Following are the three types of stretching techniques that increase ROM and lengthen muscles and connective tissues:

• Static stretching (including passive static and dynamic static)

• Ballistic stretching

• Proprioceptive neuromuscular facilitation (PNF stretching).

1. Ballistic StretchingBallistic stretching is generally not used to increase muscle length. Ballistic stretching involves a rhythmic bobbing or bouncing motion that can invoke a stretch reflex that can actually cause a counter-contraction that opposes the desired outcome of achieving a stretch (remember those bouncy stretches from long-ago physical education classes?). 

This action can actually put the muscle at risk for injury. Muscle stretch reflexes are controlled by the muscle spindles located inside the muscle cells. These are involuntary responses propagated by the sensory nerves.When provoked, this action can result in a muscle contraction, causing increased muscle tension as opposed to muscle relaxation, the opposite of what a static stretch is designed to do.There is a time and place for ballistic stretching. If you are a track and field athlete and you run in races that involve the steeple chase or hurdles, you should practice ballistic stretches in specific ranges of motion that lend themselves to those activities. 

In these cases (and others), ballistic stretching would help you perform these activities safely and efficiently, but they would only be performed when the body temperature is elevated.Don’t confuse ballistic stretching with dynamic stretching

2. Dynamic static stretching is controlled and deliberate, whereas ballistic stretching is jerky and uninhibited. Dynamic static stretches are held for about 6 to 10 seconds. 

Although a little movement may occur and they may look like ballistic stretches, there is more control and not as much of a bounce. Most stretching exercises should be performed without bouncing or jerking, because these actions may injure connective tissues and stimulate the stretch reflex.

3. PNF Stretching Proprioceptive neuromuscular facilitation (PNF) stretching is a technique originally derived from rehabilitation settings such as physical therapy. Personal trainers often use this technique one on one with clients. PNF involves passively static stretching a muscle immediately after maximally contracting it against resistance.Research has found PNF stretching to be extremely effective at increasing passive ROM about a joint, but it is not always practical because it usually requires the assistance of a partner.The following cool-down stretches include both types of static stretches (passive and dynamic). 

Along the way, it is a good idea to perform stretches within the context of the workout, particularly upper body stretches and stretches specific to the body part you have just worked. This way, by the time you get to the cool down stretches, you can focus on full-body stretches that release tension from the major muscle groups.