A bunt is a special type of offensive technique in baseball. The sacrifice bunt is most often used in close, low-scored games. The primary goal in bunt is to ground the ball into fair territory. The batter is required to make contact with the ball at a particular place and time by moving bat and hit the ball toward the appropriate area. Different from hitting, the batter had to control the velocity of hit ball. The purpose of this research was to investigate the temporal and spatial bat positions during the operation of baseball bunt. The subjects were seven university baseball players. As the conditions of the direction of the hit ball, we difined three conditoins, bunt toward first- base, pitcher, and third-base. Each trial was judged whether the trial was success or failure on the basis of hit ball direction, velocity, and the angle of hit ball in the vertical plane and only successful trials were analyzed. The height of the pitched ball was classified into three conditions, high, middle, and low conditions. The three-dimensional positions of the head and grip of the wooden bat were recorded using the VICON512 system (120Hz). At the time of impact, not only bat head but also grip position differed due to the direction of the hit ball. When subjects hit the ball toward the third-base, the position of the bat head preceded the grip. The difference of the horizontal bat position was observed from the beginning of the operation among the theree conditions. The subjects also moved the position of both the bat head and the grip in order to adapt to the height of the pitched ball, using lower limb movement.

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The purpose of this study was to characterize the bat swing parameters that increase the flight distance. Thirteen members of a collegiate baseball team performed free-batting practice. The batting performances were recorded with a ultra-high-speed camera and a tri-axial gyro-sensor attached to the grip end of a wooden baseball bat. Flight distance had a high correlation with the kinetic energy possessed by the batted ball (p<0.01) which, in turn, was correlated with the rolling velocity of the bat (p<0.05), the direction of the bat swing (p<0.01) immediately before the impact (p<0.05) and the orientation of the line of impact (p<0.05).

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The purpose of this study was to quantify the contribution of the upper limb joint torques and shoulder joint reaction force to the bat head speed and to the vertical component of the bat head velocity during baseball batting motion. The upper limb segments and bat were modeled as a system of seven-rigid linked segments, and constraint axes of the elbow and wrist joints were modeled with constraint equation in order to consider the degree of freedom (DOF) of the joint Each hand was considered to be connected with the bat through zero DOF joint The equation of motion with respect to the upper limbs and bat was obtained from 1) the equation of motion for each segment, 2) equations for constraint condition in which adjacent segments are connected by joint, and 3) equations for constraint axes of joints. The dynamic contributions of the joint moments, shoulder joint force, motion dependent term and gravity term to the bat head speed and vertical component of the bat velocity were derived from the dynamic equation of the system. A recurrent equation with respect to the generalized velocity vector of the system is derived to calculate the contribution of the joint torque terms, external joint force term, and gravity term to the motion dependent term. Collegiate male baseball players' motion were captured by VICON 612 system (9 cameras, 250Hz) and kinetic data of each hand were collected with an instrumented bat with strain gauges (1000Hz). From the results, the joint torque of knob side shoulder shows large contribution to generate head speed, and the torque generates large downward velocity in the vertical direction.

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There are mainly two kinds of diseases in intermittent claudication. One is lumbar spinal canal stenosis (LCS) and the other is arteriosclerosis obliterans (ASO). Whether diagnosing LCS or ASO is critical issue. Wrong diagnosis might cause patient death. Concerning above, this paper presents a novel approach for classification of intermittent claudication from walking motion. The subject with LED makers walks on the treadmill until she or he feels pain. We measure the walking motion by camera and track the LED markers. Treadmill enables to measure walking motion for a long time, and LED maker provides precious position of every joint in the walking. Then, we can get the information such as joint angle trajectory, hemi-foot step, stance and swing phases without any other sensors like foot switch or force plate. We compare walking motions of healthy parson, LCS patients and ASO patients, find their feature and derive criteria for classification of intermittent claudication. From the results, we reveal that average of ankle joint angles and hemi-foot step would be useful for the classification/diagnosis.

