Muscle fatigue is a reduction in the ability of a muscle to do the job it was intended to do, or to exert a force. It often occurs after athletic training or participation in sports. It can have a number of causes, not the least of which is simply overuse of the muscle. The buildup of lactic acid, which occurs after great physical exertion, has been blamed for muscle soreness for many years, but it is only partly at fault. Now it is thought that DOMS, or delayed-onset muscle soreness, is a cause. This is actually a mild form of rhabdomyolysis, which is the death of muscle fibers or proteins which then enter the bloodstream. When they enter the circulation, the kidneys must deal with the fallout, and if the condition is severe, it’s possible to go into kidney failure, because the severe form of rhabdomyolysis can be life-threatening. It’s always important for those who exercise to allow their muscles to rest after intense exertion, and to take a diet that is high enough in complex carbohydrates, minerals, and protein.

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