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Records were made of electromyographic (EMG) responses of both upper limb muscles and the corresponding elbow joint movements following sinusoidal (0.3 Hz) isometric displacement of the elbow joint itself. Two motor conditions were tested. Firstly, the subjects had to control elbow position and secondly control joint torque. Randomly timed, flexing or(More)
Recordings of electromyographic (EMG) leg muscle activity, head and joint movements and platform torque were taken in healthy subjects within three age groups (approximately 6, 10 and greater than 22 years) standing upright upon a sinusoidally moving treadmill. The sinusoidal frequency was randomly changed between 0.5, 0.33 and 0.25 Hz, while the amplitude(More)
Amplitude modulation of the quadriceps tendon jerk reflex was investigated during the step cycle in normal human subjects. Reflex amplitude was compared with that obtained during a control stance condition, with "equivalent" levels of EMG activity and limb position. During gait there was a progressive decrease in the reflex amplitude early in the stance(More)
In order to investigate the influence of subjects' height in stabilization of body sway, postural EMG reactions were analysed following perturbation of posture during stance on a force measuring platform. Perturbing momenta of different strengths were unexpectedly applied at the back (level of the center of gravity) after being matched to the body weight of(More)
Perturbations of stance evoke purposive EMG patterns which are directed to hold the body's centre of gravity over the feet. Dorsiflexing rotation of the feet is followed by a monosynaptic stretch reflex response in the gastrocnemius muscle, succeeded by a late compensatory tibialis anterior activation. Backward translation of the feet elicits only a(More)
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