This paper provides fundamental features of representative analytical techniques, such as kinematics, kinetics, dynamics contribution analysis and simulation, for evaluating sports motions. The first one of the techniques is kinematics analysis which is a fundamental method to quantify geometric parameters, such as position, velocity, angular displacement and velocities of body parts and joints. The second one is kinetic analysis which quantifies kinetic parameters such as joint torques and joint forces by using equation of individual segment motions. The third one is dynamics contribution analysis which obtains relative contributions of joint torques to the generation of evaluation parameters, such as whole-body eg acceleration, segment velocities, by using analytical form of the equation of motion of the target system. The last one is simulation which obtains virtual motion data outputs through time integration of the equation of motion of the target system with joint torque inputs.

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This paper proposes the method to estimate the 3D posture of body segment using inertial and magnetic field sensors. The measurement system in this study that consists of 3-axis gyro sensor, 3-axis accelerometer, and 3-axis magnetic field sensor measures 3-axis angular velocity and 3-axis acceleration and 3-axis magnetic field. The sensor fusion compensates drift error of gyro sensor output and the error of rotational components of acceleration (centrifugal and tangential accelerations) of accelerometer output, and it estimates the 3D posture (Roll-Pitch-Yaw angle) of multiple link in global coordinate by applying to Extended Kalman filter. The measurement experiment was conducted to indicate the accuracy of the proposed method using experimental setup installing rotary encoders. The 3D posture estimated by the proposed method corresponded with the 3D posture obtained by rotary encoders. This result indicates that drift error of gyro sensor and the error of rotational components of acceleration are compensated. Therefore, the effectiveness of the proposed method was indicated and the proposed method can be used to the measurement of motion generating rotational components of acceleration of multiple link .

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As hitting topspin ball has been becoming popular, precise researches of friction between the string-bed and ball were carried out. But there were not much researches of human body or technique. The aim of this study is to make the measurement system to clarify the technique of swinging a racket. That swing path must be different by the grip angle. If the correct grip angle becomes clear, players will be able to acquire the swing technique quickly without the injury of wrist. First, it is necessary to know overall movement of hand, forearm and racket. By using strain gauges, we measured the force that occurs on the string-bed, and the strain that appeared on the racket throat. From inertial sensor attached on hand and forearm, we measured the acceleration and angular velocity of them. From this experiment, we found these data are useful for analyzing the swinging technique.

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Forearm passing is used in serve receive, passing free or down balls, setting, and floor defense. A player adjusts the direction of the ball and a distance to the target by changing the power to add to the ball and the inclination of the arm. A player must accelerate a ball when playing free ball, on the other hand, a player must absorb the ball's momentum when playing a hard driven spiked ball. We try to know how skilled player absorb the ball's momentum, how skilled player control the ball direction? Why unskilled player cannot control the ball well? This time, we use the wireless motion sensor (Logical product). It doesn't stress on subject, no cable needs.

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A major challenge in the successful transfer of technology to sports and in particular swimming is taking scientific measures and translating them into terms suitable for the serious swimmer. Our work with inertial sensors has demonstrated that the measures can obtained elite level instrumented pool variables from a single wearable sensor. This paper introduces visualization methods in order for coaches and athletes to use often complicated technical data. Options currently at hand are various 2D plots and a small number of 3D options.

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Objective: To develop a system capable of measuring the impact forces of side steps and tackles in rugby football using inertia and gyroscope sensors. Design: Coordinate transformation using the rotary matrix and calculation of velocity and position using integral calculus. Methods: The skills of side stepping and tackling were carried out using students (aged 18-20 years) from Kosen technical college. Small sensors were attached to each player. The acceleration vector of a local coordinate detected by a sensor was converted into the acceleration vector of the absolute coordinate. In the process, the calibration of acceleration, the velocity calculation by the integral calculus, the span error correction of velocity, the displacement calculation by the integral calculus and the span error correction of position were also recorded. Fundamental experiments and practical experiments were carried out in the above-mentioned procedure. Results: We first dropped a ball (160 g in weight, 95 mm in diameter) from a height of 1 m; the measurement system was capable of measuring impact forces with approximately 8 % of precision. Patterns of side steps and tackles were also identifiable. Conclusions: The actual displacement is in agreement with the qualitative measured result, but did not agree quantitatively. In the 1-on-1 tackle, the impact force value of the defender was 4.15 G, while the attack was 3.45 G. Calculating integral calculus using acceleration sensors offers superiority over global positioning system technology for the measurement of impact forces in rugby football.

