LAUSR

The purpose of this study was to investigate the effect of age on peak torque (PT) relative strength measures of knee extensors (KE) and knee flexors (KF), bilateral strength ratio (Q:Q, H:H), and ipsilateral strength ratio (H:Q) in youth e lite male football players.Elite male players (n = 70) from four age categories (U16: n = 20, U17: n = 20, U19: n = 15, U21: n = 15) perf ormed isokinetic strength tests using a Cybex dynamometer. Results show a significant effect of age on PTKE (F3,142 = 4.54, p = 0.005 , = 0.09) and PTKF (age: F3,142 = 3.07, p = 0.030, = 0.06). No significant effect of age on unilateral (F3,142 = 1.05, p = 0.375, = 0.02) or ipsilateral strength ratio (F3,142 = 2.63, p = 0.053, = 0.06) was found. Results revealed significant differences in PTKE for n ondominant limbs between U16 and U21. Higher bilateral differences were detected for flexors (H:H = 7.94–11.47 %, Q:Q = 7.97–9.29 %) compa red to extensors. Our study showed that 17-year-old players have levels of strength similar to U19 players. A higher bilateral diff erence of knee flexors than extensors was found, suggesting that more attention should be paid to knee flexors. No effect of laterality w as found for strength and strength asymmetries. Future research should also focus on ipsilateral strength ratio in late stage of maturation.