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.

Question

Quizplus · Accepted Answer

The difficulty in performing a chin-up at the very end of the exercise is due to the significant overlap between actin and myosin in the sarcomeres. When the muscle is fully contracted, this overlap reduces the ability of the muscle fibers to generate force effectively.

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