140 Chapter 7: Training for Mobility perform requires an extensive amount of mobility and/or flexibility in order to be successful (e.g., gymnastics, cheerleading). In total, there are four types of stretches: static, ballistic, dynamic (aka mobility drills), and proprioceptive neuromuscular facilitation (PNF). • Static stretching. This type of active stretching uses a slow and constant stretch with the end position being held for at least 30 seconds. If done properly, static stretching will facilitate a central nervous system response which reduces muscle tension thereby allowing the muscle to lengthen. This reduction in muscle tension, although effective for improving flexibility and range of motion, is also associated with decreased force production, speed and reaction time. As a result, static stretching is best performed after a training session and not before. • Ballistic stretching. This type of active stretching uses bouncing type movements to an unheld end position. Because the muscle is stretched rapidly, the muscle spindle, which is located in the muscle belly, is activated which causes the muscle to contract instead of relax. This autonomic reflex is called the stretch reflex, which is counterproductive to the purpose of stretching and increases the risk of injury. As a result, ballistic stretching is generally not recommended. Figure 7.5 shows the location of the muscle spindle within the muscle. Figure 7.5. Muscle Spindle vs. Golgi Tendon Organ • Dynamic stretching. This type of active stretching uses sport-specific movements to prepare the muscles and connective tissue for the physical activity to follow. Dynamic stretching differs from ballistic stretching in that it uses slow and controlled movements instead of bouncing or jerky movements. Unlike static stretching, dynamic stretching is best performed before a training session as it helps to improve range of motion by raising body temperature which in turn increases the plasticity of the muscles and connective tissue. Examples of some dynamic stretches include walking toe touches, arm circles, walking knee hugs, side shuffles and backpedaling.
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