The influence of center line width during the crossover hop test

Objectives: To assess the influence of center line width on crossover hop for distance test (XHOP) performance. Design: Repeated measures. Setting: University laboratory. Participants: 33 physically active females without history of a ligamentous knee injury (age: 22.5 +/- 2.3 years). Main outcome measures: Hop distance was measured during four XHOP conditions with variations in center line width: 2.54 cm (narrow), 15 cm (standard), 12.5% of the participants' height (HT1), and 25% of the participants' height (HT2). A repeated measures ANOVA was used to evaluate differences in hop distance for XHOP condition (narrow, standard, HT1, and HT2). Results: Differences in hop distance were shown on XHOP condition (p < 0.001). Post hoc tests identified differences in hop distance between narrow and HT2 (p < 0.001, Effect size (ES) = 0.78), standard and HT2 (p < 0.001, ES = 0.57), and HT1 and HT2 (p < 0.001, ES = 0.58) conditions, respectively. Conclusions: No differences in hop distance were identified between narrow and standard center line width XHOP conditions in healthy females. Decreased hop distance was shown when center line width was normalized to 25% of participant height in comparison to all other XHOP conditions, with medium effect sizes. This study highlights hop distance outcomes based on different XHOP center line widths, normalizing the XHOP according to height, and potential implications for frontal plane knee loading during the XHOP in healthy individuals. (c) 2020 Elsevier Ltd. All rights reserved.