In the human knee-jerk reflex of a seated individual, as the calf moves from a vertical towards a horizontal position, the muscles of the quadriceps (on the anterior of the thighs) and the muscles of the hamstring (on the posterior side of the thighs) are ________.

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In the knee-jerk reflex, when the calf moves from a vertical towards a horizontal position, the quadriceps muscles are excited and contract to extend the leg, while the hamstring muscles are inhibited and relaxed to allow this movement. This is an example of reciprocal innervation.

In the Human Knee-Jerk Reflex of a Seated Individual, as the Calf