This is the most common form of stretching people have heard of and also probably the most commonly used too. Static stretching is about gradually elongating the muscle and how static stretching is done is simply by holding a position to mild discomfort for roughly 10-30 seconds. Static stretching can be done usually twice a day, some do one session in the morning and another session in the afternoon, and most people usually do 2-3 repetitions for each muscle group.
Proprioceptive Neuromuscular Facilitation (PNF)
Many people recommend PNF over other forms of stretching because they find it to be more effective at increasing the flexibility of the muscle because of how it manipulates the body’s neural mechanisms. PNF combines passive and isometric forms of stretching to help achieve increases in flexibility. PNF is performed by first stretching the muscle with external force, using a partner, bodyweight, etc., and when the limit of the stretch is achieved hold that position for roughly 30 seconds, although the muscle should be contracted during this time, and when the muscle finally relaxes stretch it a little further again, and so on and so forth. Usually PNF is only performed once a day. An example of the technique would be to sit on the floor extend the leg at the knee and put a towel on the end of the foot and pull back on the foot until the stretch is achieved in the calve muscle and then contract the calve muscle and repeat as necessary.
One important thing to remember is this deals with passive flexibility. Movement dysfunctions can still happen because of altered firing patterns within the muscle and if that is the case more than likely soft tissue work such as SMR should be incorporated and specific warm ups should be done to help get the weak muscles firing correctly and loosen up the tight/overactive muscles from firing at the wrong times.