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Document Type

Abstract

Publication Date

12-1-2024

Abstract

PURPOSE: This study aimed to investigate whether reduced plantar cutaneous sensation could alter the movement strategies of the lower extremities in people with chronic ankle instability (CAI) during single leg drop landing.

METHODS: Fourteen adults with CAI were recruited (female: 6, age: 22.03±1.73 years, height: 1.72±0.11 m, body weight: 71.53±15.49 kg) in this study. Participants placed their bare foot on shaved ice for 10 minutes to reduce plantar cutaneous sensation sensitivity. The plantar skin sensation on the fifth metatarsal was measured with a set of Semmes-Weinstein monofilaments. The higher values indicated lower sensitivity and higher thresholds. The participants executed three single-leg drop landings from a 20-cm platform both before (pre-) and after (post-) ice immersion. The moment of landing was determined using a 20 N threshold in vertical ground reaction force. These indicators, including angle, angular velocity, range of motion (ROM) and net torque at the ankle, knee and hip, were measured using a motion capture system at 100Hz and a force plate at 1000Hz. Kinematic and kinetic indicators were filtered with low-pass filters at 10 and 50Hz, respectively. Joint torque was standardized using body weight. A paired-sample t-test was used to analyze data.

RESULTS: Plantar cutaneous sensation threshold (pre: 3.07±0.38 gauge, post: 4.12±0.28 gauge, p < 0.001) significantly increased after ice immersion. Peak internal rotation angle at the ankle (pre: 11.14±3.44, post: 10.16±3.67, p = 0.018), ankle ROM (pre: 16.63±3.90, post: 15.19±3.27, p = 0.011) and ankle angular velocity (pre: 353.50±110.94/s, post: 324.60±116.25/s, p = 0.033) were significantly decreased. Furthermore, peak adduction torques at the knee (pre: 0.13±0.27 Nm/kg, post: 0.34±0.33 Nm/kg, p = 0.02) and hip (pre: 0.06±0.05 Nm/kg, post: 0.30±0.25 Nm/kg, p < 0.001) were significantly increased, while hip internal rotation torque (pre: 0.72±0.20 Nm/kg, post: 0.55±0.17 Nm/kg, p < 0.001) significantly decreased after acute ice immersion.

CONCLUSION: Acute reduction in plantar cutaneous sensation induced by ice immersion primarily affected the internal rotation kinematics at the ankle and altered movement strategies of proximal segments at the knee and hip in the frontal plane. These adaptive changes highlighted the importance of sensory input in maintaining postural control during single leg drop landing in people with CAI.

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