Don't overestimate the power of the force

Muscular power depends on force-velocity, activation, and deactivation characteristics, all of which adapt to training. Resistance training programs intended to improve power have produced mixed results. We used previously reported data from heavy and explosive training programs [1,2] to modify muscle-tendon model parameters and evaluated power during cyclic contractions. Heavy training greatly increased force but also increased activation and deactivation time. Explosive training produced smaller improvements in strength and reduced activation and deactivation time. Both programs led to similar increases in maximum power but with different power-frequency relationships. Heavy training produced power at lower frequencies typical of swimming and speedskating, whereas explosive training produced power at higher frequencies typical of sprint running and cycling, and balance recover. These modeling results demonstrate the importance of activation and deactivation during cyclical contractions, particularly at higher frequencies.