Fig. 4.

Major patterns of responses of agonist and antagonist muscles to stretching of extensor muscles. A: the most frequent pattern—after SR responses of stretched muscles (elbow extensors in this example), a common inhibitory period (IP, rectangular box) with subsequent reactivation of all muscles occurred. B: as in A, common extensor IP was associated with a shorter-duration IP in the shortened flexor muscles. C: only stretched extensors had a common IP without detectable changes in the EMG activity of shortening flexors. Calibration bars for EMG signals: 200 μV for preloaded extensors and 25 μV for flexors (antagonists).