title: Relationship between reactive strength variables in horizontal and vertical drop jumps.
abstract: The aim of this study was to investigate the relationship between reactive strength in a vertical and a horizontal drop jump (DJ). Subjects (n = 28) with previous jump training experience, performed 6 vertical DJs and 6 horizontal DJs from a 0.4-m box. Contact time, height jumped, distance jumped, and reactive strength index (RSI) were calculated and analyzed. Typical error measurements (TEMCV%) and intraclass correlations (ICCs) were used to assess the intrasubject reliability. Relationships between jumps and within jumps of the aforementioned variables were assessed using ICCs. The ICC (r > 0.789) and the TEMCV% (<10%) indicated good reliability for both vertical and horizontal DJs across each variable. Contact time showed no relationship between jumps (r = 0.222) and had no effect on the vertical DJ height (r = 0.152) or horizontal DJ distance (r = 0.261). The RSI correlation (r = 0.533) indicated a large relationship between reactive ability in the horizontal DJ and the vertical DJ. Contact times were significantly lower in vertical DJs compared with horizontal DJs (p < 0.0001). This study indicated that horizontal DJs are reliable and may be better used to train reactive movements that do not require brief contact times.
authors.affiliation: Department of Sport Studies, Faculty of Health, University of Canberra, Bruce, Australian Capital Territory, Australia. nick.ball@canberra.edu.au
authors.forename: Nick B
authors.initials: NB
authors.lastname: Ball
authors.forename: Sara
authors.initials: S
authors.lastname: Zanetti
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology; D008297:Male; D009068:Movement; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D059385:Plyometric Exercise; D011897:Random Allocation; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult