In the case of a strength/power athlete such as a javelin thrower or shot-putter, what is stored in the muscle that enables these athletes to meet the immediate energy demands to complete a throw?

adenosine triphosphate (ATP)

creatine phosphate (CP)

ATP supplies the energy for muscle contraction to take place. In addition to its direct role in the cross-bridge cycle, ATP also provides the energy for the active-transport Na+/K + and Ca2 + pumps. Muscle contraction does not occur without sufficient amounts of ATP. Phosphocreatine, also known as creatine phosphate (CP) or PCr (Pcr), is a phosphorylated creatine molecule that serves as a rapidly mobilizable reserve of high-energy phosphates in skeletal muscle and the brain to recycle adenosine tri phosphate; which is the energy currency of the cell.