What is the source of energy for muscle contraction?

Explanation

ATP (Adenosin Triphosphate) is the source of energy for muscle contraction. The head of each myosin molecule contains an enzyme called myosin ATPase.
In the presence of this enzyme along with `Ca^(2+)` then, and `Mg^(2+)` ions the ATP molecule breaks down into ADP and inorganic phosphate, thus releasing energy in the head of myosin.
`ATP rightarrow ADP+P_(i)+" Energy"`
Energy from ATP causes energised myosin to cross bridges and to bind with actin and in this way initiates muscle contraction.