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We proposed a statics-based model to predict knee adduction/abduction moment, which is a major mechanism of anterior cruciate ligament (ACL) injury. Our model neglects the dynamic terms of equation of motion because, at the time of ACL injury, the moment of ground reaction force (GRF) is much more dominant than the moment caused by shank's inertia and gyroscopic torque. As a result of experiment, the statics model well agreed with the Newton-Euler method, indicating that the knee adduction/abduction moment is mainly determined by the moment of GRF. For the kinematics-based moment prediction, the accuracy of the estimated GRF, which was calculated from the acceleration of body center of mass, was also assessed. A possible application of this study may be the risk determination of ACL injury by analyzing the real injury videos.

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In Japan, accidental injury tops the cause of child death. Therefore effective countermeasures against these accidents are required for accident prevention and mitigation. In this study, we performed a simulation of accident reconstruction in order to comprehend accident situation for suggestion and evaluation of effective countermeasures. A multi-body child human model was constructed and used for this simulation. The biofidelity of this child model was evaluated by a series of impact test simulation which represents impact tests for evaluation of Q3 dummy. Using this validated child model, we reconstruct an accident based on an accident data. As a result, a multi-body child human model was reconstructed based on the weight and height data of injured children from accident data. The mass ratio of each body segment and the geometry of the child model were evaluated..

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Rapid and accurate medical treat is required to decline the number of traffic death and injury people, but making accurate judgments is difficult by emergency life guard due to shortage of information for accident. So the purpose of this research is making "A prediction formula of driver's injury" as a tool for accurate judgments. To make the prediction formula, a reconstruction simulation of traffic accidents was constructed, and its accuracy was validated by comparing the results of JNCAP to those of simulation. And it was cleared by the analyzing JNCAP data that differences of type of vehicle and manufacturing year affect driver's injuries, so the prediction formula is constructed with this issue in mind.

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The objective of this study is to predict the behaviors of the human body in pre-crash conditions based on the experimental study. In order to simulate the actual pre-crash condition of a car that occurs when the pre-crash braking system is activated in an emergency situation, low speed front impact tests on human volunteers were conducted. From the result of this experiment, pre-crash occupant behavior was predicted. The pelvis motion was strongly influenced by the muscle activity, relating to the driver's posture just before the collision.

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We have presented AIR FLIPPER^<[○!R]> (normal) and AIR FLIPPER J^<[○!R]> (J), which use air resistance tor rotator cuff exercise. Here we show a new AIR FLIPPER^<[○!R]> (new) in cooperation with Mizuno Sports Co. Ltd. The purpose of this study was to evaluate the effectiveness of the new FLIPPER in training the inner muscle. Five primary school boys, 5 high school boys and adult men. all without shoulder disorders, joined the study. Activities of infraspinatus, posteror deltoid, pectralis major and biceps muscles were examined at internal and external rotation at 1st position, using electromyogram. The results show that the inner muscle was more active than the outer muscles with the three FLIPPER models and that the outer muscles were less active with the new model than with the normal model. It may be concluded mat the new AIR FLIPPER^<[○!R]> is more efficient all for generation.

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The purposes of this study were to suggest and validate a new hopping viscoelastic model which can consider the differences of the characteristics of lower extremities and the time lag of the landing between both extremities. Six healthy male subjects performed fixed rhythm hoppings to measure impact forces. A new viscoelastic model which has two contact points was established. The equation of motion was derived from this model. The parameters of the model were determined by optimization using an objective function which includes a measured vertical ground reaction force. The same procedure was done using an old viscoelastic model which has only one contact point to compare the simulated results. The results showed that the new model could consider the difference between both feet and simulate both vertical ground reaction force during hopping.

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The influence of gait velocity on ground reaction force (GRF) distributions in the contact area is experimentally clarified. To measure the GRF distributions, a shoe mounted miniature triaxial force sensors is developed, the weight is 270.0g. By using the shoe, distributions of lateral, longitudinal and vertical force components at 19 local positions are measured at gait velocities of 4.0, 8.0 and 12.0 min/km. The experimental results show that the GRF distributions have different tendencies in contact area. In comparison of the GRF distributions in 3 gait velocities, it is confirmed that area loaded high force value is clearly different at the time forward GRF reaches minimum, zero and maximum. These differences imply that shoe sole can be independently designed by changing the gait velocity.

