Mechanical caracteristics of tatamis used in judo

Abstract

Mechanical caracteristics of tatamis used in judo The purpose of this study was to evaluate physical and mechanical characteristics of different tatamis. It is important to determine the desirable characteristics of tatamis to enhance judo wrestlers safety due to frequent falls on the tatami. Seven tatami types were intentionally selected six of synthetic material and one of straw. A ballistic pendulum connected to an accelerometer was used to measure their physical characteristics. The data were analyzed by descriptive and inferential statistics, analyses of variance with Tukey multiple comparison test and Pearson.s correlation analysis with significant level established at 0.05. The results showed: a) a high coefficient of restitution (CR) of the tatamis with average about 0.60; b) the highest impact value transmitted by the pendulum tatami interaction was found in tatami type "C" (36.54 g) and the lowest in tatami type "F" (24.24 g) and c) a high negative correlation between CR and impact (r = - 0.80). These results allowed us to recommend the tatamis type "A" and "F" for judo practice and to suggest other studies, taking into consideration a greater number of variables, such as: chemical analyses of the materials used to make tatamis, the density and the resilient.