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Abstract
It is defined as chronic disorders these are gradually developed over a period of time as result of mild or continuous repetitive stress to bone and muscular structures, this stress causes damage to these tissues without adequate recovery time (Verkhoshansky 1999).
It is based on the idea that tissues adapt to the stresses placed on them over time. These stresses include shear, tension, compression, impingement, vibration and contraction. Mechanical fatigue within tendons, ligaments, bones, neural tissues and other soft tissues (muscles &bursae) results in characteristic changes depending on their individual properties. This fatigue leads to adaptations of these tissues. As the tissues attempt to adapt to the demands placed on them, they can incur (cause or create) injury unless they have appropriate time to heal. The rate of injury simply exceeds the rate of adaptation and healing in the tissue (Barr et al., 2004).
Barr et al., (2004) suggest that chemical mediators are involved in initiation and propagation of overuse injuries. The development of muscular pain originates from the nearly continuous activation of low threshold motor units that occurs in muscles performing continuous or slow, repetitive tasks, causing depletion of adenosine triphosphate (ATP) in those fibers. With insufficient ATP, sacroplasmic reuptake of ca ++ could be reduced, resulting in high concentrations in the cytosol, allowing ca++ dependent activation of phospholipase, the generation of free radicals, and damage to the muscle fibers involved. The theory has a rational physiologic basis, but it remains to be proven. This is common in runners, equestrian athletes, ballet dancers, martial artists, workers, bicyclists, golfers, etc. This list dramatizes the point that at least the perception exists that many common ailments are associated with repetitive motion.