Does Early Specialisation Improve Drop Jump and Y-balance Performance in Junior Football Players?

Abstract

Sport specialisation has been defined as the intense involvement in a single sport to the exclusion of all other sports. Previous research has raised questions about potential negative consequences of specialising at a young age. The purpose of this study was to examine differences in drop jump and y-balance performance in junior football players based on level of specialisation. This was a cross-sectional observational study involving 35 male footballers aged 10.2 ± 1.1 years. Participants were grouped as high, moderate, and low specialised. Level of specialisation was determined using a survey on their sports participation history. Tests included anterior Y-balance test and drop jumps assessed using the Landing Error Scoring System (LESS). Between-group differences were analysed using one-way analysis of variance and chi-squared analysis with an a priori statistical significance level of p ≤ 0.05. Hedge’s g effect sizes were reported for all results. High specialised players displayed greater left leg relative reach than moderate (mean diff = 10.9% LL; 95% CI [2.2, 19.6]; p = 0.013; Hedge’s g = 0.78) but not low (mean diff = 5.0% LL; 95% CI[-4.0, 14.1]; p = 0.218; Hedge’s g = 0.39) specialised players. No other significant differences were observed in Y-balance performance. High specialised players displayed fewer LESS errors than moderate (mean diff = 2.75 errors; 95% CI [0.05, 5.48]; p = 0.009; Hedge’s g = -0.90), but not low (mean diff = 2.20 errors; 95% CI [-5.05, 0.65]; p = 0.101; Hedge’s g = -0.57) specialised players. ‘Knee flexion displacement’ was the only LESS criterion that differed significantly between groups, with errors more common in moderately specialised players (n = 9) than both high (n = 0) and low (n = 5) specialised players (p = 0.003). These results suggest early specialised junior football players may perform better in the drop jump and y-balance tests than their less specialised counterparts. Results suggest all players may benefit from participation in injury prevention programmes such as the FIFA 11+, in particular moderately specialised players.