Does proprioceptive reweighting contribute to reactive balance strategies during slip-like perturbations? a proof-of-concept in healthy adults

Falls commonly occur during walking, particularly when struggling to respond to unexpected perturbations. Proprioception plays a significant role in detecting body destabilization even before reactions to perturbations are required. This study investigates the contribution of proprioceptive reweighting strategies to reactive balance during walking. This cross-sectional, proof-of-concept study included fifteen healthy adults (18-40 years). Ankle and back muscle vibrators disrupted proprioceptive input in stance, allowing calculation of the proprioceptive reweighting index. Walk-slip perturbations were then administered on an ActiveStep treadmill. A linear regression model assessed the significance of proprioceptive reweighting in predicting post-slip stability (margin of stability). Participants shifted from an ankle-steered to a central-steered proprioceptive strategy on a foam surface with closed eyes (Difference = 15.70 % (SD=37.87), 95 %CI [0.41, 30.99], p = 0.045). The regression model explained 22.7 % of the variance in pre-touchdown margin of stability, with proprioceptive reweighting on foam significantly contributing to post-perturbation postural control (p < 0.001). Proprioceptive reweighting provides a moderate explanation for the mechanisms of reactive balance, highlighting that the key to effective balance recovery strategies may lie in the person's ability to both detect and respond to imbalances. Further research should explore if these proprioceptive strategies are a matter of directional control and if responses differ in older adults.