The main purpose of the master's thesis was to discover the influence of the maximal and explosive strength of the hip and trunk muscles on the length of the single-leg standing long jump, the single-leg standing triple hop for distance, the single-leg standing lateral jump and the height of the single-leg countermovement jump on a larger sample of top athletes. In addition, we wanted to check the influence of muscle strength asymmetries of the hip and trunk muscles and the functional ratios of the hip muscle strength on the results of single-leg jumps in different directions. 80 elite handball players (age 22 ± 4 years; body weight 90,8 kg ± 10 kg; body height 189,8 ± 5,6 cm) were included in the research. The measurement protocol consisted of three repetitions of a single jump with the dominant and non-dominant leg and three repetitions of a single unilateral isometric strength test of the hip (extensors, flexors, adductors, abductors) and trunk muscles (side flexors) with the dominant and non-dominant leg or side of the body. The strength of the hip and trunk muscles was evaluated with the maximum torque (Mmax) during the maximal isometric voluntary contraction and the rate of torque developement (RTD) during the explosive isometric contraction. With Pearson's correlation coefficient, we found a weak correlation between the strength of the hip muscles and the results of single-leg jumps (r = 0.23–0.29). On the basis of multiple regression analysis, we determined the influence of Mmax of hip adductors and the ratio between hip extensors and flexors RTD and hip abductors and adductors RTD on the length of the single-leg standing long jump (8.4–12.6% of the explained variance), the ratio between hip abductors and adductors RTD on the length of the single-leg standing lateral jump (6.1–7.6% of the explained variance), Mmax of the hip extensors on the height of the single-leg countermovement jump (5.8–8.5% of the explained variance) and Mmax of the hip adductors and abductors and functional ratios of hip extensors and hip flexors RTD on the length of the single-leg standing long jump (6–8% of explained variance). Trunk strength was unrelated to jump results. The main findings of our research are that athletes who are stronger and have smaller muscle strength asymmetries of the dominant and non-dominant leg achieve better single-leg jump results. In addition, the strength ratios between the antagonist muscles in the hip also have a significant influence on the results of jumps. Since the contribution of the strength of the hip muscles to the length or height of jumps varies depending on the direction of the jump, we recommend strength training of the hip muscle groups, which are related to the result of the jump in specific directions of movement for the sport in question.
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