Flexibility is commonly defined as the range of motion around a joint. For each joint there is a degree of flexibility that is considered normal and optimum for daily functioning. Many activities, however including gymnastics, sprinting, dance and martial arts, require a greater degree of range of motion than is normal for everyday living.
Exercise manuals usually refer to four types of stretching: static, mobilization, proprioceptive Neuromuscular Facilitation or PNF, and ballistic.
In static stretches, a progressive mild stretch takes place in a set position. Mobilization stretching uses a full-range movement around the joint. The PNF technique, which often involves a partner, uses a specific technique to stimulate the muscles and tendons for increased-range work. Ballistic stretching, which incorporates mild bouncing in a static stretch position is useful for elastic strength warm-ups.
Static stretching is relatively safe and is easy to start with. It also makes an ideal cool-down after a workout. Mobilization stretching is the most functional. PNF and ballistic stretching are more advanced, with a higher risk of injury, and are not generally recommended without specialist assessment and instruction.
Benefits of flexibility training
While opinions differ on the benefits of improved flexibility, lack of flexibility is a significant factor in postural compensation, reduced freedom of movement, increased risk of muscle tension, and injury. Some people are naturally more flexible than others, influenced by factors such as gender, genetics, age and level of physical activity. People who are less active tend to be less flexible and sedentary persons tend to lose flexibility as they age.
The benefits of regular stretching include ease of movement and better postural alignment, the ability to offset age-related loss of flexibility, and a reduced risk of injury and tension.
Conflicting research on stretching may miss the essential relationship between strength and flexibility: muscles work in both agonistic and antagonistic relationships, that is, some muscles work together and some oppose each other.
In opposing groups, imbalance in one will affect the other. For example, tightness in the Erector spinae will inhibit the abdominal muscles ability for full-range contraction; and tight biceps will leave the triceps in a slightly elongated position.
In case of significant postural imbalance, some muscles will be tight and some weak. Tight muscles need stretching and weak muscles, strengthening. Many functional training experts agree that one of the best ways to stretch a tight muscle affected by postural imbalance is to strengthen the opposing muscle group.
Remember that adequate neuromuscular assessment is necessary to determine which stretch and strength exercises are necessary for each individual.
References: Anatomy for strength and fitness training by Mark Vella