What is the purpose of an eccentric muscle contraction?

An eccentric muscle contraction occurs when a muscle lengthens while producing force. This type of contraction is particularly effective in decelerating movements, allowing the body to control its motions as it returns to a resting position or responds to a change in direction. During activities such as descending stairs or lowering weights, eccentric contractions help stabilize joints and prevent injury by controlling the speed at which the body moves. In this context, the muscle is actively engaged as it lengthens, helping to manage the forces acting on the body.

Other types of contractions, such as concentric contractions, are responsible for accelerating body parts as they shorten during movement. Isometric contractions maintain muscle length but do not involve any change in joint angle. While eccentric contractions can contribute to increased muscle strength over time, especially when incorporated into a well-rounded training program, their primary function in the moment is to decelerate and control movement.