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Recently, tight wears to compress human-body by well stretched fabrics have been applied to the competitive-sports and medical treatments. Those clothes are consisted of the woven and knitted fabric materials. The fabric materials have specific properties to be elastic in large deformation region. Moreover, the woven fabric shows anisotropic characteristics that depend on the direction of fiber families. Therefore, in this study, we propose a pressure prediction method for sportswears. For the experimental study, triathlon-wears were applied to biomechanical observation and tensile loading tests. First, to obtain stretch of the wear, geometrical size of human body in cycling pedaling was observed by high-speed camera. Next, in material tests, uniaxial loading test by fabric specimen of triathlon wear were conducted to obtain the relationships between uniaxial tensile stretch and stress. Besides, we assessed stiffness reduction of the materials on the assumption of use in the competition. Finally, we compared estimated value to measured value generated by the wear and showed the effectiveness of the method.

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We fabricated the 3-axis force sensor applicable to gait analysis. The 3-axis force sensor was fabricated by MEMS (Micro Electro Mechanical Systems) process. Its size was 8 mm x 8 mm * 5 mm and its weight was 0.6 g. The sensor was attached to the sole of the left foot. The sensor's size and weight were so small that it didn't interfere with human locomotion. Using this sensor, regional plantar 3-axis forces were measured during level walking on inside floor. From this measurement, peak values of forces experienced under third metatarsal were revealed; the peak value of vertical force was about 200N and that of antero-posterior shear force was about 90 N.

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An advent of a synthetic shuttlecock contributes greatly to a badminton game because of a cheap and stable supply of shuttlecock. Since the synthetic shuttlecock must be produced as same as a natural feather shuttlecock, the difference between synthetic and feather shuttlecocks must be checked. A computer simulation based on proper aerodynamic properties is a best tool to investigate this difference. This paper describes a measuring method of shuttlecock aerodynamic properties using images of shuttlecock trajectory experiment captured by a high speed video camera without a wind tunnel experiment. Through the coincidence between experimental and simulated trajectory results, the drag, lift and pitching moment coefficients and damping factor were identified with a fair accuracy. The obtained data are verified through the comparison between experimental and simulated results of other trajectory experiment. The difference of predicted trajectories between feather and synthetic shuttlecocks were discussed for four common badminton shots.

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Badminton is a high-drag game, and thus, the sport has been a subject of research from the point of view of aerodynamics. A badminton shuttlecock generates significant aerodynamic drag and has a complex flight trajectory. The primary objectives of this study were to measure the aerodynamic properties of feather shuttlecocks under a wide range of wind speeds and pitch angles. In particular, measurements of aerodynamic forces were performed at high Reynolds numbers, and the effect of spin rotation of the shuttlecock on aerodynamic properties was also investigated. The lift and drag characteristics of shuttlecock have the same tendency with and without spin rotation. On the other hand, the pitching moment coefficient is affected by spin rotation. The pitching moment for a rotating shuttlecock is larger than that for a non-rotating shuttlecock, and that the pitching moment increases with an increase in the angle of attack. A shuttlecock is aerodynamically stable, and this aerodynamic stability is promoted by spin rotation.

