Movement Screening For Adolescent Runners: Relationship Between Single Limb Step Down Performance And Running Mechanics

Abstract

The single limb step down (SLSD) is a movement screen commonly used to assess neuromuscular control of the lower extremity. In adult runners, performance on the SLSD is predictive of running mechanics. However, it is unknown whether this is also the case for adolescent populations. If so, the SLSD could be a useful tool for injury risk screening in adolescent athletes. PURPOSE: Determine whether performance on the SLSD predicts running mechanics in adolescent runners. METHODS: 21 runners participated in this study (12 M/9 F; age: 12.38 ± 0.79 years; weekly mileage: 23.2 ± 6.4 miles; easy training run pace: 3.25 ± 0.17 m/s). Participants ran for five minutes on an instrumented treadmill after which 10 SLSD trials were performed bilaterally from a 15 cm box. Running and SLSD kinematics were recorded using motion capture. Peak frontal plane hip, knee, and ankle, and transverse plane hip and knee angles were calculated during both SLSD and running. The sum of the frontal plane angles was calculated to indicate total medial collapse (TMC). Five additional kinetic variables previous linked to running injuries were calculated for the running trials. Linear regressions were used to determine whether performance on the SLSD predicted kinematics or kinetics during running, with left and right limbs analyzed separately. RESULTS: Kinematics on the SLSD predicted kinematics during running (Figure 1). However, TMC during SLSD did not predict vertical loading rates (R2=.008, p=.568), peak hip adductor moments (R2=.021, p=.363) or impulses (R2=.007, p=.602), or peak knee abductor moments (R2=.014, p=.446) or impulses (R2=.039, p=.209) during running. CONCLUSIONS: The SLSD can predict kinematics during running in adolescent runners. However, performance on the SLSD does not provide information regarding kinetic factors associated with running injuries. Additional research is required to confirm the suitability of the SLSD for identifying adolescent runners at risk of injury.