Influence of base of support size on arm pointing performance and associated anticipatory postural adjustments

Yiou, Éric; Hamaoui, Alain; Bozec, Serge Le

doi:10.1016/j.neulet.2007.06.034

Cited by 31 publications

(39 citation statements)

References 19 publications

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“…These data contrast with other studies that show increased velocity of voluntary movement in upper limb pointing (Yiou et al 2007) and arm pull (Cordo and Nashner 1982) when support is increased. Greater leg lift acceleration in the current study when no additional support was available possibly reflects the need to re-establish a bipedal base of support as soon as possible; however, this is at the expense of a greater postural perturbation.…”

Section: Changes In Focal Limb Movement With Changes In Supportcontrasting

confidence: 99%

Adaptive Changes in Anticipatory Postural Adjustments With Novel and Familiar Postural Supports

Hall

Brauer

Horak

et al. 2010

Journal of Neurophysiology

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Hall LM, Brauer S, Horak F, Hodges PW. Adaptive changes in anticipatory postural adjustments with novel and familiar postural supports. J Neurophysiol 103: 968 -976, 2010. First published December 2, 2009 doi:10.1152/jn.00479.2009. Anticipatory postural adjustments (APAs) serve to stabilize posture prior to initiation of voluntary movement. This study examined the effects of changes in postural support on APAs using novel and familiar support paradigms. We also investigated whether postural strategies were refined with practice and how the CNS responded when multiple supports were available. Twelve healthy subjects stood on dual force platforms and performed 20 randomized left and right rapid leg-lift tasks in response to a visual cue under four conditions: unsupported, bilateral handgrip, bite plate, and a combined handgrip and bite plate condition. Vertical ground reaction forces, electromyography of limb, trunk and jaw muscles, and forces exerted on the support apparatus were recorded. Shift in center-of-pressure amplitude and duration were reduced with increased support. Muscles were recruited in advance of the focal movement when able to contribute to stability, and activity was modulated based on the amount of support available. The CNS adapted anticipatory postural strategies immediately with changes in condition regardless of familiarity with the support; however, adaptation was only complete at the first repetition in conditions that involved familiar support strategies. Tasks that involved a novel bite strategy continued to adapt with practice. In the multiple support condition, both hand and bite strategies were immediately incorporated; however, the contribution of each was not identical to conditions where supports were provided individually. This study emphasizes the flexibility of the CNS to organize postural strategies to meet the demands of postural stability in both familiar and novel situations.

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Section: Changes In Focal Limb Movement With Changes In Supportcontrasting

confidence: 99%

Adaptive Changes in Anticipatory Postural Adjustments With Novel and Familiar Postural Supports

Hall

Brauer

Horak

et al. 2010

Journal of Neurophysiology

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“…where yM HC and y′M HC are, respectively, the mediolateral centre-of-mass position and velocity at heel contact, and ω 0 is the eigenfrequency of the body modelled as an inverted pendulum calculated as follows: where g = 9.81 m/s 2 is gravitational acceleration and l is the length of the inverted pendulum, which in this study corresponded to 57.5 % of body height (Winter 1990).…”

Section: Dependant Variablesmentioning

confidence: 99%

Influence of temporal pressure constraint on the biomechanical organization of gait initiation made with or without an obstacle to clear

et al. 2015

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“…Since the pioneer work of Belenkii et al (1967), it is known that rapid voluntary arm movements are preceded by dynamical and electromyographical (EMG) phenomena in the body segments composing the ''postural chain'' (Bouisset and Zattara 1987;Cordo and Nashner 1982;Massion 1992;Yiou et al 2007). These phenomena are termed ''anticipatory postural adjustments'' (APA).…”

Section: Introductionmentioning

confidence: 99%

Effect of lower limb muscle fatigue on anticipatory postural adjustments associated with bilateral-forward reach in the unipedal dominant and non-dominant stance

2010

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Voluntary arm movements are preceded by dynamical and electromyographical (EMG) phenomena in "postural segments" (i.e. body segments not directly involved in the voluntary movement) called "anticipatory postural adjustments" (APA). The present study examined how the central nervous system organizes APA under fatigued state of postural musculature elicited by series of high-level isometric contractions (HIC), i.e. corresponding to 60% of maximal voluntary contraction. Subjects (N = 14) purposely performed series of bilateral-forward reach task (BFR) under unipodal stance (dominant and non-dominant) before ("no fatigue" condition, NF) and after ("fatigue" condition, F) a procedure designed to obtain major fatigue in hamstrings. Centre-of-gravity acceleration, centre-of-pressure displacement, and electrical activity of trunk and leg muscles were recorded and quantified within a time-window typical of APA. Results showed that there was no significant effect of fatigue on the level of muscle excitation and APA onset in any of the postural muscles recorded. Similarly, no change in APA onset could be detected from the biomechanical traces. In contrast, results showed that the amplitude of anticipatory centre-of-pressure displacement and centre-of-gravity acceleration reached lower value in F than in NF. Similar results were obtained whether dominant or non-dominant leg was considered. The changes in biomechanical APA features could not be ascribed to a different focal movement performance (maximal BFR velocity and acceleration) between F and NF. These results suggest that, when fatigue is induced by HIC, the capacity of the central nervous system to adapt APA programming to the fatigued state of the postural muscle system might be altered.

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Influence of base of support size on arm pointing performance and associated anticipatory postural adjustments

Cited by 31 publications

References 19 publications

Adaptive Changes in Anticipatory Postural Adjustments With Novel and Familiar Postural Supports

Adaptive Changes in Anticipatory Postural Adjustments With Novel and Familiar Postural Supports

Influence of temporal pressure constraint on the biomechanical organization of gait initiation made with or without an obstacle to clear

Effect of lower limb muscle fatigue on anticipatory postural adjustments associated with bilateral-forward reach in the unipedal dominant and non-dominant stance

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