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The purpose of this study was to investigate the relationship between the flight trajectory of the ball and ball spin in various kinds of baseball pitch. Each subject thrown various kinds of their own pitches for three throws each. The pitched balls were recorded using 4 high-speed video cameras. The flight trajectory, ball spin rate, and direction of spin axis were obtained from the video images, and hypothetical flight trajectory with free fall was calculated from ball initial velocity. Equations were obtained to estimate the displacement of the flight trajectory from that of the free fall ball using "decomposed spin parameter" which consists of the ball spin rate, direction of spin axis, and initial velocity (p<0.001). The findings showed that the displacement of the flight trajectory depended on the ball spin rate and direction of spin axis, thereby accurately predictable from the spin. The characteristics of ball spin can be utilized to develop a strategy to alter the flight trajectory.

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It is said that rubber-ball baseball is lower score game than baseball. The reason is that coefficient restitution of rubber-ball is smaller than that of baseball ball. One more factor is aerodynamic characteristics. Therefore, in this study rubber-ball and baseball ball was rotated highly and measured aerodynamic forces in the similar real flight situation. We analyzed flight trajectory of rubber-ball and baseball ball in cases of pitching and batting by using measured aerodynamic forces. It is found that coefficient of lift and coefficient of drag of rubber-ball are smaller than those of baseball ball. Therefore trajectory of rubber-ball is lower than that of baseball ball. Moreover batting distance in one case that gets home-run distance of rubber-ball is smaller than baseball ball. It is caused by lower coefficient of lift of rubber-ball.

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This paper investigates a new constitutive model of the competitive swimwear considering stress-softening. The fabrics for competitive swimwear show nonlinear elasticity regarded as hyperelasticity and they have an anisotropic characteristic which is dependent on the directions of warp and weft yarn. In order to reproduce these properties numerically, hyperelastic model considering anisotropy was produced. In addition, they present a loss of stiffness after first loading of cycle loading test. This phenomenon depended on the maximum deformation previously reached in the history of the material. A stress-softening model using softening ratio of stiffness was proposed. Cyclic loading tests were conducted and the applicability of the model was verified.

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The purpose of this study is development of a new design method for competitive swimwear by numerical simulation. Biaxial tensile loading tests were conducted to obtain the mechanical characteristics of competitive swimwear. The fabrics of competitive swimwear consist of chemical fiber. From biaxial tensile loading test results, the fabric has anisotropy and the stiffness of the fabric shows hardening along with the increase of stretch. An anisotropic hyperelastic model was applied to the reproduction of mechanical characteristics of swimwear. Finite element simulation of tensile loading tests was conducted to show the applicability of the anisotropic hyperelastic model to competitive swimwear. The results of the simulation showed good agreement with that of tensile loading test. FE simulation of the pressure using a cylinder model was conducted to show the applicability of our design method to competitive swimwear. The results of the simulation showed good agreement with that of pressure test in a design range of competitive swimwear. Finally, new design method using a displacement field of CG model was proposed.

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Rhythmic motions of animals, such as walking and running, are generated and controlled by central pattern generator (CPG) in the spinal cord. We focused on swimming as one of rhythmic motions of human, supposing that swimming motion is generated by CPG. We constructed a CPG model with neural oscillators proposed by Matsuoka and generated the motor pattern of arms and legs in the crawl stroke with the model. First, we generated joint trajectories of the legs with outputs from neural oscillators by coordinating the parameters and coupling pattern of the neural oscillators. Next, we generated the motor pattern of the arms which coordinates that of the legs by coupling the neural oscillators of the arms with those of the legs. We confirmed that the generated motor patterns realized the crawl stroke by simulation. It was found that the motor pattern of the arms conceitedly changes according to the change of the cycle of the flutter kick.

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The purpose of this study was to propose a new methodology for the automatic identification and the classification of the swimmers' kinematical information during the interval trainig on competitive swimming. Forty-seven college swimmers attached the newly developed chest band sensor unit, which has a triple-axes accelerometer and then performed a controlled interval training set with four stroke styles. The author identified swimmer's states, such as the swimming/rest phases and the start, turn and goal touch instants by using the Ay acceleration. With the inductive inference based on the experimental results and the deductive inference based on the empirical rule on the interval training brought the estimation of the swimming time. As for the classification of the swimming strokes, extracted swimming phase signal, the mean, variance and skewness of each axis acceleration were calculated for each bout. The authors compared some of data mining algorithms for the stroke style classification with four descriptive statistics, such as Var(Ax), Skewness(Ay), Mean(Az), Skewness(Az) as the independent variables and stroke style as the depending variable. The accuracy of the stroke style classification by both the multi-layered neural network and the C4.5 decision tree were 91.1%.

