Qualification differences in interrelationships of takeoff variables in male long jumpers

The objective of this study was to explore the interrelationships between key variables of takeoff technique among long jumpers of various performance levels. Attempts of thirty-seven male athletes were filmed with a video camera, operating at 240 Hz, during their competitive performances in long jumps and analysed using 2D video analysis (SkillSpector software was used). The characteristics of takeoff movements of athletes who had effective distance from the first (7.54 m) to eighteenth (6.76 m) and from the nineteenth (6.74 m) to thirty-seventh (4.93 m) were compared. Correlation and multiple regression analysis were used to evaluate the interdependence between the characteristics of takeoff technique in long jump. It was found that jumpers of higher performance level had significantly larger takeoff velocity of the center of gravity (8.73 ± 0.43 and 8.24 ± 0.47 m.s-1, respectively), its horizontal (8.00 ± 0.41 and 7.68 ± 0.45 m.s-1) and vertical (3.48 ± 0.38 and 2.95 ± 0.43 m.s-1) components, and takeoff angle (23.5 ± 2.3 and 20.6 ± 2.5°). Also, they performed takeoff significantly faster (ground contact time 0.129 ± 0.009 and 0.140 ± 0.014 s, respectively). Only one strong or medium correlation was exhibited between the effective distance and kinematic takeoff characteristics in both groups of athletes (r = 0.71 between effective distance and knee angle at touchdown in the less qualified group). Multiple regression analysis identified knee angle at touchdown and takeoff velocity as key variables of long jump for less qualified jumpers.