WHEN there is a build-up of a waste product called lactic acid in your muscles, you get cramps. When a muscle works harder than usual (for example, you go for a run for the first time in months) it starts to break down its stored food without using any oxygen. This process produces the lactic acid, and a build-up of the lactic acid makes your muscles feel tired and sore.
WHEN there is a build-up of a waste product called lactic acid in your muscles, you get cramps. When a muscle works harder than usual (for example, you go for a run for the first time in months) it starts to break down its stored food without using any oxygen. This process produces the lactic acid, and a build-up of the lactic acid makes your muscles feel tired and sore.
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