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Since paddling motion in a single kayak is a combination of human body and fluid forces acting on kayak and paddle, its dynamics is complicated. Therefore, there has been no method to analyze dynamics of paddling motion considering the fluid forces. The objective of this study was to develop the simulation model of paddling motion in a single kayak and to conduct simulation analysis using this model. For this objective, we constructed the simulation model and conducted an experiment to obtain the data of paddling motion. We calculated the joint motion data from the experiment, input it into the simulation model, and compared the images of joint motion in the simulation model to those of the experiment

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Two support-interference-free measurements of aerodynamic forces exerted on an archery arrow (A/C/E) are described. The first measurement is conducted in a wind tunnel with JAXA's 60 cm Magnetic Suspension and Balance System (MSBS). The boundary layer of the arrow remains laminar in the measured Re number range (4.0 x 10^3 < Re < 1.5 x 10^4), and the drag coefficient is about 1.5 for Re > 1.0 x 10^4. The second measurement is performed by a free flight experiment. Using two high-speed video cameras, we record the trajectory of an archery arrow and analyze its velocity decay rate, from which the drag coefficient is determined. In order to investigate Re number dependence of the drag coefficient in a wider range (9.0 x 10^3 < Re < 2.4 x 10^4), we have developed an arrow-shooting system using compressed air as a power source. We attach two points (piles) of different type (streamlined and bullet) to the arrow-head and two kinds of vanes ('SPIN-WING-VANE' and 'GAS PRO') to the arrow-tail. The boundary layer is laminar for any combination, if Re is less than about 1.2 x 10^4. It becomes turbulent for Re larger than 1.2 x 10^4 and the drag coefficient increases to about 2.6, when the bullet point and 'SPIN-WING-VANE' are attached. In the same Re range, two values of drag coefficient are found for the streamlined point, of which the lower value is about 1.6 (laminar boundary layer) and the larger value is about 2.6 (turbulent boundary layer). In contrast, for 'GAS PRO' vanes, the boundary layer remains laminar at any Re considered. These findings confirm that both the point- and vane-shapes have a crucial influence on the laminar to turbulent transition of the boundary layer.

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A flying disc can fly through the air because of the combination of the lift and drag forces by the oncoming air flow. Actual fight conditions were confirmed to perform the wind tunnel experiment beforehand. In order to clarify the mechanism of flight of flying discs, the flow field structure and the fluid force were investigated on non-spinning and spinning conditions. In the fluid force measurement, lift and drag forces were taken by varying wind speeds, spin speeds, and angle of attack. Drag and lift forces were found to increase as spin increased. The angle of attack on the maximum range of lift-drag ratio or glide ratio was found to be wide from 6 to 13 degrees which was suitable for a long distance throwing. Using a smoke wind tunnel, flow visualization around the disc was performed in order to understand the effect of disc spin. It was found that spin enhances lift force by attracting the Coanda effect on the trailing edge.

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In a long-distance bicycle road game, in order to make the main rider win, an entire team makes a formation and assigns the main rider in an advantageous position for less drag. This study verified the effects from the formation consisted of multiple riders, usually called "train," with replicas aerodynamically. Four replicas were used as a train in drag force measurement and flow visualization. Bicycle replicas were fixed onto a ground plate, and the spacing of each replica was kept constant. Drag force of each replica was measured with three component load cell. Flow visualization in a smoke wind tunnel was also carried out in a horizontal plane at the riders' height. Several train formations expected to reduce drag including crosswinds were attempted. As a result, the least drag on the replica of the main rider was obtained when it was placed at the end of the train in a linear arrangement. The results of the flow visualization also explain these phenomena well.

