This paper deals with the kinematics analysis for clarifying the mechanism of Ollie motions, and the motion analysis was conducted by the joint angle of snowboarder for indicating the advantage of Ollie motion in snowboarding. We used the motion sensors installing inertial sensor for measuring the motion of snowboarder. The motion sensors were attached to the body segments（upper body, lumbar, femur and lower thigh） of snowboarder. The 3D posture in local coordinate system was estimated by using the unscented Kalman filter, and the joint angles （lumber, hip and knee） was applied the inverse kinematics to the 3D posture. We conducted the motion measurement of snowboarder on the snowboard jump kicker using the motion sensors by an upper grade snowboarder and an intermediate grade snowboarder, and we analyzed by using the joint angles. These analytical results indicated the characteristics of motion by using the Ollie on the snowboard jump kicker, and the importance of Ollie motion was represented. The obtained characteristics of motion can be used for clarifying the mechanism of Ollie motion and the teaching of snowboard jump.
The purposes of this study were to develop and systematize the basis measurement technologies of the ski racing performance evaluation and support system. To perform these purposes, the parallel measurement and analysis system of the mechanical kinetic and physiological signals was developed. In this study, the vertical directional vibration of ski board and the acceleration of the orthogonality direction for major axis of ski board abstract were adopted as the mechanical kinetic measure. The ski racing technique of ski racer was evaluated by the mechanical kinetic measure. Furthermore, the ECG and EMG were adopted as the physiological measure. The physical and mental conditions were evaluated by the physiological measure. The field test was performed in actual GS (Giant Slalom) racing competition using this system. The results of this test led to conclusions as follows; the ski racing technique could be evaluated by the mechanical kinetic measure and the physical and mental conditions could be evaluated by the physiological measure.
Japan's skiing population has declined sharply over the last two decades, consequently the managements of ski fields have deteriorated and many ski fields have been temporarily or permanently closed. However, it is unclear what factors affect the closure of ski fields. In order to block the closure of ski fields and explore their survival methods, it is essential to clarify the tendency common to closed ski fields. In this study, we restricted the survey area to Nagano Prefecture, Japan and statistically compared open and closed ski fields with more than 10 factors. As a result, there were significant differences in 4 factors related to the size of ski fields. We also found that altitude differences and longest downhill distances have been correlated with skier's satisfaction for ski fields. These results suggest that the risk of closure of ski fields may be higher with smaller scale and therefore lower level of satisfaction of skiers. Interestingly, there were no significant differences in open and closed ski fields with respect to distances from interchanges and degrees of difficulty of ski slopes. These results also suggest that these two factors may be independent of the closure of ski fields. Taken together, our results may be useful for considering the survival of ski fields in Japan in the future.
In Japan, the Research on Ski Resort Development has been increasing in recent years, and its content has been improved. However, most studies concern Ski Resort Development since the 1960s, and the Characteristics before the War have not been clarified.
In this Research, we will clarify the Development of Ski Resort along the Shin-Etsu line in Nagano Prefecture between 1912 and 1938. The reason for paying attention to this district was that it was the most developed region in Japan at that time. For the material, we use the data of the Ministry of Railways in Nagano Prefecture and the data on this Ski Resort in this region.
The Results were as follows.
1. Only Iiyama and Nozawa were the Ski Resorts in the region from 1912 to 1924. The two Ski Resorts had a few Japanese Hotels and the narrow ski-slope places near the station. Ski equipment for rent was not attached.
2. The regions of the Ski Resort from 1924 to 1936 remained almost the same places as before. However, the Railroad Company and the Ski Club started to develop the Ski Resort. The position of the slopes changed from near the station to the Mountain side. Ski equipment for rent started.
3.The number of regions of the Ski Resort from 1932 to 1938 had increased more than before. The Railroad Company and the Ski Club made a special Organization to increase the Ski Visitors. The Organization started to open the ski competitions and lessons.
This study examines the developmental processes of ski resorts in the Austrian Alps, where some ski resorts have continuously developed. The development processes of Ischgl in Tyrol are analyzed by changes of facilities in the ski field and the resort town. Ischgl has a short history compared to the historical Austrian ski resorts, such as Kitzbühel and Sankt Anton am Arlberg. By connecting the ski runs with Samnaun（Switzerland）, the ski field has been enlarged and the elevation has reached 2,875 meters above sea level. The ski field facilities have frequently been renovated for the comfort of the skiers. The resort town has increased its numbers of luxury hotels, après ski pubs, and sports shops. Ischgl's continuous development relates to its increasing identity as a typical resort of après ski and music concerts. However, its enriched facilities in the large ski field with a reliable snow cover have been more important to these developments.
