Anthropometric and demographic factors affecting distance hopped and limb symmetry index for the crossover hop-for-distance test in high school athletes.

STUDY
DESIGN: Prospective cohort study using a random selection from an accessible population.
OBJECTIVES: We examined anthropometric and demographic characteristics affecting distance hopped (DH) and limb symmetry index (LSI) in the crossover hop-for-distance test in uninjured high school athletes.
BACKGROUND: Between-subject comparisons of hop test results described by DH and LSI are common in the literature and clinical practice. The effect that anthropometric traits and demographic characteristics have on these measures is uncertain but must be known to correctly interpret hop-for-distance test results in research or to determine suitability of return to sports. METHODS AND MEASURES: For 201 high school athletes (age = 15.15+/-1.45 years, mean weight = 63.67+/-14.02 kg, mean height = 167.92+/-9.58 cm) completing the crossover hop-for-distance test, we recorded maximum DH for each leg and calculated the LSI of each subject. We performed 2 separate step-wise regression analysis models to develop predictive equations for DH and LSI.
RESULTS: Age (r = 0.36), weight r = 0.41), and body fat percentage (r = 0.58) were significant predictors of DH, with the regression model explaining 59% of the variability. None of the measured variables were significant predictors of LSI (r = 0.03). The regression model explained only 3% of the variability of LSI.
CONCLUSIONS: The LSI for the crossover hop-for-distance test can be compared among all individuals without subdividing into groups. Subject characteristics should be as homogeneous as possible when comparing DH among subjects or groups.