular contraction from the stretch reflex may cause muscle soreness or even injury. For that reason, many athletic coaches feel ballistic stretching is unsafe. Also, many researchers feel it is less effective at improving ROM. Nonetheless, the ACSM still recommends ballistic as one method to effectively increase flexibility.
Ballistic stretching is a form of dynamic stretching. However, when referring to dynamic stretching routines, most fitness professionals are referring to dynamic movements that don’t involve forceful bouncing motions. Instead, dynamic stretching, in this context, suggests performing exaggerated sports movements in a slower, more controlled manner. For example, a sprinter may use several exaggerated stride lengths before a race to improve hip ROM.
An advantage of dynamic stretching is that it will target and improve dynamic flexibility which in turn may improve performance. A disadvantage comes from the type of movements which often require good balance and coordination. So, learning correct form and being able to perform dynamic stretches may take a little time to learn or may not be applicable to certain populations.
Proprioceptive Neuromuscular Facilitation (PNF) Stretching
This type of exercise usually involves a partner. The partner will passively stretch the muscle, immediately followed by an isometric muscle contraction against resistance. This contraction is then followed by another passive stretch. This type of stretch is also named contract-relax stretch because of the sequence of movements involved. Other types of PNF stretching involve contract-relax-antagonist contrac- tion, also describing the sequence of movements involved but adding an additional step.
As the name of the technique implies, PNF stretching emphasizes the natural interaction of the proprioceptors with the muscles to increase the ROM during the stretch. Remember that during the stretch, the muscle spindles cause two things to happen, the stretch reflex and reciprocal inhibition (the antagonist muscle to relax). After 5 seconds, the GTO’s then override the muscle spindle’s signals causing autogenic inhibition. Because the muscle is relaxed, it can more easily be stretched. In other words, the stretch either uses the activity of the antagonist muscle to get the target muscle to relax or the target muscle itself to relax as a result of the contraction.
While many experts feel that PNF stretching is the most effective technique, studies that compare static and PNF stretching are inconclusive. Regardless, it does appear to be very effective at increasing static flexibility. Some disadvantages to PNF is that it generally requires a knowledgeable partner, it’s somewhat complicated, and can cause some soreness from the contractions.