The aim of this study was to examine and compare the trends among skiing and snowboarding injuries. We tallied the total annual number of visitors to 3 ski areas over the past 3 years and investigated the number of persons who developed sprain, bone fracture, bruise, cut/contused wound, bone dislocation, and other injuries. We also examined the details of the individual injury types, and calculated the rate of blows to the head and the usage of helmets. As a result, it was found that the incidence of sprain was higher for skiing, and that of bone fracture and dislocation was higher for snowboarding. In skiing, sprain of the knee joint was observed most often, followed by head bruising, body trunk bruising, and bone fracture of the lower extremity, in this order. In snowboarding, bone fracture of the forearm was observed most often, followed by body trunk bruising, dislocation of the shoulder, and head bruising, in this order. The incidence of injury was higher for snowboarding compared with skiing, except for that of sprain. In skiing, sprain of the knee joint accounted for approx. 30%, which was significantly high. In addition, the overall occurrence of lower extremity injuries accounted for greater than 50%. In snowboarding, the incidence of injury of the upper arm and head was high. Although the incidence of head impacts was similar between skiing and snowboarding, the usage of helmets was significantly lower in snowboarders. Since head blows could cause serious injuries, one of the future tasks for injury prevention will be to increase the usage of helmets.
In this study, we clarified the level of mental health of elderly people participating in Masters Ski（MS）, and examined the relationship between MS activity status and reason for participation in MS. The target was 717 MS participants registered in the Ski Association of Japan and an anonymous self-administered questionnaire survey was conducted. Of the 453 people（collection rate 63.2%） who responded, 352 did so（responsive response rate 49.1%） without any defect in response; were analyzed from 124 subjects over 65 years old. Results revealed that the proportion of those with good mental health was significantly higher among young-older MS participants than the general population. In addition, the factor related to mental health was “the Self-rated Health” and the reason for implementation was “to participate in the competition and games.” In other words, the risk of poor mental health was low in those who had a high Self-rated Health and those who cited “to participate in competition or games” as the reason for implementation. From the above, it was found that the mental health of young-old participating in Masters Skiing is better than that of the general population, and the tendency to participate in the event and the level of the Self-rated Health could be factors that increase mental health.
Cork720 is a Ski Slopestyle jump trick, in which a skier's body rotates around an axis that is tilted away from the vertical and horizontal axis. The purpose of this study was to analyze the takeoff characteristics of the Cork720 of a Japanese top skier by comparing with the Upright 720 which rotates around the vertical axis. The subject was 1 top level male Ski Slopestyle athlete belonging to the Japanese national team（ age: 20years, height: 168cm, weight: 64kg）. Data were collected at a waterramp which is a typical off-season training facility for Freestyle ski. Two high speed video cameras were used to film from both sides of the jump and the three-dimensional（3-D） coordinate values were calculated by using the DLT method. Angles of the backward and sideward tilt of the body, the joint angles of the knees and hips, shoulder and hip rotation angles were analyzed. It was found that the takeoff motions of the Upright720 and Cork720 were similar, though Cork720 had larger back tilt of the body, the extension of the right knee and hip was larger, and the shoulder and hip started to rotate earlier. The side tilt of the body was thought to be the main factor to create the tilted axis of Cork720, and also would be the greatest difference between the two tricks, but in this case, it resulted that the side tilt of the body was almost the same. From these results, it was suggested that in this case, the tilted axis of the Cork720 was made by the back tilt of the body and the extension of the right knee joint and the right hip joint.
There are many situations that the difference between imagery（subjective） and actual（objective） movements occurs in skiing. In traditionally utilized feedback method with video, it is impossible to get real time visual feedback. In the present study, we developed the system for real-time visual feedback during skiing, and evaluated the availability of the system. The movie captured by a video-operator who followed a subject was projected in online through the smartglass that the subjects wore. Sixteen skiers and snowboarders with various skill levels tried this system.We interviewed subjects immediately after the trial.Their impression was that getting real-time visual feedback of their own motion utilizing the present system, which helped them modify their performance in middle and high level subjects. However, beginner subjects could not afford to use the feedback information. Since the present system had unavoidable time-delay of 186 ms, it was suggested that it is not suitable for learning short turn. Therefore, the present examination suggested that this real-time visual feedback system can be effective in learning long turn for middle and high level skier who have clear goal images of their performance.