Question

Your school wins the homecoming football game against its biggest rival. You watch as the smallest cheerleader tries to lift up the heaviest linebacker in her excitement. As she strains against his 300 lb. load and does not move him, what type of muscle contraction are her muscles experiencing? Multiple Choice a) No contraction because she does not move him b) Isotonic c) Isometric

Answer 1

Answer:

c) Isometric

Explanation:

Isometric contraction is one where the muscle develops tension, but there is no change in its external length. In other words, isometric contraction is one in which the muscle contracts and produces force without any macroscopic changes in the joint angle. This is when we try to lift an object much heavier than we can handle, as the cheerleader shown in the question above tried to do. It seems that the mechanism of this contraction lies in the fact that the energy that would normally be exhibited as external mechanical work is used in the structural rearrangement of the fibers, ie the fibers shorten and the tendon lengthens, and some of the energy dissipates into heat. .