Journal ArticleDOI
Forward and backward axial synergies in man
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TLDR
It was found that upper trunk movements are accompanied by movements of hip and knees in the opposite direction, resulting in a slight displacement of the center of gravity projection on the ground.Abstract:
1. Upper trunk and head forward and backward movements were analyzed in human subjects standing on a force platform. EMG of several flexor and extensor muscles was recorded together with the kinematics of the movement (EL.I.TE. system). 2. It was found that upper trunk movements are accompanied by movements of hip and knees in the opposite direction, resulting in a slight displacement of the center of gravity projection on the ground. 3. In fast movements, all the body segments were displaced at the same time, which suggests a feedforward control, whereas in slow movements, onset of displacement of the body segments was found to take place sequentially in a cranio-caudal direction. 4. EMG analysis during fast movements revealed two different types of control, utilized in forward and backward movements. With forward bending movements the action of two sets of muscles could be recognized: the prime mover (R. Abd.), the activation of which was not correlated with that of the other muscles and preceded the onset of movement with a fairly constant lead, and a group of postural muscles, the activation (VM, TA) and inhibition (Sol) of which were closely correlated. By contrast, with backward movements, the prime mover (Er.S.) and the postural leg muscles (Hamstrings, Sol) were activated simultaneously. In both cases, a feedforward type of control is evident. 5. Performance of the fast forward movements was accompanied by an initial forward displacement of the knee. The function of this phenomenon is discussed in term of a destabilizing action favouring the forward bending of the body or a prestretching of the knee extensor muscles increasing the strength of their subsequent contraction.read more
Citations
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Movement, posture and equilibrium: interaction and coordination
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Postural Orientation and Equilibrium
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The origin and use of positional frames of reference in motor control
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References
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Alan Stuart,S. Siegel +1 more
Journal ArticleDOI
Properties of postural adjustments associated with rapid arm movements
P. J. Cordo,L. M. Nashner +1 more
TL;DR: Postural muscle synergies were equivalent in muscle composition, relative activation magnitudes, and relative temporal sequencing and a conceptual model is proposed that suggests one simple way in which the reciprocal influence of postural set on postural and focal movement components and their temporal sequencing might be accomplished.
Journal ArticleDOI
Fixed patterns of rapid postural responses among leg muscles during stance
TL;DR: It is shown that in subjects employing FSR adjustments during stance activation patterns among leg muscles at FSR latency (functional stretch response, 100–120 msec) are preprogrammed prior to a response and are, on the average, fixed, independent of the associated motions among the ankle, knee, and hip joints.
Journal ArticleDOI
A sequence of postural movements precedes voluntary movement
Simon Bouisset,M. Zattara +1 more
TL;DR: Voluntary movement of the upper limb is preceded by postural movements occurring in the lower limbs and the pelvis that represent part of a central motor program and tends to reduce the early perturbations of the body's center of gravity.
Journal ArticleDOI
Elite: A Digital Dedicated Hardware System for Movement Analysis Via Real-Time TV Signal Processing
TL;DR: The system illustrated in this paper has been designed and developed particularly for automatic and reliable analysis of body movement in various conditions and environments and is based on real-time processing of the TV images to recognize multiple passive markers and compute their coordinates.