Developing a numerical method to profile the force trace from a countermovement jump and how these properties correlate to locomotive tests

The primary purpose of this research was to develop a numerical method for analysing the structure of a ground reaction force (GRF) trace of a countermovement jump (CMJ). The secondary aim was to perform a cross-sectional comparison between these properties and locomotive tests. Twelve elite female netballers participated in the two testing sessions, which were one week apart. Session one involved countermovement jumps (CMJ), drop jumps (DJ), hops, and triple-hops. Session two involved 10-meter accelerations, and a change of direction (COD) test. Force trace properties were derived from each athlete’s CMJ which had the highest peak vertical displacement (PVD) of the centre of mass (COM). Pearson correlation was performed to determine the strength of relationship between these properties and each locomotive test, per athlete. Results showed several significantly strong correlations between these properties and a 10-meter acceleration; of these, stronger correlations were found between CMJ properties which started from end of free fall (EFF) than those which started from the decent. These included the total impulse from, decent to toe off and EFF to toe off, (r = 0.733, p = 0.007) (r = 0.835, p = 0.001) respectively; total time of the CMJ from, decent to toe off and EFF to toe off, (r = 0.791, p = 0.002) (r = 0.859, p < 0.005) respectively. Properties of a CMJ GRF can be used to provide a numerically based method which describes the curve’s structure. These properties show which aspects of the curve correlate to a 10-meter acceleration.