Question

When your biceps brachii (upper arm) muscle contracts, ultimately and most directly, what is producing the movement? When your biceps brachii (upper arm) muscle contracts, ultimately and most directly, what is producing the movement? Your biceps brachii shortens. Your brain tells your muscle to contract. Proteins within the cells of the biceps brachii slide past each other lengthwise, shortening the muscle. You move your arm?

Answer 1

The correct answer is: Proteins within the cells of the biceps brachii slide past each other lengthwise, shortening the muscle.

The contraction of a muscle fiber occurs as the sarcomeres, linearly arranged within myofibrils, shorten as myosin heads pull on the actin filaments.