Anthropometric and Demographic Factors Affecting Distance Hopped and Limb Symmetry Index for the Crossover Hop-for-Distance Test in High School Athletes

Abstract

Bryce W Gaunt, P7; SCS, CSCS1David 7: Curd, MS2Study 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 2 1.45 years, mean weight = 63.67 2 14.02 kg, mean height = 167.92 2 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 (+ = 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 unctional tests are common assessments used by sports medicine clinicians and physical therapists.' Bandf defined functional testing as "the performance of 1 maximal effort of a functional activity or series of activities, in an attempt to indirectly assess muscle strength and power, and attempt to quantify function." He further stated that purposes of functional testing include "screening to determine asymmetry in the extremities that may predispose someone to injury, objective assessment of progress in a rehabilitation program, and an assessment of the ability of the extremity to tolerate external force^."^ From this definition, we infer that the information clinicians intend to gather and use for clinical decision making is either 1) characteristics inherent in the performance of the functional test (ie, muscular strength, power, proprioception) or 2) information resulting from an injury (ie, pain, decreased confidence in limb). Often, the effect that anthropometric (ie, weight), demographic (ie, age), or methodological issues can have on the results of functional tests is not Unrestricted between-subjects comparisons of DH and LSI results are commonly found in the literatUre2.4.5.9.10.13.14.19.24.26~5454~7-40 and in clinical practice when a "passing criteria" is necessary before discharge or return to sport. If DH or LSI is affected by anthropometric, demographic, or methodologic variables, then the current unrestricted use of DH and LSI comparisons be...

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