Kinematic Differences between Grab and Track Swimming Starts.

Abstract

The purpose of the present study was to investigate the differences in starting position between grab start, (grab) and track start, (track), in swimming and their influence in the rest kinematic characteristics of the two techniques. Six female swimmers of national level participated in the study. (Age: 19.08±2.7 years, Body weight: 61.5±4.68 Kg, Height: 1.72±0.41m). The athletes executed three trials in each technique. The best trial, for each technique, considering the horizontal take off velocity, was selected for the analysis. The results indicated that there was no difference on impulse time and take of velocity between the two techniques, while the distance of the body’s center of mass (CM), in the horizontal axis, from the edge of the starting block, during the “ready” position and the angle of attack in the water, (angle of the curve of the CM), were greater for track. The maximal acceleration of CM, during impulse phase, was higher for grab. A tendency was noticed with lower values, concerning angle of take off of the CM, for track. The form of the curve of the acceleration in the horizontal axis was different for the two techniques. Track presented higher values in the initial stage of impulse, while grab presented higher values in final stage of it. This could be an advantage for track technique as it creates the condition for more efficient impulse, though this is not confirmed from the results of the present study. The differences that were found, in the parameters between the two techniques, track and grab, indicate that track, as a relatively new technique has the potentials to become an efficient technique, if it takes some improvements, at least for a certain class of athletes and events.