Bob tried to open a jar of pickles,but the lid did not budge.As he struggled against the unmoving lid,the muscles of his hands and arms were
A) in isometric contraction.
B) in dynamic contraction.
C) locked in a stretch reflex.
D) in motor pools.
E) in extension.

Question

Quizplus · Accepted Answer

Isometric contraction occurs when there is tension in the muscle, but no movement in the joint. In this case, Bob's muscles are contracting against a force (the lid of the jar) but there is no movement of the joint (in this case, his wrist). Therefore, the correct answer is A) in isometric contraction.

Bob Tried to Open a Jar of Pickles,but the Lid