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The purpose of this study was to verify the validity of the inverted pendulum model in one step and to propose new models which could accommodate to the several walking speeds. Twelve subjects walked about 10m path at three kinds of walking speeds. Lower trunk acceleration and 3D marker data were recorded. True value of the step length was recorded from 3D marker data and predicted value was calculated by inverted pendulum model whose variable was displacement of the COM. Displacement of the COM was calculated by double integration of the lower trunk acceleration. We proposed the new model which changed the correction factor (K_m) in each step with using regression equation. We evaluated the validity of the model by RMS. From the result of this study, the validity of the new model was higher than previous models at all speeds in each step. So it was suggested that new method was better estimator of the step length than previous models.

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When coming off the blocks at the start of a sprint running race, the athlete accelerates from a static state to maximum sprinting speed. Therefore, knowing how to increase power off the starting block is important. In the present study, the forces applied to starting blocks by sprinters were measured. From starting blocks, six sprinters did the "starting dash" as is done in a sprint running race, and the forces applied to the right and left starting block as well as to the ground during the first step were measured with force plates. As a result, no large difference was observed between the sprinters in terms of the force applied to the back block. However, the force applied to the front block differed between the sprinters, suggesting that the force applied by the front foot possibly affects performance during the "starting dash". Moreover, the force applied to the ground during the first step indicated that there is a possible relation between the forces of the first step and the force applied to the starting block by the front foot. In addition, it was observed that the sprinters applied a force in the right or left direction when the foot struck the ground. Considering these results, further investigation of the effects of step width is necessary.

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It is said that a boxing blow which results in a head rotation is effective. However, the mechanism of a bra in concuss i on by a box i ng b Iow has not been c I ar i f i ed. In th i s study the dynamic behavi ors of an impacted human head by a box ing blow were simulated using a precise human head numerical model. It was shown that a blow to the jaw generates a large head rotation and the high Mises stress in the vicinity of the brain surface and brainstem which plays a role to keep consciousness.

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The objective of this study is to discuss a mechanism of the skull fracture of head injuries due to impact with finite element (FE) analysis and to develop the stress-based head injury incidence boundary. We previously reported the necessity of high shape fidelity head FE models to detect the possibility of fracture on the skull. In simulations using the FE head model (Titech model) which previously was constructed and has been validated, the head model impacted to a rigid plate model with springs where the head injuries could occur. The compression stress on the skull was distributed concentrically around the impact area. The maximum of the compression principal stresses on the outer table in every simulation, which were the largest among these bones, were plotted against the duration time of the stress. We developed the curve connecting a set of the average points in each simulation as the head injury incidence boundary. A simulation considering the fracture of the skull was thought to validate this curve.

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The purpose of this study is to develop the method to distinguish child abuse from accident injury by using anthropomorphic test dummy. In this study, shaking assumed child abuse and falling events assumed unintentional injury were examined. As the experimental conditions, two posture of shaking and gender difference in shaking were defined to clarify these effects on head injury risk outcomes. And also, four fall heights and three surfaces for falling were examined. Subdural hematoma (SDH) and skull fracture were evaluated by the peak change of angular velocity and HIC, respectively. As the result of experiments, shaking events cause SDH due to higher peak change of angular velocity, which exceeds the tolerance value, than the case in fallings. Moreover, both the shaking posture and gender affects greatly on the peak change of angular velocity. On the other hand, falling events cause skull fracture because of the higher HIC value than shaking cases.

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The purpose of this study is to visualize a hazardous location in living environment regarding head injury by falling. In particular, the generalized method applying for various living environments was developed. In the method, general head injury database in case of falling in living environment was constructed. The database is based on large amount of simulation results using a multi-body model for Syears old child. And, the database classified the severity level of head injury in relation to falling height and the distance to the collision surface. In order to visualize the hazardous location in a targeted living environment, the severity level of head injury were mapped on the 3D CAD model of the environment based on the database by calculating the distance and height from standing position to collision objects such as furniture. The method made it possible to easily visualize a living environment in shorter time.