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The paper deals with drag force acting on each cycle road racer in a cycle train. The drag force by the air is much larger than the friction force in a cycle road race and the evaluation of the drag force is important in working out the race strategy. In the experiment, a road racer was simulated by a sphere of 20 mm diameter, and the drag force on the sphere and the flow fields around it were measured at a test section in a passing water tank. The drag force was smallest at the fourth sphere in a line of 5 spheres. The effect of the line number was also shown. Because the Reynolds number of the sphere in the experiment is much smaller than that of the cycle road racer, the tendency of drag force in high Reynolds number was estimated by numerical calculation.

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Human musculoskeletal system in the upper limbs, which consists of antagonistic pair of mono-articular muscle and bi-articular muscle, is a redundant system. Therefore, great numbers of combinations of the muscle activity level are avail- able during upper limbs movement in the muscle recruitment strategy. In this paper, we derived the preferred directions (PD) that lead to maximal EMG activity from the torque plain (Te. Ts) between the elbow torque and the shoulder torque, and revealed the strategy of muscle recruitment. Finally, we simulated the muscle activity pattern from the elbow torque and the shoulder torque using PD during reaching movement and compared with actual electromyography (EMG). The simulation results indicated that muscle recruitment pattern was different depended on directions of reaching motion.

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The aim of this study was to investigate the relationships between the foot grip strength and various physical performances in adolescence. Eighty-two boys (height: 1.69 ± 0.06 m; body mass: 59.2 ±10.1 kg; BMI: 20.6 ± 3.9; mean length of both feet: 0.252 ± 0.009 m) aged 14-16 years in junior high school were participated in this study. Foot grip strength significantly correlated to hand grip strength (r = 0.56), sit up (r = 0.25), side step (r = 0.52), 50 m sprint (r = -0.37), standing long jump (r = 0.46) and handball throw (r = 0.50). Furthermore, foot grip strength more strongly correlated to side step and handball throwing, comparing to hand grip strength. These results suggest that foot muscle strength is an important evaluating measurement for muscle function of physical fitness in adolescence.

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The aim of this study was to determine the influence of pull-up action on the pedaling mechanics and muscle coordination during short term cycling. Eight male cyclists performed three bouts of cycling for 30 sec on different pedaling images; preferred, emphasizing pull-up action and push-down. Each exercise bout is consisted of the onset of cycling for 10 sec, a constant load cycling for 10 sec and a maximal effort for 10 sec. Pedal force, crank force, crank revolution and EMG signals from leg muscle were measured. A significant difference was observed in the index of force effectiveness (IFE) at constant load exercise phase between pull up images and other two conditions. However, clear differences were not seen in the EMG.

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The purpose of this study is to investigate the muscle characteristics of the support leg based on muscle relative load and dynamics conversion ratio during the support phase in the constant pace running. Eleven male subjects, who are heel strikers, ran at the speed of 3.3m/sec. The musculoskeletal model of the individual subject was constructed by using the SIMM software, and the muscle forces of the support leg were estimated from the muscle force optimization approach that satisfies the net joint torques obtained from the inverse dynamics calculation. The muscle relative load is defined as the ratio of the actual muscle force to the muscle capacity which is the maximum value of muscle force obtained by using the Hill-type model governed by the force-length-velocity intrinsic muscle relationships. Muscle force contribution to the generation of the inertia force of the whole-body was calculated from multi-body dynamics analysis utilizing the equation of whole-body motion, and dynamics conversion ratios of individual muscle were defined as the muscle contribution per muscle force to the generation of the inertia force. The results obtained in this study indicate that (1) dorsal flexor showed small muscle relative load and large conversion ratio, while gluteal muscle showed large muscle relative load but small conversion ratio, (2) each muscle of quadriceps had similar characteristics in the generation of muscle force with the exception that vastus muscle group showed larger conversion ratio than that of rectus femoris during the eccentric contraction phase, and (3) soleus and gastrocnemius generating vertical and horizontal body motion effectively showed almost same relative load values.

