A018: Impact of Unanticipated and Backhand Area Smash Landing on Female Badminton Players’ Lower Limb Biomechanics

Abstract

In badminton, lower limb injuries frequently occur during unanticipated smash landing movements. Additionally, the risk of lower limb injuries may vary depending on different landing strategies. This study aims to investigate the impact of unanticipated factors and two types of smash actions in the backhand area on lower limb biomechanics. Method: A motion capture system (Motion Analysis Raptor-4, USA) and Kistler force plates (model 9287B, 90 cm × 60 cm × 10 cm, Kistler Instruments AGCorp., Switzerland) were used to collect biomechanic data of 13 female athletes during backhand rear-court jump smash (BRJS) and backhand lateral jump smash (BLJS) in both anticipated and unanticipated conditions. Statistical analyses were performed using SPSS 17.0 (SPSS Inc., Chicago, IL, United States). A 2 × 2 repeated measures ANOVA (jump smash movement × expected condition) was used to analyze the effects of the jump smash movement and expected conditions on lower limb biomechanics. When the main effects were significant, post-hoc comparisons were conducted using paired t-tests with Bonferroni correction. Open-source software package spm1d (http://spm1d.org) in MATLAB R2019a (The MathWorks, Natick, MA, USA) was used for analysis. The results indicated that BRJS and BLJS resulted in higher vertical instantaneous load rates (p= 0.003, =0.314) and knee extension moments (p= 0.013, =0.231) at initial contact (IC) under unanticipated conditions. The main effect results indicated that BRJS had greater knee abduction angles (p= 0.03, = 0.182) and knee adduction moments (p= 0.01, =0.248) at IC than BLJS, while the interaction effects showed that BRJS had a greater frontal plane center of pressure displacement under unanticipated conditions (p= 0.041, = 0.186). BLJS showed greater knee extension moments (p= 0.013, =0.231) and smaller knee (p= 0.002, = 0.347) and hip (p \u3c 0.001, = 0.491) flexion angles at IC compared to BRJS. Additionally, BLJS demonstrated higher peak ankle internal rotation moments (p= 0.018, =0.212) than BRJS, with a greater peak ankle inversion moment under unanticipated conditions. Conclusions/Discussion: Unanticipated factors significantly impacted the biomechanics of both smash landing actions, potentially increasing the risk of ACL injuries. Moreover, nanticipated factors may increase the risk of ankle sprains during the BLJS movement