Biomechanical Analysis of Body Movement During Skiing Over Bumps

Maintenance of balance of the skier's body is one of the most important and basic techniques in skiing on slopes of various conditions. However, skiers, especially beginners are likely to lose their balance on an uneven terrain with dips and swells. In order to keep his balance during skiing on an uneven terrain, it seems to be important for a skier to avoid receiving impulse from the snow surface. Some investigations have been conducted about maintenance of balance of body during skiing over artificially constructed bumps by means of electromyography (Miyashita and Sakurai, 1979), electrogoniometry (Iizuka and Miyashita, 1979) and cinematography (Miyashita and Sakurai, 1979, Iizuka and Miyashita, 1979, Sodeyama et al., 1979 and Ikegami et al. 1985). However, there is no research to try to measure force or acceleration acting on the skier's body during running over bumps. Therefore the purpose of this study is to measure force acting on skier's body by analyzing the movement of skier's body mechanically as well as kinematically, and to find out essential motions to maintain the balance of skier's body against rapid change of force acting from snow surface while skiing over bumps on a straight downhill run

A Three-Dimensional Cinematographic Analysis of Badminton Strokes

Badminton and tennis are two of the most popular striking activities, Broer & Zernicke (1979) stated that one evident difference between the two sports skills was the degree to which the wrist snap was used. They stated that the wrist snap just before impact was the most essential action of badminton strokes and it was enabled by the lightness of the badminton racket. Gowitzke & Waddell (1979) analyzed forehand and backhand smash strokes, representative of the most powerful overhead striking motions in badminton. They concluded that medial rotation of the humerus at the shoulder joint and pronation of the forearm at the radio-ulnar joints were the principal contributing movements for the forehand smash, In badminton strokes, many joint actions in three planes are involved in the striking motion, so that two-dimensional procedures are insufficient for analyzing the stroke motion of badminton. Relatively small numbers of biomechanical studies have been completed on kinematic parameters of badminton strokes. Quantitative studies with threedimensional procedures have been even more limited. The purpose of this investigation was to determine the changes of joint angles of the upper body during the execution of the drop shot and the cut shot in badminton using three dimensional cinematography

A THREE-DIMENSIONAL CINEMATOGRAPHIC ANALYSIS OF THE BASEBALL PITCH

Pitching is one of the most important aspects of the game of baseball. However, only a small number of quantitative biomechanical studies have been reported (Feltner & Dapena, 1986). Specifically, there have been few studies of the motion of the forearm and wrist joints during a pitching action. The purpose of this study is to record the changes in angles and angular velocities of the shoulder, elbow, radioulnar and wrist joints during a baseball pitch. In this study, three dimensional (3-D) high-speed cinematography was used to record the fastball pitches of varsity baseball pitchers

Observation of the decay mode K_L -> pi^+ pi^- e^+ e^-

We report on results of an experimental search for the K_L -> pi^+ pi^- e^+ e^- decay mode. We found 13.5 +- 4.0 events and determined its branching ratio to be (4.4 +- 1.3(stat) +- 0.5(syst))*10^{-7}. The result agrees well with the theoretical prediction.Comment: 9 pages, 6 eps-figures, LaTeX2e, graphicx package, submitted to Physics Letters

Scalability of spin FPGA: A Reconfigurable Architecture based on spin MOSFET

Scalability of Field Programmable Gate Array (FPGA) using spin MOSFET (spin FPGA) with magnetocurrent (MC) ratio in the range of 100% to 1000% is discussed for the first time. Area and speed of million-gate spin FPGA are numerically benchmarked with CMOS FPGA for 22nm, 32nm and 45nm technologies including 20% transistor size variation. We show that area is reduced and speed is increased in spin FPGA owing to the nonvolatile memory function of spin MOSFET.Comment: 3 pages, 7 figure

The Changes in Mechanical Energy During the Giant Swing Backward on the Horizontal Bar

In the giant swing backward, mechanical energy of the whole body is decreased due to friction between gymnast hands and the bar, and to air resistance. To complete the rotation, the gymnast has to do muscular work to offset these energy losses. Total mechanical energy changes with the relationship between energy loss and muscular work. Therefore, for biomechanical investigation of the giant swing backward, it is important to have an accurate measure of the mechanical energy changes of the whole body. Although there are many studies of energetics of the human fundamental movement such as walking and running, the mechanical energy changes of the whole body have not been reported during the giant swing backward on the horizontal bar. The purpose of this study is to report the mechanical energy changes of the whole body, and to identify the muscular work donc by the gymnast during the giant swing backward on the horizontal bar

JUMP HEIGHT IN LADIES SINGLE FIGURE SKATING IN THE 18TH WINTER OLYMPIC GAMES IN NAGANO 1998

As a part of the IOC Olympic Biomechanics Research Projects conducted at the 1998 Nagano Olympic Winter Games, jump height was examined for the free program session of ladies single figure skating. Jump height varied according to the number of rotations and the type of jump. Jumps using toe-picks, such as Lutz, Flip and Toe-Loop tended to be higher than jumps involving a swinging free leg style such as the Axel, Loop and Salchow. There was no remarkable difference for the maximum jumping height among groups with different competition ranking. Though jump height tended to decrease in the latter half of the performance, the decrease was smaller in skaters with a higher standing in the competition