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Warm-up and flexibility
Warm-up and flexibility

Normal Static Flexibility
The wealth of research on static flexibility measurements provides a general picture of what is normal static flexibility for most joints and populations. Normal static flexibility is the typical joint movement allowed between two extremes (Fig. 9.4): ankylosis and hypermobility (85,93). Ankylosis is pathological loss of ROM, while hypermobility is excessive ROM. Static flexibility is not a wholebody characteristic but, like fitness, is specific to joints and directions of movement (33,39). People may tend to have low static flexibility in one part of the body and normal or high flexibility in another. It is also clear that females have greater static flexibility than males (33), and some of these differences are related to anthropometric differences (13). Fitness professionals can access data on normal ranges of static flexibility for most joints from several professional sources (4–6,27). Several recent reviews of flexibility have been published (1,23,42, 51,64,59) and provide more information on static flexibility. It is unclear however, whether an “optimal” level of static flexibility for muscle groups or areas of the body exists. If this is the case, it is likely that different sports would require different optimal levels of static flexibility. Future research studies should be designed to focus on determining “normative” static ranges of motion at joints in athletes participating in specific sports, as well as documenting anomalies in athletes and active people who are outside of this normative range. It is too early to make a definitive statement, but it is possible that an athlete or active person whose muscles are too tight is more prone to muscle injuries and that one whose muscles are too loose is more prone to joint injuries as well as decreased performance in strength and power activities. Common deviations from normal static flexibility are present in many joint(s). Some people lose ROM from physical inactivity. People may also lose static flexibility from workplace or sportspecific positions and/or repetitive movements. For example, the repetitive motion in several sports with overhead throwing patterns (baseball, tennis, etc.) without specific stretching intervention (47) can result in glenohumeral internal rotation deficit (GIRD). Persistent wearing of high heels can decrease ankle dorsiflexion ROM (Fig. 9.5).

Warming-up and stretching for improved physical performance and prevention of sports-related injuries.

Competitive and recreational athletes typically perform warm-up and stretching activities to prepare for more strenuous exercise. These preliminary activities are used to enhance physical performance and to prevent sports-related injuries. Warm-up techniques are primarily used to increase body temperature and are classified in 3 major categories: (a) passive warm-up - increases temperature by some external means; (b) general warm-up - increases temperature by nonspecific body movements; and © specific warm-up - increases temperature using similar body parts that will be used in the subsequent, more strenuous activity. The best of these appears to be specific warm-up because this method provides a rehearsal of the activity or event. The intensity and duration of warm-up must be individualised according to the athlete's physical capabilities and in consideration of environmental factors which may alter the temperature response. The majority of the benefits of warm-up are related to temperature-dependent physiological processes. An elevation in body temperature produces an increase in the dissociation of oxygen from haemoglobin and myoglobin, a lowering of the activation energy rates of metabolic chemical reactions, an increase in muscle blood flow, a reduction in muscle viscosity, an increase in the sensitivity of nerve receptors, and an increase in the speed of nervous impulses. Warm-up also appears to reduce the incidence and likelihood of sports-related musculoskeletal injuries. Improving flexibility through stretching is another important preparatory activity that has been advocated to improve physical performance. Maintaining good flexibility also aids in the prevention of injuries to the musculoskeletal system. Flexibility is defined as the range of motion possible around a specific joint or a series of articulations and is usually classified as either static or dynamic. Static flexibility refers to the degree to which a joint can be passively moved to the end-points in the range of motion. Dynamic flexibility refers to the degree which a joint can be moved as a result of a muscle contraction and may therefore not be a good indicator of stiffness or looseness of a joint. There are 3 basic categories of stretching techniques: (a) ballistic--which makes use of repetitive bouncing movements; (b) static--which stretches the muscle to the point of slight muscle discomfort and is held for an extended period; and © proprioceptive neuromuscular facilitation - which uses alternating contractions and stretching of the muscles. Each of these stretching methods is based on the neurophysiological phenomenon involving the stretch reflex.(ABSTRACT TRUNCATED AT 400 WORDS).

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