Yuri P. Ivanenko

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An electromyographic (EMG) activity pattern for individual muscles in the gait cycle exhibits a great deal of intersubject, intermuscle and context-dependent variability. Here we examined the issue of common underlying patterns by applying factor analysis to the set of EMG records obtained at different walking speeds and gravitational loads. To this end(More)
Despite distinct differences between walking and running, the two types of human locomotion are likely to be controlled by shared pattern-generating networks. However, the differences between their kinematics and kinetics imply that corresponding muscle activations may also be quite different. We examined the differences between walking and running by(More)
Muscle activity occurring during human locomotion can be accounted for by five basic temporal activation patterns in a variety of locomotion conditions. Here, we examined how these activation patterns interact with muscle activity required for a voluntary movement. Subjects produced a voluntary movement during locomotion, and we examined the resulting(More)
We studied the changes of vertical contact forces, lower limb kinematics, and electromyographic activity (EMG) at different speeds and gravitational loads. To this end healthy subjects were asked to walk on a motorized treadmill while the percentage of body weight unloaded (body weight support, BWS) was modified in steps by means of a well-characterized(More)
We investigated head and gaze orientation in six healthy volunteers walking along 90 degrees corner trajectories, both at light and with eyes closed. We found that head and eyes systematically deviated toward the future direction of the curved trajectory. Anticipation lead was about 1 s. Strikingly, the same behaviour was observed in darkness. In backward(More)
How rudimentary movements evolve into sophisticated ones during development remains unclear. It is often assumed that the primitive patterns of neural control are suppressed during development, replaced by entirely new patterns. Here we identified the basic patterns of lumbosacral motoneuron activity from multimuscle recordings in stepping neonates,(More)
The idea that the CNS may control complex interactions by modular decomposition has received considerable attention. We explored this idea for human locomotion by examining limb kinematics. The coordination of limb segments during human locomotion has been shown to follow a planar law for walking at different speeds, directions, and levels of body(More)
We studied the effect of support stability on postural responses to the vibration of Achilles tendons and of neck dorsal muscles in healthy humans. For this purpose we compared postural responses on a rigid floor and on 6 cm high rocking supports (see-saws) of different curvatures (different radii: 30, 60 and 120 cm). The subject stood with eyes closed, the(More)
Prevailing views on how we time the interception of a moving object assume that the visual inputs are informationally sufficient to estimate the time-to-contact from the object's kinematics. Here we present evidence in favor of a different view: the brain makes the best estimate about target motion based on measured kinematics and an a priori guess about(More)
We studied the effect of vibratory stimulation of different leg muscles [bilateral quadriceps (Q), hamstring (HS) muscles, triceps surae (TS), and tibialis anterior (TA)] in seven normal subjects during 1) quiet standing, 2) stepping in place movements, and 3) walking on the treadmill. The experiments were performed in a dimly illuminated room, and the(More)