INTRODUCTION: The underwater gliding motion during start and turn phases are important for the total race time in modern swimming [1]. The purpose of this study was to analyze the underwater gliding motion in collegiate competitive swimmer. METHODS: Twelve healthy male collegiate swimmers volunteered to participate in this study. The subjects performed underwater gliding motion as fast as possible after the start wall kicking. During the underwater gliding motion, the swimmers were to hold the streamlined position. The subjects were monitored with an underwater video camera (SK-2130, SONY, Japan) with a sampling frequency of 60Hz in the sagittal plane to measure the angular displacement of their different joints. In this study, the subjects were asked to wear two different models of swimsuits: one is made of the conventional fabrics; the other is a newly developed, so-called high speed swimsuit (Fastskin LZR racer, Speedo, England). RESULTS: The swimming velocity of the subjects wearing a conventional swimsuit decreased when the flexion-extension movement in the knee and the hip joints were performed during underwater gliding motion. On the other hand, the swimming velocity of those wearing an LZR swimsuit showed that the highest speed was maintained during the gliding motion when the knee and the hip joint angles of 180 degrees were maintained from the start to 0.8sec. DISCUSSION: During the underwater gliding motion, the swimmers have to hold a streamlined posture. To stay in the best streamlined position, and to minimize the hydrodynamic resistance, the return to the water surface should rather be initialized by a progressive and synchronize action of the three joints [2]. The result of this study was that the highest speed was maintained during the gliding motion when the knee and the hip joint angles of 180 degrees were maintained from the start to 0.8sec. In other words, during the underwater phase such as a start and a turn, it was clearly important that the swimmer maintained his body in a streamline posture.
© Copyright 2010 Biomechanics and Medicine in Swimming XI. Published by Norwegian School of Sport Sciences. All rights reserved.