Increased amplitude of cutaneous reflexes during human running as compared to standing.

摘要: Abstract The amplitude of H-reflexes is decreased during walking as compared to standing and a further reduction seen running walking. Does similar occur for reflexes elicited by cutaneous stimulation? To answer this question, the electromyographic (EMG) responses in biceps femoris (BF) tibialis anterior (TA) 20 ms train 5 electrical pulses, were recorded. This stimulus was applied sural nerve at ankle, either 16 different phases step cycle human volunteers on treadmill 8 km/h or isometric contraction levels TA BF same subjects standing, imitating postures cycle. mean latency main all 76 ms. Similar (P2), with 79 6 10 subjects. For constant strength stimulation (2 times perception threshold) contractions early stance imitation, reflex ratio's (reflex/background) 1.07 0.53, respectively, while these 2 muscles 1.78 1.1. higher primarily due large facilitatory responses, which present most but rarely voluntary standing. At end swing phase, however, predominantly suppressive, difference amplitudes between depended intensity. 1.5×T (where T = both run conditions they significantly pulses 2.5×T. latter an increment depth suppression high intensities It concluded that task there is, comparison exception brief period swing, general enhancement reflexes. suggested contribute normal activation such