Interlimb Asymmetry in Elite Soccer Players During Jumping and Change-of-Direction Tasks: Emphasizing Chronic Ankle Instability-Induced Contralateral Limb Deficit

Abstract

Background:

Chronic ankle instability (CAI) can induce contralateral limb deficits, influencing interlimb asymmetry during athletic tasks. Understanding the magnitude, direction, and individual thresholds of these asymmetries is critical for effective rehabilitation and performance monitoring.

Hypothesis:

CAI-induced contralateral limb deficits significantly influence the magnitude and direction of interlimb asymmetry in jumping and change-of-direction-speed (CODS) tasks.

Study Design:

Cross-sectional study.

Level of Evidence:

Level 3.

Methods:

Male elite soccer players with (n = 32) and without (n = 38) CAI performed single-leg hop (SLH), single-leg triple hop, modified-505 (Mod505), and 90°-changes-of-direction tests.

Results:

Paired-sample t tests revealed small-to-moderate differences between dominant and nondominant limbs in both groups (P < 0.05), moderate-to-large differences between injured and contralateral uninjured limbs (P < 0.05), large differences between injured and matched limbs of healthy players (P < 0.05), and small nonsignificant differences between contralateral uninjured and matched limbs of healthy players (P > 0.05). Independent-sample t test revealed asymmetries were significantly higher in all tests (P < 0.05) except for SLH (P > 0.05) in players with CAI. Kappa coefficient showed substantial-to-perfect agreements for players with CAI (κ = 0.71-1.00), and moderate-to-substantial agreements for healthy players (κ = 0.51-0.73), indicating asymmetries favored same limb. Agreement percentages for similar identifications of asymmetry patterns based on individual thresholds derived from intralimb variability revealed that injured players adopted similar patterns in CODS (81.25%), while healthy players adopted similar patterns between SLH and mod505 (76.32%).

Conclusion:

CAI-induced contralateral limb deficits influenced magnitude and direction of asymmetry, potentially underestimating asymmetry. Asymmetry consistently favors the same limb due to injury and functional similarities; thresholds derived from intralimb variability identify real asymmetry.

Clinical Relevance:

These findings highlight the importance of considering contralateral limb deficits when interpreting interlimb asymmetries in players with CAI. Rehabilitation programs should address these deficits to optimize performance and reduce injury risk.