For Antagonistic Muscle Groups to Move a Limb, Flexor Contraction

Question

For antagonistic muscle groups to move a limb, flexor contraction occurs coincident with
A) contraction of the extensor.
B) relaxation of the extensor.
C) no changes in the extensor.
D) contraction of the tendon.

Accepted Answer

To move a limb, the flexor and extensor muscles work in opposing pairs. When the flexor contracts, the extensor must relax to allow movement. Therefore, flexor contraction occurs coincident with relaxation of the extensor.