RELATIONSHIP BETWEEN SPRINT RUNNING PERFORMANCE AND GROUND CONTACT TIME IN JUMPING TEST IN YOUTH SOCCER PLAYERS

The aim of this study was to compare is there any relationship between sprint running performance and ground contact time in jumping test in youth soccer players. The sample included 39 youth soccer players (n=39) of different ages, (U 13=15, 57,09 +/- 8,03 kg, 169,04 +/- 8,34 cm, U 15=8, U 17=16, 66,91 +/- 8,47 kg, 176,6 +/- 4,37 cm, 69,85 +/- 5,42 kg, 177,61 +/- 7,46 cm) middle league. For each participant, the body height (cm), body weight (kg), maximal sprinting speed so as ground contact time in jumping test were measured. Conventional statistical methods were used. Pearson correlation coefficient P < 0.05 was taken as the limit of the significance in all statistical tests. Jumping test: Optimal vertical rebounds (maximal elevation at each jump) were executed from a standing position for 7 jumps. Another measured variable is maximal sprinting speed in 40 m. Passages were recorded with Witty Manager Software, photocells at 10 m, 30 m and 40 m. The time from 30 to 40 meter was used to calculate maximal sprinting speed in 40 meters. The results of the statistical analysis are shown in Table 1. The findings are that there is no significant correlation between these two variables (r = - 0,128, P = NS). Most studies have shown that shorter ground contact times are seen in faster subjects compared to slower subjects (Mann, 1986; Weyand et al., 2000; Morin et al., 2012; Lockie et al., 2013) but this is not always the case (Brughelli et al., 2011). Kugler and Janshen (2010) found that prolonging ground contact time led to greater propulsive forces during accelerated sprint running. The sprint component is determined by a number of factors and not just muscle stiffness and ground contact time, so we can assume that this variable is maybe not the main parameter in determining which athlete will be faster in 40 m sprint. Sprinting requires coordination, stability, and muscular power to successfully accomplish the cycle motion of the legs to achieve maximum horizontal speed.