INTRODUCTION: Deflection of the ski and the ski-snow contacting pressure are both important factors in the ski turn. But they have not been directly measured precisely in the actual turn on the snow slope. In this study, a new measuring System to detect both the ski deflection and the ski-snow contacting pressure is developed. METHOD: Deflection sensor consists of bending sensors connected in a long beam as shown in Fig.1 .The structure of the bending sensor is the cross plates with strain gauges. Commercial pressure sensors of 6mm diameter have been installed 5mm apart from the edge along the side curve as shown in Fig.2. The data logger system to collect these data has been also developed. Experiment was carried out at Shiga-kogen in Japan. RESULTS: The deflection profile obtained from the sensor beam agreed well with the bottom surface profile in the static load test. And with that measured by displacement meter in the Vibration test. Measured deflection in the snow slope showed the main change of the deflection with minor vibrating deflection. On the other hand, detected pressure by each pressure sensor showed large fluctuation even at 4ms sampling time. By averaging data in each time section, the pressure distribution along the ski and its time change could be obtained. DISCUSSION: The deflection sensor reveals the actual deflection motion during the ski turn. Pressure at each sensor must be caused by the snow crush between the ski surface and the snow surface. The deflection in the front part of the ski and the increase of the pressure must be produced by the compression or crush to the snow in making a groove on the snow surface. CONCLUSION: A new measuring System which detects both the deflection of the ski and ski-snow contacting pressure at the same time during the actual ski turn on the snow filed has been developed. It must be useful to investigate the turning mechanism at the ski-snow contact and to evaluate the ski design.
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