The Presence of Bilateral Imbalance of the Lower Limbs in Elite Youth Soccer Players of Different Ages

Abstract

The aim of this study was to examine bilateral differences in ground reaction forces (GRF), measured during a deep squat (DS) exercise, in a population of elite youth soccer players. Bilateral muscle balance is a key component in promoting musculoskeletal health of performers, yet there is a limited evidence base investigating such imbalances in youth. Seventy-four subjects were assigned to performance groups according to chronological age (younger than 13, 14, 15, 16, 17 years). Analysis of physical maturity status revealed that very few players were classified as "early" or "late" maturers. Players completed an overhead DS exercise, as part of preseason functional movement screening. Peak GRF were assessed using a twin force plate system. Significant differences (p ≤ 0.05) were identified between right and left side peak GRF for all groups except the youngest (U13) and oldest (U17). Nondominant "sides" showed the highest levels of PGRF across all groups. The magnitude of PGRF was not significantly different both within and between groups, except for the left side in the U13 to U15 groups (p = 0.04). Results from this study show that performance asymmetry is marked in adolescence. There seems a "trigger point" during the early stage of adolescence, when bilateral imbalances become marked. These differences do seem to reduce during the later stages of adolescence. Correct attention to focussed training, designed to remediate any imbalance, is warranted in adolescent groups. This is important with respect of the key associations between bilateral asymmetry and risk of injury.

Differences in plantarflexor function during a stretch-shortening cycle task due to limb preference

“…Asymmetry in lower limb function may be due to a variety of factors including lateralisation (Gabbard & Hart, 1996), sport and training background (Cavanagh, Pollock, & Landa, 1977;Cromie, Greenwood, & McCullagh, 2007), injury (Schiltz et al, 2009;Zifchock, Davis, & Hamill, 2006), speed of movement (Cavagna, 2006;Schiltz et al, 2009), age (Atkins, Hesketh, & Sinclair, 2013), muscle activation (Valderrano et al, 2007) or contextual interference (Vagenas & Hoshizaki, 1992).…”

Diagnóstico de assimetrias laterais em jogadores de futebol das categorias de base por meio do salto horizontal monopodal

“…Os resultados do presente estudo, bem como de outros estudos (2,16) fortalecem a ideia que a prática de futebol pode não levar a uma assimetria de força progressiva ao longo das categorias de base, contrariando o modelo teórico existente (12) . Nesse caso, os próprios jogadores de futebol utilizariam estratégias para que a força muscular de membros inferiores fosse desenvolvida simetricamente, apesar da demanda motora entre eles ser diferenciada.…”

“…Ao avaliar crianças no equipamento isocinético, não encontraram interação da assimetria medida em testes de flexão e extensão de joelho isocinéticos com a idade (16) . Para agachamento em plataforma com coleta simultânea de força, todos os grupos de idade apresentaram diferenças na força de reação de solo entre os membros inferiores direito e esquerdo força variando de 4 a 13%, mas não houve diferença entre as categorias (2) .…”

Lower extremity overuse injuries in the skeletally immature athlete

“…Functional movement screening and dynamic movement assessment also may be useful in identifying muscle imbalances that may put athletes at risk for both acute and overuse injuries. 79,80 The American Academy of Pediatrics has recommended that athletes take at least 1 day off per week. 81 Weekly training time, the number of repetitions, and the total distance should not be increased by more than 10% each week.…”