What muscle contraction occurs in the biceps brachii during upward phase of bicep curl?

During the upward phase of a bicep curl, the biceps brachii muscle undergoes concentric contraction. Concentric contraction refers to the shortening of a muscle while generating force, resulting in joint movement. In this case, the biceps brachii contracts, pulling the forearm and hand upward, bringing the weight towards the shoulder. The triceps brachii, the muscle on the back of the upper arm, undergoes eccentric contraction during this phase, lengthening to allow for the bicep curl movement.