Postural control during complex tasks requires adequate sensory integration and somaesthetic reweighting: suboptimal postural strategies can lead to injury. We assessed the ability of healthy athletes to reweight somaesthetic signals during postural perturbations on different surfaces. Thirty-five young (16 ± 1 years), healthy, elite handball players participated in this cross-sectional study. Proprioceptive reweighting was evaluated via vibration of the triceps surae and lumbar muscles on firm and foam surfaces. Postural variables and the electromyographic activity of the gluteus medius (GM), semitendinosus (ST) and fibularis longus (FL) were recorded during the PRE (10 s), VIBRATION (20 s) and POST (20 s) periods. Ankle proprioception was predominantly used on the firm compared to foam support. However, two opposing behaviours were observed: a "rigid" strategy in which reliance on ankle proprioception increased on the foam, and a "plastic" strategy that involved a proximal shift of proprioceptive reliance (p < 0.001). The plastic strategy was associated with a more effective recovery of balance after vibration cessation (p < 0.05). ST activation was higher during POST in the rigid strategy and did not return to the PRE level (p < 0.05) whereas it did in the plastic strategy. Proprioceptive strategies for postural control are highly variable and future studies should evaluate their contribution to injury.
Keywords: ACL injuries; Plasticity; Proprioceptive reweighting; Sensory integration.
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