Abstract
To evaluate the properties of the sports surfaces, friction tests and shock attenuation tests have been generally adopted to determine the horizontal and vertical characteristics, respectively. Although the diagonal impacts are often observed in athletic sports, shock attenuation test treats only the vertical impact test. Therefore we developed a two-dimensional impact test device for examining the two-dimensional cushioning characteristics of sports surfaces in previous study. To produce a simultaneous two-dimensional force against a test specimen, we incorporated a parallelogram linkage in the measuring system. In this study, the various cushioned and non-cushioned impact tests were examined to calculate the FR(Force Reduction) values not only in vertical but also in horizontal impact force. As the results, horizontal shock attenuation characteristic was different from that of the vertical one in terms of initial angles. Additionally, the differences of relationship between the horizontal and the vertical shock attenuation were observed in specimens. This result indicates that HFR should be considered for preventing the injuries and providing the equality in regulation.
