Unloading elastic energy adds to tension in concentric muscle contraction. Which component is this addition associated with?

• A. Eccentric component
• B. Isometric component
• C. Concentric component
• D. Transitional component

Answer: (C)

When a muscle shortens, the energy stored in its elastic elements (like tendons) is released and adds to the force produced by the muscle fibers themselves. This extra contribution happens during concentric contraction, when the muscle is actively shortening. So the elastic recoil enhances tension specifically in the concentric phase, making it the component that this addition is associated with. In contrast, energy is absorbed (not added) during eccentric contraction, there is no length change in isometric contraction, and “transitional” isn’t a standard category in this framework.