Power, in physics, is the "rate at which work is performed," i.e. work is the "product of force and distance" (Work = Force x Distance).  What this usually translates to is the ability to exert maximum muscular contraction instantly in an explosive burst of movement, ie. the ability of a muscular unit, or combination of muscular units, to apply maximum force in minimum time. The two components of power are strength and speed, as with power exercises. (e.g. jumping or a sprint start, snatch, clean and jerk, etc.)  Power is a vital component of motor fitness, and is applicable especially to a myriad of athletic activities, and therefore it should not be neglected. Despite the importance of power for athletics and function, the ability to produce powerful muscle contractions decreases with age, more so than other components, such as cardiorespiratory endurance. This decline also appears despite persistent training and otherwise good health.