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This study was to develop the measuring instrument of muscle strength on hip joint concerned with the movement of walking. The results were as follows. 1) The measuring instrument of incline type developed in this study was better and safer than that of siting type developed in previous study. 2) Each mean value of the age-related change of muscle strength on hip joint was 15.2(±4.7)kg in 50's, 12.9(±3.3)kg in 60's, 11.4(±4.2)kg in 70's, 10.6(±2.0)kg in 80's. 3) There was no significant difference between the experience group and the inexperience group about fall. 4) The exercise for three months in the health class was improved the muscle strength on hip joint for all generations.

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In order to develop lighter power transmission device, bicycle sprocket was made of CFRP using silicone rubber mold. The filling of the carbon fiber cut into 15mm to the silicone rubber type was excellent In the normal mold method was difficult to control tooth thickness by deformation of mold, but tooth thickness control was possible that using split mold of tooth part. The sprocket made of CFRP of VF25% was made for trial purposes by using the silicone rubber mold There was no problem on teeth though it actually run up to 5000km by installing the sprocket made of CFRP in the bicycle.

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In this study, the characteristics of the men's javelin were investigated in terms of its material in order to collect basic data about the required properties of the javelin. Made of various materials (composite materials: 7; steel: 5; duralumin: 8), 20 types of javelins were examined to assess the static characteristics of shape, center of gravity, and moment of inertia, as well as the characteristics of vibration and static bending stiffness. The properties of the composite javelins were clarified, and the effects of javelin material in a javelin throw competition are discussed. Although all the javelins had the same shape, for the composite javelins, wide scatter was observed in the values of the primary resonant frequency, the moment of inertia around the center of gravity, and the compliance at the position of the loop. Therefore, the composite javelins have a pattern of various mass distributions. Further, the composite javelins were stiffer than the steel and duralumin javelins, and exhibited the characteristic that their vibration was easy to damp.

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To analyze the mechanical properties of porous polymers for sports equipment under large deformation, mechanical loading tests and numerical analysis using homogenization theory were described in this paper. Porous polymers are applied to sports equipment such as shoe sole, shin-guard and helmet. In the mechanical loading tests, the fundamental properties of porous polymers for sports equipment and the effect of microscopic pore ratio on the macroscopic mechanical characteristics were investigated. In the numerical analysis, to evaluate the applicability of the simulation program to porous polymers, homogenization analysis of microscopic skeletal wall of which was assumed as nearly incompressible hyperelasticity is demonstrated. The microstructures of porous polymer were assumed to deform uniformly, and the microscopic periodicity remains under large deformation. By comparing the numerical simulation with the mechanical loading test results, the applicability of the proposed model for the porous polymer was shown.

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In a volleyball game, the tension of a net can have a great influence on the outcome of the game. For example, when the ball touches the net, it will affect its direction which can result in an additional score and the power of the rebound can also affect the players. However, there is no specific regulation on the tension of the net. We find it necessary to set a guideline of the net tension in order to provide safety as well as the durability of the equipment. Here in this report, we took measurements of the net rope tension to inspect the force given to the net and the standing poles. The report gives data of relevant measurements of the tension considering the strength of the poles within safety bounds and it also introduces machinery which can measure the net tension.

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The purpose of this study is to develop the simulated vibration source simulator in ski driving based on the new concept which is able to reproduce more than 200Hz machine dynamics vibration affecting velocity in skiing in order to clarify the ski driving mechanism. The simulator used snow mass simulating skier, and it glided over the bottom surface of ski. In experiment, compressor and ball vibrator used as a way of source of vibration, these were able to reproduce the similar vibration in skiing. The experiment was carried out using this simulator. From is experiment, the snow mass velocity was increasing in accordance with increasing of the vibration frequency, and the coefficient of dynamic friction were between 0.018 and 0.035 in snow mass gliding.

