Abstract

The aim of this study is to analyse technique in weight-lifters at international level, following the curves of vertical forces. This work, with the help of a strength platform, and a system of analysis of two-dimensional video, tracks down the different critical points that contribute to these curves throughout the lift and jerk in weight-lifting. Six international weight-lifters have each taken three lift and jerk tests, using weights at 70%, 80% and 90% of their best lifts. In the course of the lift we noticed three critical points: two maximum (7-71, F71) and (T,3, F,3) separated by a minimum (T72, F72). These points express from a cinematic and dynamic plane, the transitions of the technical phases. In the calculated data, as a whole, two variables of the weight-lifting bar system (1-73-1-,1 and F71/F70) and four variables studied on the cinematic video of the bar (maximum height, maximum height/stature, maximum height/leg length and average speed) show significant differences in the tests throughout the Wicolson tests. The use of a matrix of correlations (Spearman test), together with a matrix of probabilities, shows a high correlation between the different points. It is necessary to underline the importance of the critical point ((-71, F71) with respect to the other points and their repercussions on the cinematic variables of the bar (r=0.83, P<0.01) for F71 and DV maximum at 90% of maximum weight. The first summit of F71 force is reached more quickly and the force relations lessen (to be exact F71/ F70) respectively the same, to 1.65±0.10, then I.54±0.08 at 70% and 80% of the maximum. The decrease in the force relation F71/ Fz2 and the increase of F73/ F71, with respect to the cinematic variables of the bar, are significative of weight-lifting possibilities.