Title: “Inter-limb asymmetries in functional performance and non-contact lower-limb injury in pediatric-age athletes”
Supervisory Committee: Dr. Darren Warburton (Research Supervisor), Jack Taunton, Shannon Bredin
University Examiners: Drs. Kishore Mulpuri, Alexander Scott
External Examiner: Dr. Anthony N Turner
Chair: Dr. Hendrik Michiel Van Der Loos
Abstract:
Background: Previous findings regarding the association between inter-limb asymmetries in functional performance and lower-limb injury in sports are highly inconsistent, and there is a lack of research focusing on pediatric-age athletes.
Purpose: To comprehensively examine inter-limb asymmetries in lower-limb functional performance and their association with non-contact lower-limb injury in pediatric-age athletes.
Methods: A narrative (Chapter 2) and systematic (Chapter 3) review were composed to provide background and identify gaps. A retrospective survey was conducted to compare injury risk in laterally vs. non-laterally dominant sport in 6-17 y athletes (Chapter 4). Inter-limb asymmetry in lower-limb functional performance was assessed for 9-11 y fencers and taekwondo athletes to examine the asymmetry profile in child athletes specialized in laterally vs. non-laterally dominant sport (Chapter 5). To explore whether inter-limb asymmetry can predict injury, 456 taekwondo athletes (6-17 y) were assessed for asymmetries in unilateral jumps and Star Excursion Balance Test (SEBT), and then prospectively traced for injury for 12 months (Chapter 6). Lastly, inter-limb asymmetry in lower-limb functional performance was assessed for 9-11 y taekwondo athletes at the rested and fatigued state to explore the effects of fatigue on asymmetry (Chapter 7).
Results: Greater risk of non-contact lower-limb injury was shown in athletes specialized in laterally vs. non-laterally dominant sports (Chapter 4). Inter-limb asymmetries were demonstrated in both laterally and non-laterally dominant sport, with a limb by sex interaction (Chapter 5). The increase in inter-limb asymmetry in single-leg countermovement jump height indicates greater risk of non-contact lower-limb injury in both sexes, while the increase of inter-limb asymmetry in hop and triple-hop distance indicates greater risk of non-contact lower-limb injury only in boys (Chapter 6). Inter-limb asymmetry in triple-hop distance increased with fatigue; inter-limb asymmetry in anterior reach distance in SEBT decreased with fatigue (Chapter 7).
Conclusions: The current findings have important implications for pediatric sport. Inter-limb asymmetries were shown in childhood-age athletes in both laterally and non-laterally dominant sports; the amount of asymmetry can be affected by fatigue. Inter-limb asymmetries in unilateral jumps can be used to evaluate risk of non-contact lower-limb injury in pediatric-age athletes, while there is a difference between sexes.