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Muscular System

What type of fermentation causes muscles to get sore when overworked?


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September 30, 2009 11:21PM

People used to think that a build-up of lactic acid was the cause of muscle soreness. That is not true. Lactic acid has nothing to do with it, therefore the fermentation process the body uses to get the lactic acid into the muscles is also not true. Muscle soreness is caused by the damage done to the muscle fibers. Muscle biopsies taken on the day after hard exercise show bleeding and disruption of the z-band filaments that hold muscle tissue together as they slide over each other during a contration. Scientists can tell how much muscle damage has occurred by measuring blood levels of a muscle enzyme called CPK. CPK is a normally found in muscles and is released into the bloodstream when muscles are damaged. Those exercisers who have the highest post-exercise blood levels of CPK often have the most soreness. Many people think that cooling down by exercising at a slow pace after exercising more vigorously, helps to prevent muscle soreness. It doesn't, cooling down speeds up removal of lactic acid from muscles, but a build-up of lactic acid does not cause muscle soreness, so cooling down will not prevent it. Stretching does not help either, since post-exercise soreness is not due to contracted muscle fibers.