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Human abilities decay slowly due to the decline of physical function with aging, and gait disorders can be generated, which narrows people's activities and increases mental and physical decline. Under these circumstances, the recoveries of walking capability have been widely studied. We have already developed Novel Intelligent Lift-Type Walking-Assist Mobile Robot (NILTWAMOR). There are a tracking control system for walking assist and a body weight supporting system for standing posture in NILTWAMOR. On this paper, an omni-directional moving method of lift-type walking assist system is newly developed. This paper mainly proposes a method to identify the current body center of the user for estimating user's intention of walking direction. The tracking control system for walking assist is applied to not only healthy people but also patients of gait rehabilitation in order to demonstrate the effectiveness of the proposed method.

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Badminton is one of the famous sports and enjoyed by people of all ages and both sexes. Recently some sports maker try to produce high quality product because of player and progress of player's level. Firstly, practical badminton machine is developed with a target to meet with player's practice and is produced experimentally with the rotation arm system launch structure from human arm imitation in this study. Then, high speed photography is taken to understand the launch behavior of practical badminton machine and to evaluate launch velocity and launch precision of this machine. It follows that launch behavior is changed by spring grow, gripper angle and gripper shape. Finally, launch behavior is simulated and evaluated. The simulation result is in almost agreement with the one from the practical machine on the launch behavior.

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Variation of motion during baseball pitches with constant effort to be constant speed and control was examined with inertial sensors and strain gauges. The measuring items were the angular velocities about two axes of thighs and leg, the angular velocities of rotation of torso and hip, and forward tilting of torso, the angular velocities of internal/external rotation of shoulder and pronation/supination of forearm, the angular velocities of swing at upper arm and forearm, and strains of nails of 2nd finger and 3rd finger. The variations of the angular velocities during constant baseball pitches were relatively larger at leg and thighs and were smaller at upper limb and shoulder.

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The purpose of this study was to investigate the effect of combined viscous and elastic load training using a variable mechanical impedance device.【Method】 Sixteen healthy men trained maximal concentric elbow flexion of right arm 3d-wk^<-1> for 8 weeks. Isoviscous training group performed 6 sets of 12 on a developed impedance device. Similarly, Combined training group performed 6 sets of 8-10 maximal concentric actions. Isoviscous, isokinetic and isometric strength were measured three times. The muscle volume of the biceps brachii and brachialis were measured by magnetic resonance (MR) images of upper arm at before and after training. 【Result】 Muscle strength and power significantly increased after 8 weeks training, but no significant changes between groups. The muscle volume also significant increased after 8 weeks training, but no significant change between groups.

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In this paper, structure design and modeling of novel seating-type two wheel vehicle with lower position of gravity center is proposed. The vehicle's gravity center is assigned at the lower position than that of the wheel axis, whose vehicle has the structure of the pendulum. Therefore, it enables the passenger to always keep the stable posture, even if the vehicle is in the power-off or control-off state. Then, the gravity center position's adjustment system is installed inside the vehicle body. Swing of the vehicle body generated by the bias of the passenger's gravity center position is controlled by the proposed seat positioning system. As a result, alignment of pitch angle of the vehicle body is possible by a seat positioning system that has been proposed.

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The aim of this study is to realize the experiment of biped running, and we focus on the bouncing rod dynamics and its mechanism. The key point of bouncing rod dynamics is to transfer horizontal velocity into lifting momentum. In this study, we aim at a stable continuous running by the improvement of biped. And, we conducted experiment on running biped with knees.

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The motion of a curling stone is controlled by the frictional interaction between its running band and pebbles on the ice sheet. This paper calculates the net friction forces and torques by use of the evaporation-abrasion model, and shows that the ice friction coefficient on the rear running band is by a factor of A larger than that of the front. The curl ratio was introduced to describe definitely the curl distance as a function of translational and angular velocities of a stone.

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The curl mechanism of a curling stone is not fully understood. We obtained sequential images of the stone movement on a curling ice sheet with two CCD cameras and estimated the curl ratio and ice friction coefficient using the image processing technology. This paper reports details of the measurement methods and results of some analyses.

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