Relation between Ground Reaction Forces and Throwing Performance towards Known and Unknown Visual Target in Team Handball

Ioannis A. Bayios1 & Konstandinos D. Boudolos2

1Division of Games and Sports, 2Division of Sport Medicine and Biology of Exercise, Department of Physical Education & Sport Science, University of Athens, Hellas

Abstract

The aim of this study was to examine the relationship between Ground Reaction Forces (GRF) and performance of throwing above the shoulder towards known and unknown visual target. Fifteen elite handball athletes of the A1 League and 15 physical education students performed in total 10 throwing attempts each, with a cross-over step, under conditions of known and unknown visual target. The foot contact before the throwing attempt was made on an electronic force plate (Kistler, 9281, sampling rate 500 Hz ), whereas ball velocity as well as ball accuracy were measured by using separate specially designed electronic devices. There were no significant differences in the variables of throwing performance between the conditions of known and unknown target, except for the time of foot contact (p<.01). Significant relationships were observed be- tween GRF and throwing performance with regard to the lateral component mainly (ranging from 23.0 to 26.7 % and 27.5 to 33.5 % in the condition of known and unknown target, respectively) and not to the anterior- posterior (Y) and/or the vertical (Z) component, confirming the theory of energy transfer from the foot of contact to the opposite hand of throwing in order to achieve the highest velocity and the optimal accuracy.

Key words: GRF, throwing, accuracy, ball velocity, team handball