Lower preseason reactive strength index scores are associated with injury in female collegiate volleyball players but not male collegiate basketball players

Abstract

Objectives: Functional tests are used by sports medicine professionals to discriminate injury risk in athletes. One test that has shown promise is the drop vertical jump (DVJ); however, it is primarily used to evaluate measures associated with anterior cruciate ligament injury. The DVJ test can also be used to calculate the reactive strength index (RSI); a measure used to assess an athlete's power. The ability of the RSI to discriminate injury risk is unknown. The purpose of this study was to prospectively evaluate the ability of preseason RSI scores to identify athletes at risk for a noncontact time-loss injury to the low back or lower extremities.

Design: Prospective cohort.

Methods: One hundred and fifty-five male collegiate basketball (BB) players and 117 female collegiate volleyball (VB) players were recruited for this study. DVJ tests were performed in a motion capture lab.

Results: Female VB players with a RSI 0.9125m/s or less (30.48cm box) were 4 times (relative risk=4.2 [95% CI: 1.0, 17.7]; p-value=0.024) more likely to be injured. There was no association between preseason scores and injury in the male BB athletes.

Conclusion: RSI scores should be collected for female collegiate VB players as part of a preseason screen.

Keywords: Drop vertical jump; Force plates; Injury; Jumping; Reactive strength index.