| Comparison of Soleus and Tibialis Anterior Muscle Forces During Gait Initiation Between Individuals With and Without Chronic Ankle Instability |
| Paper ID : 1795-SPORTCONGRESS |
| Authors |
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Khorshid bijari *1, حیدر صادقی2, محمد یوسفی2 1PhD students of biomechanics, Department of physical education and sports sciences, Kharazmi University, Tehran, Iran 2استاد |
| Abstract |
| Introduction: Muscle force generation is a fundamental component of neuromuscular function assessment during dynamic motor tasks. Investigating muscle force patterns and center of pressure (COP) displacement during the anticipatory postural adjustment (APA) phase of gait initiation offers crucial insight into the sensorimotor control mechanisms underlying balance regulation, particularly in individuals with chronic ankle instability (CAI). This study aimed to compare the estimated muscle forces of the soleus (SOL) and tibialis anterior (TA) during the APA phase of gait initiation between individuals with CAI and healthy controls. Methods: Thirty-two participants (16 with CAI and 16 healthy controls) voluntarily participated in this study. Participants initiated gait at a self-selected speed while standing on a forceplate. Ground reaction force data were used to determine APA duration and normalized peak anteroposterior COP displacement. Muscle forces of SOL and TA were estimated using a musculoskeletal modeling approach in OpenSim, based on inverse dynamics and static optimization analyses. Results: The CAI group demonstrated significantly lower SOL muscle force compared to healthy controls (p = 0.038), whereas no significant difference was found in TA muscle force between groups. Additionally, individuals with CAI exhibited significantly shorter APA duration (p = 0.002) and reduced peak anteroposterior COP displacement (p = 0.010). Conclusion: The reduced APA duration and diminished COP displacement in individuals with CAI indicate impaired feedforward postural control. These findings suggest that deficits in higher-level neural regulation may compromise anticipatory stabilization mechanisms. The observed reduction in SOL muscle force points to weakened plantarflexor contribution, limiting forward COP progression and effective balance control. In contrast, the relatively preserved TA activation alongside diminished SOL output may reflect altered intermuscular coordination. Collectively, these results highlight the crucial role of SOL activity and feedforward neuromuscular regulation in maintaining postural stability during gait initiation in individuals with CAI. |
| Keywords |
| Chronic ankle instability; Anticipatory postural adjustment; Gait initiation; Soleus muscle; Tibialis anterior; Muscle force |
| Status: Abstract Accepted (Oral Presentation) |
