Abstract
Shock attenuation property of sports surfaces is especially important not only for the athlete’s performance but also for injury prevention. To evaluate the properties of the sports surfaces, some sports governing bodies often adopt friction tests and shock attenuation tests to determine the horizontal and vertical characteristics, respectively. Although the diagonal impacts are often observed in athletic sports, shock attenuation test only treats the vertical impact test. Therefore we developed a two-dimensional impact test device for examining the two-dimensional cushioning characteristics of sports surfaces in this studies. To produce a simultaneous two-dimensional force against a test specimen, we incorporated a parallelogram linkage in the measuring system. The impact force generated was measured by the load cell. And an accelerometer was attached and the acceleration was also calculated. And experiments were performed to three kinds of different samples. In order to confirm the characteristics of the surface, the relationship between vertical and horizontal maximum force and displacement was confirmed. As the results, Hysteresis property in the vertical direction was found to depend on the hardness of the sports surfaces. However, it was found that the property in the horizontal direction is more complex than the vertical direction.
