Relationships between isokinetic knee strength, sprint and jump performance in young elite soccer players
Abstrakt
The aim of the study was to examine relationships between knee extensors and flexors strength, linear sprint performance and jump performance in elite youth soccer players. The monitoring was carried out with twenty-three Czech youth male soccer players, category U16 (age = 15.6+-0.4 years, height = 177.7+-6.9 cm, weight = 67.9+-8.7 kg) on the national team training camp.
Maximum peak muscle torque of knee extensors (PTE) and flexors (PTF) on both legs (PL - preferred leg, NL - non-preferred leg) during concentric contraction in angular velocities (60, 120, 180, 240 and 300o.s-1) were assessed by Cybex dynamometer (Cybex NORM (R), Humac, CA, USA). Results of PTE and PTE are listed in Table 1.1 PTE and PTE were higher at each of the tested velocities.
However, we have not found significant differences between the PL and NL at any of the monitored velocities (60o.s-1: F1,92 = 0.48; 120o.s-1: F1,92 = 0.09; 180o.s-1: F1,92 = 0.17; 240o.s-1: F1,92 = 0.19 and 300o.s-1: F1,92 = 0.19; p}0.05). Acceleration speed in sprint at 5m was 1.11+-0.07s and in sprint at 10m it was 1.87+-0.10s.
In the test of the maximum running speed (flying 20m), the players achieved time of 2.45+-0.12s. The assessment of power strength by means of jumps showed the following results: CMJFA = 40.19+-2.48cm; CMJ = 35.33+-2.74cm and SJ = 33.22+-3.30cm.
PT at the lowest velocity has not correlated in any of the tests neither for the PL (Table 1.2) nor for the NL (Table 1.3). CMJ significantly correlated only with PL's flexors strength at the highest velocity (p{0.01).
Any of the examined isokinetic strength parameters has not proved significant correlation with SJ test.