Effects of Varying Acceleration of Platform Translation and Toes-Up Rotations on the Pattern and Magnitude of Balance Reactions in Humans

作者: Tony Szturm , Bjorg Fallang

DOI: 10.3233/VES-1998-8504

关键词: AccelerationMagnitude (mathematics)TrajectoryAnklePhysical medicine and rehabilitationPositive feedbackBalance (ability)Displacement (vector)Translation (geometry)SimulationPhysics

摘要: Different movement synergies used to restore balance in response sudden support surface displacements have been described, which include the ankle synergy and a number of multisegmental synergies. The purpose this study was extend analysis effects stimulus magnitude on pattern scaling reactions larger magnitudes disturbances, other types particular, forward translations (FT), backward (BT), toes-up rotations (RT). In addition, we examined whether timing center body mass (CM) displacement is an invariant feature corrective responses varying disturbances. Thirteen healthy adults were subjected FT, BT, RT acceleration/velocity. disturbance induced by FT BT fundamentally different from that RT. requirement during rapidly translate CM forward/backward new position within displaced base support. For RT, minimize CM. As evidenced initial phase ankle, knee, hip angular anterior-posterior (A-P) foot pressure displacement, increased with increasing platform present findings are consistent view trajectory control variable, as timing, peak magnitude, time did not vary function However, for increase results demonstrate stability restored distinct consisted early knee flexion then dorsiflexion extension. plantar flexion. observed. All muscles recorded (tibialis anterior, soleus, gastrocnemius, hamstrings, quadriceps) activated range 60 170 ms onset displacement. muscle acceleration/velocity, while there significant effect acceleration/velocity response, is, hip, responses. indicate multiple sources spatial information necessary selection initiation appropriate meet requirements tasks. strongly endorse concept postural network recovery standing balance, opposed positive feedback through local segmental or long loop reflex circuits.

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