Performing a Chin-Up Is Usually Particularly Difficult at the Very

Multiple Choice

Performing a chin-up is usually particularly difficult at the very end of the exercise because

A) when the muscle is fully contracted, it is exerting a maximum amount of force.
B) there is so much overlap between actin and myosin in the sarcomeres.
C) of psychological fatigue that is a metabolic by-product of the exertion.
D) of the necessary switch from fast- to slow-twitch fibers.
E) the sarcomeres cannot shorten beyond their resting length.