UPSC CDS 1 2018 GK Paper

Accumulation of Lactic acid in the muscles of sprinters leads to cramp. After a strenuous exercise muscles experience lack of oxygen. In the absence or insufficiency of oxygen, muscle respire anaerobically thereby producing lactic acid. The accumulation of lactic acid causes cramps in muscles. Thus, Lactic acid is formed and accumulated in the muscle under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of O2.