(i) Energy released due to breakdown of ATP molecule is used up in the contraction of muscle.
(ii) This breaking down of ATP takes place in the presence of myosin ATPase.
(iii) There is another high energy compound called creatinine phosphate (CP), present in the muscle.
(iv) This creatinine phosphate maintains the regular supply of ATP. Creatinine phosphate reacts with ADP to give rise to ATP and creatinine.
ADP + CP \(\rightarrow\) ATP + Creatinine
(v) When the contraction is completed creatinine is again reconverted into creatinine phosphate by reacting with ATP to produce creatine phosphate.
