Power generation is largely achieved during training by which type of contraction?

• A. Eccentric contraction
• B. Isometric contraction
• C. Concentric contraction
• D. Plyometric contraction

Answer: (C)

Power is the rate at which work is done, and work is produced when a muscle shortens and moves a joint. A concentric contraction is when the muscle shortens while generating force, doing positive work as the limb moves quickly; this directly increases power, and higher shortening speeds boost power further. Isometric contractions produce force without any movement, so they generate little to no power. Eccentric contractions lengthen the muscle under tension and can generate large forces, but the movement is opposite to the force, which often results in negative or lower power. Plyometric training uses a rapid eccentric stretch followed by a quick concentric action to maximize power, but the immediate power output comes from the concentric phase.