Author(s): WANG, Q., ZHOU, X., MA, Y., IMAI, K., CUI, M., MU, Z., YAN, H., Institution: HUAZHONG UNIVERSITY OF SCIENCE AND TECHNOLOGY, Country: CHINA, Abstract-ID: 1264

INTRODUCTION:
Football is a sport with a high risk of ankle sprains. More than 40% of players experience recurrent sprains or giving way, known as chronic ankle instability (CAI). Single-leg balance (SLB), bipedal landing (BL), and single-leg landing (SLL) tests are effective assessment methods for determining the presence of CAI. However, current SLB research mainly compares football athletes of different performance levels. Existing SLL and BL studies largely focus on landing time. Therefore, the purpose of this study was to compare biomechanical parameters between football players with and without CAI during SLB, BL, and SLL tests.
METHODS:
36 male soccer athletes were recruited and divided into CAI (n = 16) and non-CAI (n = 20) groups. Basic parameters were obtained through questionnaire. A Kinvent V3 force plate was used to collect data. The SLB test required participants to maintain a 10-second stance under both eyes-open (EO) and eyes-closed (EC) conditions. For the BL and SLL tests, participants were instructed to step off a 30 cm box and land on the force plate in accordance with the test protocol.
RESULTS:
Compared with the non-CAI group, athletes with CAI demonstrated significantly greater bilateral asymmetry and overall postural sway across single-leg tasks. Specifically, during both SLB-EO and SLB-EC tests, the CAI group exhibited significantly larger COP ellipse area. Under the SLB-EC condition, additional significant increases were observed in medial-lateral length, medial-lateral velocity. No significant between-group differences were identified during the BL test. However, during the more demanding SLL test, the CAI group demonstrated significantly bigger time to stabilisation and COP ellipse area.
CONCLUSION:
CAI is associated with impaired dynamic postural control and increased bilateral asymmetry, particularly during single-leg tasks. Athletes with CAI exhibited greater postural sway during SLB test, which was further exacerbated under EC conditions, particularly in the medial-lateral direction. This may be related to compromised subtalar joint function affecting inversion-eversion stability, consistent with previous single-leg balance findings [1]. No significant differences were observed in the BL test, possibly because greater energy absorption occurred at the hip (35.0%) and knee (35.3%) [2]. In contrast, deficits became evident during the single-leg landing task, where greater demands were placed on the ankle joint. These findings have practical implications for injury prevention and provide reference criteria for assessing functional recovery in athletes with CAI.
References
1. Liu N, Yang C, Song Q, et al. J Frontiers in Human Neuroscience, 2024.
2. Yeow CH, Lee PVS, Goh JCH. Hum Mov Sci 2011;30:624-635.