Background:
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The single-leg hop for distance (SLHOP) is a commonly used functional performance measure to determine return-to-play readiness. However, it is unknown if functional performance at return-to-play can predict future patient outcomes. Therefore, the purpose of this study was to determine if SLHOP performance and symmetry at return-to-play following a lower extremity injury would predict lower extremity patient-reported outcomes six months post-injury.

Methods:
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Two-hundred thirty-six adolescent athletes (15.7±1.4 years, 171.1±7.6 cm, 70.3±15.3 kg) were recruited for this study. If an individual sustained a non-surgical lower extremity injury during their sports season and missed three days of sports participation they were eligible for follow-up functional and patient outcome assessment Thirty-two adolescent athletes were eligible and completed the follow-up testing (15.0±1.1 years, 166.5±4.9 cm, 67.3±10.4 kg; 14 American football, 8 volleyball, 4 girls' basketball, 6 boys' basketball athletes). The SLHOP was completed by affixing a tape measure to the ground and instructing the participant to hop on one leg as far as possible. Each participant performed three trials per leg at return-to-play (alternating legs). To be counted as a successful trial the participant maintained postural stability for 2 seconds after the landing and the contralateral leg was not allowed to touch the ground. The Pediatric Patient-Reported Outcomes Measurement Information System (PROMIS) Lower Extremity scale was completed six months after return-to-play as the patient-reported outcome measure. A stepwise multiple linear regression was conducted to predict PROMIS Lower Extremity scale score from SLHOP distance on the injured and uninjured leg (cm), and limb symmetry (%).

Results:
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At step one of the analysis, injured limb SLHOP distance was entered into the regression equation and was significantly related to the PROMIS Lower Extremity scale F(1,31)=20.8, p\<.001. The multiple correlation coefficient was 0.79, indicating approximately 62% of the variance of the PROMIS Lower Extremity scale scores could be accounted for by the injured limb SLHOP distance. Specifically, for every increase in one cm of SLHOP performance there would be an increase of 0.6 points on the PROMIS Lower Extremity scale. Uninjured limb SLHOP distance and limb symmetry did not enter into the equation at step two of the analysis (p\>.05).

Conclusion:
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The SLHOP conducted at time of return-to-play following a lower extremity injury can predict lower extremity patient-reported outcomes six months later. This indicates that clinicians may be able to use the SLHOP following an injury to not only determine return-to-play readiness but a successful long-term outcome.
