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There is extensive experimental evidence linking instantaneous velocity to curvature in drawing and hand-writing movements. The empirical relationship between these characteristics of motion and path is well described by a power law in which the velocity varies in proportion to the one-third power of the radius of curvature. It was recently shown that a(More)
Human locomotion involves the coordination of the movements of the limbs to allow the subject to navigate in the environment. Here we study some curved locomotor paths with the hypothesis that, also during locomotion, movement obey the so-called 'two-thirds power law' stating that the angular velocity of the end effector (here the entire body) is(More)
This study investigated the patterns of rotational mobility (> or =20 degrees ) and stability (< or =20 degrees ) of the head and trunk in wild Indian monkeys during natural locomotion on the ground and on the flat-topped surfaces of walls. Adult hanuman langurs (Semnopithecus entellus) and bonnet macaques (Macaca radiata) of either gender were cine filmed(More)
Anticipatory head orientation relative to walking direction was investigated in humans. Subjects were asked to walk along a 20 m perimeter, figure of eight. The geometry of this path required subjects to steer their body according to both curvature variations (alternate straight with curved walking) and walking direction (clock wise and counter clock wise).(More)
We recorded the paths of subjects who walked along a memorized hexagonal route without vision, and studied the impact of previous mental simulation of this activity on how well the path could be reproduced from memory. We compared two kinds of mental simulation to actual physical practice, rest, or simple memorization of the path. The results indicated that(More)
Most studies about human locomotion only tend to consider single subjects walking alone in a stationary environment. Nevertheless, human subjects have often to plan and generate their locomotor trajectories according to one another's displacements. Therefore, in the present study we address the question of the interpersonal coordination when pairs of(More)
We herein studied whether arm-pointing movements from an upright posture (i.e. Belenkii's paradigm) toward various targets demanding a low degree of precision could influence associated anticipatory postural adjustments (APAs) and subsequent arm movements. Six subjects were asked to use their right arm to point (without finger touch) to targets of 2, 4 and(More)
Navigating consists of coordinating egocentric and allocen-tric spatial frames of reference. Virtual environments have afforded researchers in the spatial community with tools to investigate the learning of space. The issue of the transfer between virtual and real situations is not trivial. A central question is the role of frames of reference in mediating(More)
Trajectories of the hands and whole-body center of mass were studied during whole-body lifting tasks. The movements of different parts of the body were monitored with the ELITE system. Subjects were instructed to lift to shoulder height an object placed at one of two distances (5-45 cm) before them on the floor. The lifts were performed both with and(More)