Muscle cross-sectional area by magnetic resonance imaging, and muscle strength, were measured in the alpine skier into elite alpine skier group (Elite ALP) and non elite alpine skier group (ALP) to evaluate the muscle morphological and functional characteristics compared with healthy man group (CONT). In muscle cross-sectional area of quadriceps and hamstrings were not statistically significant differences at 70, 50, 30％, position. Isokinetics strength of knee extention and flexion were measured at 30, 90 and 180 degree per second. There was statistically significant high difference in control group at 90 and 180 degree per second (p<0.05). Furthermore, calculated to strength torque per unit muscle Cross-Sectional area (peak torque / muscle Cross-Sectional area: call for specific tension) 30, 50, 70％ position at knee extension by 180 degree per second. Specific tension was significantly higher Elite ALP than CONT by 50％ position (p<0.05). In addition, specific tension were higher Elite ALP and ALP than CONT by 70％ position (p<0.05). However, there was significant difference in Elite ALP and ALP about specific tension. In conclusion, there were no significant difference of the among three groups by the muscle cross-sectional area in each position. However, alpine ski racer’s muscle functional characteristic was admitted in specific tension in a high-velocity range of motion. It might be a result of the origin as this factor from the development of the muscle fiber area by the muscle fiber composition and described as a neural factor.

View full abstract

A skier turns with a traverse posture in which the outside ski trails the inside one. However, in contrast, a telemarker turns with a telemark posture in which the inside ski trails the outside ski. At the same time, the heel of a telemarker on the inside ski is lifted up from the ski surface. What requires further explanation is how and in what order the telemarker enables heel-freedom, performs edging and modifies the edging of the skis during performance of turns. We developed a combined model capable of both flexion and extension of the hip joints with an inner rotation of both femurs that can turn like a telemarker. The knee joints and ankle joints were fixed. From a straight down-hill running posture, if the bilateral hip joints around the model's femur axes are rotated inside, it can attain a wedge posture. Then from this wedge posture, by flexion (forward) of the left hip joint and extension (backward) of the right hip joint (or vice versa, i.e., flexion of the right hip joint and extension of the left hip joint), it can achieve a heel-free posture. One servomotor was attached to the flexion and extension of hip joints. This model slightly inclines to the heel-free side and the inside ski runs behind the outside ski. This model can perform a telemark skiing technique, such as wedge turn with heel-freedom by flexion and extension of the hip joints from the wedge posture.

View full abstract

The purpose of this study is, by focusing on what parents with primary school children expect from the effects of skiing and the ski schools and by clarifying this point, to investigate whether the ski schools have been able to fulfill the expectations of the parents. In order to achieve this purpose, this report illuminates the expectations of the parents towards the effects of skiing, the expectations for the ski schools, the awareness of ski schools toward the expectations of parents and the readiness of the ski schools. Parents who send their children to a sports club in Tokyo, primary school in Ibaraki prefecture, Gunma prefecture and Osaka (1082 parents) and ski schools across the country (42 schools) are the subject of this study. The result of the study is as follows. 1) Expectations of the parents towards the effect of skiing is high regarding an experience in nature, improvements in physical abilities and an experience one can only obtain by skiing. 2) Expectations of the parents for the ski schools is high regarding expectations for custom-made guidance fit for the child, a low budget child-price and an environment suitable for the child. 3) Awareness of ski schools is low compared to the expectation of the parents regarding the expectations for an experience in nature. 4) Awareness of ski schools is low compared to the expectation of the parents regarding the expectations for a program full of adventurous experiences and children’s activities without their parents. 5) Awareness of ski schools is high compared to the expectations of the parents regarding expectations toward service for parents.

View full abstract

This paper proposes a measurement system and analysis method to reveal characteristics of snowboard turn. This measurement system that consists of 3D gyro sensor, 3-axis acceleration sensor, 3-axis magnetic direction sensor and PIC microcomputer is able to measure angular velocity, acceleration and magnetic field through the digital communication. We can simply perform the experiment because this system is directly attached to the binding on snowboard, even if a measurement range is very large like skiing ground. The analysis method provides initial condition (slope) from gravity acceleration, edging angle from angular velocity and gliding state (direction angle) from magnetic field. As a result of experimental trial on the carving turn by the snowboarder in a skiing ground, we could obtain the gliding information quantitatively. Furthermore, this proposed system could catch a personal habit such as the difference of edging angle in the front side turn and back side turn because edging angle and gliding state indicate the characteristic of the snowboard turn at length. Therefore, we can prove the effectiveness and the validity of this proposed system. This measurement system can analyze the major features of snowboard turn and this analysis method may be able to quantitatively evaluate the skill of snowboarders.

View full abstract

A ski slides on a (snow) slope with an inclination angle of α. The ski has an edging angle of β. Namely, β is the angle of the ski relative to the slope. The angle between the longitudinal direction of the ski and the fall line FL is defined as the ski angle δ. The angle between the tangential direction of the locus of the sliding ski and FL is denoted as θ. Therefore, a ski sliding on a slope involes the angle α,β,δ, and θ. α is measured using an angle gauge on a ski slope. The horizontal edging angle β0 is also mearsured using an angle gauge on the track of the sliding ski on snow. θ is obtained by drawing a diagram of a sliding ski. The transversal inclination angle β1 is calculated using α and θ. β is given as β=β0+β1. A sliding ski with θ equal to δ is defined as undergoing a carving turn. We developed a method of three-dimentionally determining and drawing the state of a sliding ski during carving turns on the basis of the measured values of α,β, and θ. By this method, it is possible to three-dimentionally draw the state of a sliding ski viewed from the front of the ski (or from an arbitrary direction) on paper. This means that we can directly observe the edging of a ski sliding on a (snow) slope. This visual observation is very important in the study of skiing motion.

View full abstract