Final answer:
If the concentric phase of a plyometric exercise doesn't use all the stored elastic energy from the eccentric phase, the remaining energy is dissipated as heat within the muscles and surrounding tissues.
Step-by-step explanation:
During a plyometric exercise, the concentric phase involves the contraction of muscles to produce explosive movements. The eccentric phase, on the other hand, involves the lengthening of muscles while they store elastic energy.
If the concentric phase of a plyometric exercise doesn't use all the stored elastic energy from the eccentric phase, the remaining energy is dissipated as heat within the muscles and surrounding tissues. This is because the muscles cannot efficiently convert all the stored elastic energy into mechanical work. Therefore, the excess energy is lost in the form of heat.