Final answer:
The kind of muscular contraction where a muscle shortens to produce force and move a load is a concentric contraction. This occurs, for example, when lifting a weight in a bicep curl, as the biceps muscle shortens, and the elbow angle decreases.
Step-by-step explanation:
The muscular contraction in which the muscle shortens to produce force and accelerate movement is called a concentric contraction. In this type of contraction, the muscle fibers shorten, and this shortening generates the movement of a load. For example, when you perform a bicep curl, the biceps brachii muscle undergoes a concentric contraction, pulling the forearm up towards the shoulder and decreasing the angle at the elbow joint, as the hand weight is lifted with increasing muscle tension.
An eccentric contraction differs from a concentric contraction in that the muscle lengthens while maintaining tension, which helps control the movement of a load as it returns to an initial position. If you were slowly lowering the hand weight in the bicep curl example, that would be an eccentric contraction.