查看文章

Methods: Eight subjects sat on a purpose built experimental chair and were fixed in position with waist and shoulder straps. Subjects performed an instep kick at maximum effort. Knee range of motion was from about 90 deg to 0 deg. Electromyographic activity (EMG) was recorded from the Sol and TA with bipolar surface electrodes. The TA of the kicking leg was stimulated percutaneously with rectangular pluses of 1ms duration, delivered to the tibial nerve. The electrical stimulation was delivered randomly around the moment of ball impact. TA H-reflex was observed during the activation of agonistic and antagonistic ankle muscles.

Results and discussion: There were individual differences in TA-EMG activity at ball impact whereas Sol showed little change from-100ms to 100ms at ball impact (0ms) in most subjects. Furthermore, the ratio of TA and Sol activity (TA/Sol ratio) also changed with different timing of ball …