In an isometric contraction, how can the muscle stay the same length when the muscle is contracting? a. Elastic elements of the muscle stretch in response to the contraction of the muscle, so that the muscle stays the same size despite shortening sarcomeres. b. The myosin heads detach from actin when they reach the desired length. c. Calcium stops entering the sarcoplasm when the desired length is reached. d. The muscle is not able to generate more (or the same amount) force than the load, preventing shortening of the muscle.

Option-A

Explanation:

The contraction of the muscle depends on various factors like the elastic filaments present on the tendon which are arranged parallel and the myofilaments. The sarcomere is the functional unit of muscle fiber which when contracts shortens.

There is a type of muscle contraction in which the sarcomere shortens but the length of the muscle remains the same as in the muscle of hands called an isometric contraction.

During an isometric contraction, the elastic component of the elastic tissue does not shorten that is limbs do not move and the length of the muscle does not change but the sarcomere shortens. In this contract, no external work is done but internetwork is performed.

Thus, Option-A is the correct answer.