This study assessed the ability of a common functional test, the Single Leg Step-Down Test (SLSD) to predict athletes who might be at greater risk for lower extremity injuries and ACL injuries during the football season.

1. Performance on the Single Leg Step Down Test is
Associated with Lower Extremity Injury Risk in
High School Football Athletes
Matthew Choice MS, Olivia Wishman MS, Luke Bunch, DPT, Patrick
Cook PT, Cale A. Jacobs PhD, Mary Lloyd Ireland MD, Julie
Neumann MD, Jeremy M. Burnham MD
Jeremy M. Burnham, MD
Medical Director of Sports Medicine
Ochsner Health – Baton Rouge

2. I have nothing to disclose.
Disclosures
2

3. • Lower extremity injuries in adolescent athletes are
increasing at a staggering rate
• Implications of sports injuries are significant
• 20% of children in the United States with sports related
injuries miss one or more days of school
• Pediatric patients undergoing knee ligament surgery are
at risk of decreased academic performance
Background & Epidemiology
3

4. • ACL Injuries numbered 95,000 in 1991
• Currently 200,000-250,000 in 2006 (Boden, Griffin et al. 2000,
Mohammadi, Salavati et al. 2013)
• ACL Reconstruction (ACL-R) performed 50,000 times in
1995, 100,000 in 2006, 170,000+ annually 2014
• Estimated annual cost for ACL-R is over $1.5 billion
(Boden, Griffin et al. 2000)
• Long term complications of OA 10-100x greater in ACL
injured patients (Hewett and Myer 2011)
Background & Epidemiology
4

5. Mechanism – How Does It Happen?
• 70% are Noncontact
• Athlete’s body position is a critical, and potentially
modifiable, risk factor… (Burnham et al. 2017)
• Ireland described the mechanism of non-contact ACL
injuries in 1999
• “Position of No Return”
• “Proximal Link to a Distal Problem” (Reiman et al. 2009)

6. Ireland, M. L. (1999). Anterior cruciate ligament injury in female
athletes: epidemiology. J Athl Train, 34(2).

7. Literature – Hip/Core Strength and Injuries
• Weak Abduction and ER strength, as well
as increased hip adduction during gait, are
associated with PFP (Ireland, Willson et al. 2003, and
Noehren, Hamill et al. 2013)
• Increased hip strength can decrease
dynamic valgus knee loads (Myer, Brent et al. 2008)
• Weak ER/Abd predictive of LE injury (Leetun,
Ireland et al. 2004; Khayambashi et al. 2016)

8. Hewett, T. E., Myer, G. D., Ford, K. R., Heidt, R. S., Jr., Colosimo, A. J., McLean, S. G., . . . Succop, P. (2005).
Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament
injury risk in female athletes: a prospective study. Am J Sports Med, 33(4), 492-501. doi: 10.1177/0363546504269591

9. Core Stability & Trunk Strength
• High risk knee loads are likely the result of poor
control of body posture and trunk accelerations (Hewett
and Myer 2011)
• In non-contact ACL injury, lateral trunk motion with
the body shifted over one leg, was associated with high
knee abduction or medial knee collapse (Hewett and
Myer 2011)
• Excessive lateral trunk sway is associated with
increased ACL injury risk (Zazulak, Hewett et al. 2007)

10. Hewett, T. E. and G. D. Myer (2011). "The mechanistic connection between the trunk, hip, knee,
and anterior cruciate ligament injury." Exerc Sport Sci Rev 39(4): 161-166.

11. Football Non-contact ACL Injury

12. How do we measure hip & core strength?

13. Functional Tests: Single Leg Step-Down

16. Hop Tests
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17. Return to Play

18. Hypothesis
• Lower performance on the Single Leg
Step Down Test and Hop Tests would
correlate with higher incidence of lower
extremity injuries in high school athletes
• Goal: Early detection of at-risk athletes

19. Methods
• SLSD and SLH tests were administered to 83 high
school male American football athletes
• age range 14-19, mean 16 +/- 1.24
• Participants were monitored throughout the subsequent
football season for lower extremity injury
• Spearman’s rank correlation was used to assess the
relationship between test performance and lower
extremity injury
• Participants were also stratified into quartiles for each of
the tests based on performance. The chi-square test was
used to examine the relationship between quartiles and
injury risk

20. Single Leg Step-Down Test20

21. Results
• For the left leg, Lower performance on the SLSD test for
the was correlated with increased LE injury risk (p=0.02)
• Scoring in the lowest quartile for SLSD on the left LE
was also significantly correlated with left LE injury
(p=0.04, OR=4.0)
• No significant relationship existed between SLH
performance and LE injury, or right LE SLSD
performance and right LE injury.

22. Results:

23. Results:

24. Discussion: Strengths
• Prospective
• Possible early
identification of at
risk athletes
• Low cost, minimal
time for a test

25. Discussion: Weaknesses
• Left leg results only
• Leg dominance?
• Low sample size
• How many of these
injuries were non–
contact
• Application to other
sports
• Interventions

26. Neuromuscular Training Program
• 12 week NMT program (Mandelbaum et al. 2005)
• 3000 female soccer players
• Education, strengthening, stretching,
plyometrics, sports specific agility drills
replaced traditional warm up
• 74-88% reduction in non-contact ACL tears

27. Conclusion
• Poor preseason performance on for the left leg on the
SLSD test was associated with increased lower
extremity injury risk for that leg in high school American
football athletes
• This test could be utilized in the future to help identify
athletes at risk of lower extremity injury

28. Thank You
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