Summary

The results of this research indicate that the SLSD test may be effective in identifying student athletes who are at an increased risk of lower extremity injuries.

Abstract

Objective

The primary research objective was to determine if performance on the Single Leg Step Down Test (SLSD) was associated with the occurrence of lower extremity (LE) injuries in high school athletes. We hypothesized that poorer performance on the SLSD test would correlate with higher LE injury rates among high school athletes.

The occurrence of LE injury among athletes of all ages is becoming more common, with over 3 million LE injuries seen in emergency rooms annually. Considering the cost and time out of sport following many LE injuries, interest in injury prevention mechanisms and more efficient injury screenings have increased. Numerous studies throughout the years have displayed a correlation between neuromuscular deficiencies in the trunk/hip muscle groups and lower extremity injury. Furthermore, core and hip strength has been linked with performance on the timed SLSD test. However, the relationship between performance on the SLSD test and LE injury risk has not been fully elucidated.

Methods

This prospective injury screening study included high school male and female student athletes ages 14-19 years old in school-sponsored sports. Exclusion criteria for this study included having sustained a LE injury within the past 6 months prior to testing, or any history of lower extremity surgery within the past year prior to testing. Each participant completed the 60-second timed SLSD Test on each leg during their school’s pre-participation physical exams prior to the start of their season. The students were followed prospectively, and lower extremity injuries sustained during the student athlete’s respective season(s) was reported via the school’s certified athletic trainer and a review of our institutions’ unified electronic medical record. Participants were followed for a period of 12 months after SLSD testing.

Results

A total of 336 high school athletes were included in this study. Fifty-five percent of the participants were male (n=182), with a mean age of 15.4 (±1.7) years. The average number of SLSD repetitions performed in 60 seconds was 18.9 (±8.65) for the left leg and 18.5 (±8.12) for the right leg. There were 21 injuries (6.25%). Participants performing in the top three quartiles for left leg SLSD repetitions had lower LE injury rates compared to those performing in the bottom quartile (HR=0.3, CI=(0.13,0.72), p=0.007). This relationship was not statistically significant for the right leg (HR=0.51, CI=(0.21,1.26), p=0.146). For every 10 additional SLSD repetitions performed within 60 seconds, the risk of injury decreased by 51% (right leg performance, HR 0.49, CI=(0.27,0.87), p=0.016) and 53% (left leg performance, HR 0.47, CI=(0.27,0.81), p=0.006).

Conclusion

The findings of this study suggest that the SLSD test could help identify student athletes at higher risk of lower extremity injury. Further research is needed to replicate these results and stratify injury risk by sex and sport, as well as to identify potential prevention strategies that could be informed by SLSD performance.