title: A comparison of two landing styles in a two-foot vertical jump.
abstract: In team sports, such as basketball and volleyball, the players use different takeoff styles to make the vertical jump. The two-foot vertical jump styles have been classified according to the landing style and identified as hop style, when both feet touch the ground at the same time, and step-close style, when there is a slight delay between the first and second foot making contact with the ground. The aim of this research is to identify the differences between the two styles. Twenty-three subjects participated in the study, of whom 14 were volleyball players and 9 were basketball players. The jumps were video recorded and synchronized with two force platforms at 250 Hz. Two temporal periods of the takeoff were defined according to the reduction or increase in the radial distance between the center of gravity (CG) and the foot support (T - RDCG and T + RDCG, respectively). The findings produced no specific advantages when both styles were compared with respect to takeoff velocity and, consequently, to jump height, but takeoff time was significantly shorter (p < 0.001) in the hop style takeoff. However, this reduction was compensated for by the greater time employed in the last step of the approach run (p < 0.001). When the step-close style was used, the vertical velocity of CG at the beginning of the takeoff is significantly lower. Moreover, the mean vertical force developed during T - RDCG was reduced by -627.7 +/- 251.1 N, thus lessening impact on landing. Horizontal velocity at the end of the takeoff is less when the step-close style is used (p < 0.005), suggesting that this style is better for jumps where it is necessary to move horizontally during the flight against an opponent.
authors.affiliation: Department of Physical Education and Sport, University of Granada, Granada, Spain. marcosgd@ugr.es
authors.forename: Marcos
authors.initials: M
authors.lastname: Gutiérrez-Davila
authors.forename: José
authors.initials: J
authors.lastname: Campos
authors.forename: Enrique
authors.initials: E
authors.lastname: Navarro
mesh_terms: D000704:Analysis of Variance; D054874:Athletic Performance; D001484:Baseball / Q000502:physiology*; D001490:Basketball / Q000502:physiology*; D001696:Biomechanical Phenomena; D005080:Exercise Test; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D010806:Physical Education and Training / Q000379:methods; D011336:Probability; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult