Related Experiment Video
Updated: May 16, 2026
Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
Interactive effects of drop height and visual deprivation on kinematic and electromyographic characteristics during
Lingyue Meng1, Lintao Kong2, Yubo Wang3
1Physical Education and Sports School, Soochow University, Suzhou, Jiangsu 215021, PR China; Rehabilitation Engineering Lab, Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA.
Abstract:
To investigate the interactive effects of landing height and visual feedback on the kinematic and electromyographic (EMG) strategies of functional ankle instability (FAI) individuals during single-leg drop landings.
Methods:
Twelve male participants with unilateral FAI performed single-leg drop landings from three heights (15, 30, and 45 cm) under visual presence (VP) and visual deprivation (VD). Kinematics and EMG activity of the vastus lateralis (VL), semitendinosus (ST), tibialis anterior (TA), and lateral gastrocnemius (LHG) were analyzed using a 2 × 2 × 3 (Limb × Vision × Height) repeated-measures ANOVA.
Results:
Three-way interactions were identified in knee flexion at initial contact, pre-landing hip angular velocity, and pre-activation of the VL and TA (p < 0.05). Under VD, the unstable side failed to modulate knee flexion and TA pre-activation between 15 cm and 30 cm, whereas the stable side maintained distinct height-dependent gradients. ST and LHG activation primarily exhibited height main effects (p < 0.05), although a Vision × Height interaction was found for LHG (p = 0.013), with higher activation under VD at 30 cm. Post-landing, TA exhibited a "phase-reversal," with significantly higher activation under VD than VP (p < 0.001). Furthermore, the stable side demonstrated significantly higher post-landing TA activation and ankle co-contraction than the unstable side under VD conditions (p < 0.05).
Conclusion:
Visual deprivation disrupts feedforward preparation and height-modulation strategies in FAI individuals, particularly at moderate mechanical loads (30 cm). The observed temporal shift from proactive pre-activation to reactive feedback-driven compensation, coupled with bilateral asymmetries, highlights a maladaptive sensorimotor reorganization that may increase the risk of recurrent injury.
