The anterior single leg hop for distance (SLHOP) is a commonly utilized functional test for performance and return to play, but limited data exist regarding its prospective ability to detect injury risk. The Functional Pre-participation Physical Evaluation (FPPE) project is a nationwide preseason screening evaluation aimed at assessment of high school athletes’ lower extremity (LE) musculoskeletal injury risk.
PURPOSE: To determine if LE injury risk can be predicted by SLHOP side-to-side asymmetry in healthy high school athletes.
METHODS: Prior to the start of their respective sports seasons, 1,726 high school football, soccer, basketball and lacrosse athletes (15.7±1.3 y, 1.72±0.11 m, 68.9±15.3 kg) performed the SLHOP. The average distance of three SLHOP trials was calculated for each limb and then normalized to the respective limb length. Limb symmetry index (LSI) values were calculated as the ratio of the lower average distance to the higher average distance. Asymmetric athletes were defined as having an LSI value of 85% or less (n=94). Certified Athletic Trainers (ATs) using the national surveillance tool, High School RIO, collected LE injury data (n=218 injuries reported). An injury was defined as requiring medical care from a physician or AT and resulting in at least one day lost from athletic participation. An independent samples t-test (a-priori alpha=0.05) was conducted to examine the effects of SLHOP asymmetry on LE injury occurrence. A relative risk ratio (RR) was calculated to determine the risk of LE injury for asymmetric SLHOP athletes relative to symmetric athletes.
RESULTS: The LE injury rate was 2.35 times higher in asymmetric athletes compared to symmetric athletes [RR=2.35, 95% CI= 1.65,3.34] (p<0.0001). SLHOP LSI was significantly different between the injured and non-injured athletes (injured = 93.1%±7.4%, non-injured = 94.5%±5.1%), p<0.006).
CONCLUSIONS: SLHOP asymmetry assessed during pre-participation physical examinations may be an indicator of LE injury risk in high school populations. These preliminary results are aimed at identifying indicators of injury risk as an important step towards developing a functional component to current pre-participation physical evaluations.
Supported by NIH Grant 5R01-AR062578-02.