Phase Specific Comparisons of High and Low Vertical Jump Performance in Collegiate Female Athletes

Countermovement vertical jump testing has become a staple in athlete assessment protocols. As the popularity of jump testing has grown, a need and interest has also grown in identifying the factors that underpin high-level outputs. As jump height alone as a variable in evaluating vertical jump performance has been questioned in athletic populations, other variables such as the reactive strength index modified (RSIm) allow for not only evaluating the outcome, but the strategy used in obtaining that outcome.

Thus, the purpose of this investigation was to examine the differences in high and low vertical jump performances, as determined by the RSIm in female collegiate athletes.

Thirty NCAA Division Ⅰ female volleyball and basketball athletes performed countermovement vertical jump trials on a force platform. The sample was then broken into two groups as determined by median RSIm values. Independent sample t-test were then used to compare groups.

High RSIm group displayed greater jump heights (P < 0.05). Additionally, the high performing group displayed lower eccentric duration times (P < 0.05). No differences between groups were seen in kinetic variables.

The high performing group displayed faster eccentric times which translated to lower values in time to take-off though not statistical significant. The higher RSIm values appear to be a result of both greater jump heights and reduced time to take off. Thus, focus being placed on the speed of the movement during training would be of benefit in improving RSIm values.