Bilateral symmetry of vertical time to stabilization in postural sway after double-leg landing in elite athletes with unilateral chronic ankle sprain

Abstract

Background: Lower limb asymmetry among athlete with unilateral chronic ankle instability (CAI) during bilateral landing can be a potential source of ankle sprain reinjury. The aim of study was to investigate the effect of bilateral symmetry of vertical time to stabilization (vTTS) in postural sway after double-leg landing (DLL) in elite athletes with unilateral CAI.

Methods: Twenty professional players with unilateral CAI and ten healthy controls were assigned to three groups (soccer, basketball, and control groups, n = 10 each). The postural balance during DLL tasks was assessed based on center of pressure (CoP) and vTTS. Multiple analysis of variance was conducted to statistically analyse the CoP and vTTS which followed by Bonferroni's post hoc test (P < 0.05).

Results: The vTTS of the injured foot was significantly longer in the soccer and basketball players than in the control players (P = 0.006, p < 0.001 respectively). The intragroup comparison showed a significant difference in the vTTS of CAI and uninjured feet among the basketball players (mean difference = 1.3 s). The basketball group exhibited a worse balance in CoP oscillations results between groups.

Conclusions: The findings suggested that symmetry between double-leg vTTS values, may be important as much as the sooner vTTS in reduced CoP oscillations and enhanced balance after DLL. Balancing exercises should achieve sooner vTTS in soccer players and symmetry in the double-leg vTTS of basketball players with unilateral CAI while maintaining static balance during dynamic-to-static postural changes to reduce recurrent ankle sprain.

Keywords: Basketball; Injury prevention; Postural control; Soccer; Stability.

Fig. 1

Flowchart of the study design

Fig. 2

Phases of double-leg landing task from the step. a Standing on the step, b Preparing for landing, c Landing begins, d Flying in the air, e Landing

Fig. 3

Win FDM-S software, the image shows the average load distribution under the feet. The color scale on the left quantifies the load distribution. a The horizontal pink line is the connecting line of the three CoPs (Center of pressure). The middle cross is the center of pressure of the whole body. The ellipse around includes 95% of the CoPs. Minor axis (CoP displacement in mediolateral direction), Major axis (CoP displacement in anteroposterior direction)