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The generation and execution of anticipatory postural adjustments (APAs) depend on the complex distributed neural networks, involving cerebral cortex (including premotor cortex and primary motor area), thalamus, basal ganglia, cerebellum, and divided into stratified mode and parallel mode. The basal ganglia and premotor cortex contribute to code the motor planning of APAs. Supplementary motor area and pedunculopontine nucleus in the brainstem co-regulate the timing of APAs. Primary motor area projects cortical motor fibers to target area during the initiation of APAs. The pontomedullary reticular formation integrates and projects fibers to the spinal cord. The cerebellum is mainly related to the coordinated coupling of muscles during APAs.
RESUMO
Objective To explore the effect of acute endurance exercise on the balance control,maximum contraction of the back extensor and the anticipatory postural adjustments(APAs) and compensatory postural adjustments (CPAs) of the lumbar vertebra.Methods Seventeen male students from a police college participated in this study voluntarily.Three tests were performed right before and after the 10000 meters run:the single foot standing test with eyes closed,maximum contraction test of the back extensor and arm-rising test.The maximum voluntary contraction (MVC) of the back extensor and the time of standing with eyes closed were collected.The sEMG activities of lumbar erector spinae(LES) and Lumbar multifidus(LMF) as lumbar stable muscles were recorded.The pre-activation time and integrated EMG of APAs and CPAs were calculated.Results Before and after the 10000 meters run,no significant difference was observed in MVC,but the time of single foot standing decreased significantly.On the condition of the internal postural perturbation,the LES was activated significantly earlier and the APAs IEMG of LMF decreased significantly after the run,but no significant difference was observed in the pre-activation time of LMF and APAs IEMG of LES.The CPAs IEMG of LES and LMF both decreased significantly after the run.Conclusions The acute endurance exercise of 10000 meters run does not cause fatigue of lumbar stable muscles,but it has an effect on the performance of body balance control.It has effects on the postural control strategies of the central nerve system in response to the internal sudden postural perturbation,resulting in the earlier pre-activation of LES to compensate the decreased activation magnitude of LMF.
RESUMO
The anticipatory postural adjustments can be more precise in reflecting the ability of posture control,which associate with two kinds of neuromuscular model.Anticipatory postural adjustments disorders are found in stroke patients with hemiplegia,such as delay of muscle activation time,decrease of muscle activation,degradation of muscle recruitment order and reduction of adaptability.