Eccentric activation is associated with internal torque when the joint moves how?

Eccentric activation is associated with internal torque when the joint moves how?

• A. In the same direction as the muscle's action
• B. Opposite the direction of the muscle's action
• C. Without any muscle activity
• D. Only during non-weightbearing

Answer: (B)

Eccentric activation involves producing force while the muscle lengthens, and the joint motion is in the opposite direction to what the muscle would cause if it were shortening. In this mode, the muscle’s internal torque acts to oppose the actual movement, letting external forces (like gravity or momentum) drive the joint while the muscle controls and slows the motion. For example, when you lower a weight, the elbow extensors are activated and lengthen; their torque would tend to flex the elbow, which is opposite to the observed elbow extension. This resisting, opposite-torque role is what characterizes eccentric activation.

Eccentric activation involves producing force while the muscle lengthens, and the joint motion is in the opposite direction to what the muscle would cause if it were shortening. In this mode, the muscle’s internal torque acts to oppose the actual movement, letting external forces (like gravity or momentum) drive the joint while the muscle controls and slows the motion. For example, when you lower a weight, the elbow extensors are activated and lengthen; their torque would tend to flex the elbow, which is opposite to the observed elbow extension. This resisting, opposite-torque role is what characterizes eccentric activation.