Bounce diagnostics

The analysis of jumping ability is carried out in the biomechanics laboratory of the Institute of Sport and Sports Science at the University of Kassel using a standard jumping force diagnosis. The ground reaction forces for three different types of jump (squat jump, counter movement jump, drop jump) are recorded using a three-dimensional measuring pressure plate (Kistler, Winterthur) and parameterized in a computer program using various characteristic values (including an estimation of the increase in the body's centre of gravity using a time-of-flight method and an impulse method).

The squat jump is a vertical jump performed from a squatted body position. The upper body is slightly bent forward before the jump so that the hip and knee angle is around 90 degrees. The hands are fixed on the hips during the entire jump in order to minimize the influence of the arms to increase momentum. The task of the test subjects is to jump as high as possible from rest and without an initial lunging movement.

The counter movement jump is a vertical jump with a lunge, which is initiated from an upright body position and is characterized by a stretch-shortening cycle (DVZ). The lunge movement should be performed quickly downwards to the starting position of the squat jump. The hands are fixed on the hips during the entire jump in order to minimize the influence of the arms to increase momentum. The task of the test subjects is to jump as high as possible from an upright standing position after an initial lunging movement. This type of jump is used to assess the reactive force capacity for self-initiated stretching of the leg extensor muscles.

The drop jump is characterized by a low-high jump that is executed from a predetermined low jump height and is characterized by a stretch-shortening cycle (DVZ). The low jump movement should be executed from the base in such a way that the body's center of gravity is lowered as little as possible before the free fall. The hands are fixed on the hips during the entire jump in order to minimize the influence of the arms to increase momentum. The task of the test subjects is to jump upwards after the lower jump, bouncing as much as possible and without striking the heel. This type of jump is used to assess the reactive force capacity for externally-initiated stretching of the leg extensor muscles.