This paper proposes an estimation method of acceleration components using GPS receiver and inertial and magnetic field sensors for ski turns analysis. This method estimates the centrifugal acceleration, the tangential acceleration, and the Coriolis acceleration. The carving turns are used the ski deflection and the ski side curve for the rotational motion, and the skidding turns are conducted the speed control by the side skidding. These phenomena can represent the rotational components of acceleration. We conducted the measurement experiment in the carving and skidding turns by a skier. The acceleration components were estimated in the carving and skidding turns, and we analyzed the characteristics of turns. The analytical results indicated the increase of centrifugal acceleration in the carving turns, the decrease of centrifugal acceleration by the side skidding in skidding turns, and the generation of Coriolis acceleration for the decrease of friction force in the second half of the carving turns. These analytical results could indicate the effectiveness of proposed method. The proposed method can be used to analyze more detailed features of skiing turn than previous studies, and this method is able to evaluate the skill quantitatively.

View full abstract

　This study modifies the field test items developed and examined by the authors in 2019 to measure the physical fitness of junior menʼs alpine skiers, increases the number of participant, and targets high school male alpine skiers of a wide range of competition levels. The purpose was to clarify the relationship between field test items and competition results. The participant were 50 high school male alpine skiers who belong to the Ski Association of Japan. The physical fitness test was conducted in October 2020. The points issued by the International Ski federation and the Ski Association of Japan are GS and SL as indicators of competition results（2020/2021 FIS NO.21/SAJ NO.17）. In order to clarify the relationship between each field test item and the competition results, we examined using Pearson's product moment correlation coefficient and set the significance level to less than 5%. As a result, standing long jump, one-leg standing long jump（right / left）, standing 5-step jump, sit up, figure 8 running, 20 cm jump, hop test（both legs / right / left）, standing body forward bending, 4.5 cm eye-opening one-leg standing test（right / left）, high box jump 90s, and 12-minute running.

View full abstract

　This study aimed to examine the situation of ski clubs in junior high schools and high schools with a transition to the local communities of club activities, and organize issues related to the transition to the local communities of ski club activities. The research method was based on data published by the Japan Junior High School Physical Culture Association, All-Japan High School Athletic Federation, and Ski Association of Japan, to determine annual changes in junior high school and high school ski club students. The percentages of public and private schools participating in the 59th All-Japan Junior High School Ski Competition and the 71st All-Japan High School Ski Competition held in the 2021/2022 season were also investigated. The results showed that the number of junior high school and high school students who were members of ski clubs, and the number of students registered with the Ski Association of Japan showed a significant downward trend. The ratio of public schools to private schools in the All-Japan Junior High School Ski Championships and All-Japan High School Ski Championships showed that private schools tended to have more athletes in the Southern Kanto and Kinki regions, suggesting that the economic situation of families in urban areas has an impact on the number of athletes. As for the transition to the local communities of ski club activities, there are few obstacles to the transition of junior high school ski club activities because Alpine ski coaching for junior high school students is provided by local clubs, youth sports teams, prefectural ski federations, and professional coaches. However, the following issues were identified during the transition to local communities: “club management funds,” “securing and training instructors,” “improving instructorsʼ treatment,” and “ensuring a continuous environment for activities.”

View full abstract