Relationship Between Single Leg Reactive Strength Index and Overuse Injuries in Collegiate Middle-Distance and Distance Runners

Introduction: Single leg reactive strength index (RSI) is a measure of jump height over ground contact and is used to measure plyometric performance in athletes. The purpose of this study was to examine the relationship between RSI and injury rates in collegiate middle-distance and distance athletes. Methods: In a double blind, prospective correlation design that took place over an eight-week indoor track and field season, 42 middle-distance and distance athletes had their bilateral single leg RSI tested on a weekly basis. Injury questionnaires were handed out at the beginning of every week to collect location and severity of the athlete’s injuries over the previous 7 days. Results: Athletes were found to have significantly higher rates of right leg injuries (N=197) as opposed to left leg injuries (N=86) (p < .05) over the eight-week period. Difference in RSI between event groups and sexes were shown to be significantly different (p <.05). Injury rates were shown to have no significant difference (p >.05) between event groups when combined and measured with only male or female subjects. When mean RSI values over the eight-week period were broken down into quartiles, the left leg RSI was shown to be a clear indicator for right leg injury. Conclusion: These results suggest that RSI can be used as predictor of injury in middle-distance and distance track and field athletes.