To investigate the influence of alpine ski event results on the new devised performance test for alpine ski racers (call for Bosco test). Bosco test evaluates the performance in the jumping height that carries a barbell on its shoulder with weight load from 0kg to 50kg at random, and indicate counter, and it is consisted of from vertical posture to squat posture with countermovement, and jump performance, and evaluation whether performance in the jump height; experimentally. The subjects were ten male alpine ski racers. Five kind of extra load on the counter movement of jump exercise test. The analyzed mechanical parameters are on the basis of flight time (sec), peak velocity (m/sec), peak force (N), and peak power (watt). As a result of having compared it in relationship with event results, by an International Ski Federation (F.I.S. 2008 version) of point , It was recognized significantly correlated (r= -0.64~-0.75 p<0.05) between in slalom point and jump height by Bosco test and out put mechanical power. It was observed that the alpine ski giant slalom point was significantly correlated to these variable in Bosco test condition and also to jumping height of center of gravity (p<0.05) and peak power (p<0.05) in Bosco test. In conclusions , Bosco test result have suggested in that it was an effective evaluation of physical fitness index was shown as a measurement and evaluation physical fitness characteristics as ski performance event results of an Alpine ski athlete.

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Parallel turns during a descent are performed using a single ski, in which a skier raises the inner ski from the snow plane and descends on only the outer ski. When the direction of the turn changes, the skier changes from the left ski to the right ski (or vice versa) and continues to descend in a similar way. However, it has also been observed that skiers appear to descend with parallel turns using both skis. The part of changing the direction of the turns is considered to be a common element in these types of descent. To study the mechanism of changing the direction of the turns, we adopted the method used to analyze the process of a descent with step turns. Step turns, in which carving turns are changed into skidding turns, were analyzed by a three-dimentional drawing method. Similarly to the analysis of step turns, the three-dimentional drawing method was applied to the part of changing the direction of the parallel turns, and the following finding were obtained. A parallel turn during a descent involves a skidding turn using the outer ski. This skidding turn, during which the skidding of the ski gradually decreases, changes to a carving turn. At this time, the center of gravity of the skier is shifted from the left ski to the right ski (or vice versa) and at the same time, the direction of the turn also changes. This turn is a carving turn, and the carving turn changes back to a skidding turn, in which the skidding of the ski subsequently increases. According to this explanation, a descent involving turns apparently using both skis is essentially the same as a descent using only the outer ski, because the skier shifts the center of gravity from the left ski to the right (or vice versa) and at the same time, the direction of descent changes. This type of descent is similar to a descent with step turns.

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This paper proposes the analysis method for skiing turn using the systems which measure the orientation and gliding trajectory of a skier on an outside actual snowfield. The orientation measurement system that consists of 3D gyro sensor, 3-axis acceleration sensor and 3-axis magnetic field sensor provides orientation relative to the global frame and 3-axis acceleration. The trajectory measurement system that consists of GPS receiver provides gliding trajectory of skiing turn. The gliding velocity is estimated using the information from these measurement systems and Kalman filter in this analysis method. The measurement experiment has been performed to confirm the performance of proposed measurement systems. In this experiment, the orientation and trajectory measurement systems have been installed on the right foot boot and head of skier, respectively. The proposed systems have provided the rotation matrix that transforms the global frame, acceleration relative to the global frame and gliding trajectory. The analysis method has provided the gliding velocity relative to the global and local frame using information from the proposed systems. The gliding trajectory has indicated significantly different moving distance between skidding turn and carving turn. The gliding velocity relative to the local frame has indicated the different period and the effect of strike slip between skidding turn and carving turn. The results which are obtained from the proposed systems and analysis method indicated the effectiveness and the validity. The proposed method that can analyze the major features of skiing turn is able to quantitatively evaluate the skill.

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