Which of the following events accompanies the rapid voluntary flexion of the arm?
An increase in the activity of the Ia afferent fibers from the biceps (the agonist) A decrease in the activity of the Ib afferent fibers from the biceps (the agonist) An increase in the activity of the Ia afferent fibers from the triceps (the antagonist) A decrease in the activity of the Ib afferent fibers from the triceps (the antagonist)