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The purpose of this study is to clarify head injury mechanism such as diffused axonal injury (DAI) under rotational impact by experimenting with a head physical model having actual human shape. A head physical model constructed from individual medical images of a head was used for the experiments. The model consists of skull, CSF, falx and brain, which represents actual human head shape. The model was exposed to angular acceleration by impactor collision causing 4500 rad/s^2 peak rotational acceleration with 5ms pulse duration. After rotating 60°, the model was decelerated with 1000 rad/s^2 peak, 40ms duration. Deformation of the model was measured with full-field by using digital image correlation (DIC). Moreover, magnitude of deformation was determined by calculating maximum shear strain. As the results of experiments, shear strain concentration at the corpus callosum and shear strain communication to depth of brain were observed. The region observed this phenomenon corresponded to the region where DAI occurs most frequently in real accidents. Therefore, shear strain concentration at the corpus callosum and shear strain communication to depth of brain showed important phenomenon in head injury incidence under rotational impact.

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The purpose of this study was to reveal the relationship between stooped angles of upper body segments and lower joint moments during sit-to-stand movement. We evaluated joint moments by using the support moment which was advocated by Winter. There was the relationship between the stooped angle of trunk and lower joint moments. When support moment became maximal value, the percentage of hip joint moment in support moment was high corresponding to trunk angles. At the same time, the percentage of the knee joint moment in support moment was low. There was, however, no correlation between the pelvis angle and lower joint moments. It was, therefore, suggested that lower joint moment made up for each other by adjusting trunk angle.

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In this research, we investigated the interference between left hands and right hands when a mechanical disturbance imposed to one side hand. For this purpose we developed an experimental device which can produce mechanical disturbance by linear actuators. In pinching tasks of the experiment, target pinching force of left hands was that of 10% Maximal Voluntary Gontraction (MVC), and target force of right hands was designed using sinusoidal functions whose amplitudes are these of the force in the case of 0-20% or 5-15% MVC. During these tasks, we measured pinching force of the right hand. The mechanical disturbance is imposed to only the left hand. As a result of this experiment, we figured out that the influence of the mechanical disturbance show different trend depending on the amplitude of the target force of the right hand. In conclusion, we suggested that the mechanical disturbance to left hand facilitate the excitation or inhibition of motor unit of right hand which depend on the timing of the disturbance. This trend could be observed in difficult tasks.

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Electromyogram signals represent motor command from brain and muscle tension very well, and have some advantages as for human interface device. If there is a system which can exercise while seeing an optimized shape of Electromyogram, it can tie to early mastery of motion. So in this research, simulation analysis to optimize the Electromyogram was done to the arm model by using Genetic Algorithm. The model was two link arm model consisting of a forearm and a hand, and had the characteristic of a extensor and a flexor. The electromyogram obtained from the throwing experiment was compared with the myogenic potential optimized by the simulation about throw of the ball.

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This paper considers the problem for constructing and reconstructing characters and words from handwriting experiments. First, handwriting motions are measured using a pen-tablet and stored as a 3-dimensional time series data. Then, the data is used to construct characters and words by employing the 'dynamic font' model and the theory of smoothing splines based on the minimum hand jerk model. Moreover, we propose a tuning method of the so-called smoothing parameter from an esthetic viewpoint of the resulting cursive characters. The effectiveness of the method is verified by experimental study.

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The human tactile sense can feel sensitively the sharp stimuli although resolving power is low in many parts of human body. In this study, we note a parameter of this sharpness and propose the tactile sensor which resembled the human sense of touch characteristic that can acquire this parameter. The proposed sensor can classify the contact which is crowded or scattered using the decay time of its output. The present study is to realize the function of the receptive field in the living body by using a simple analog circuit, and is a fundamental study to apply them to the tactile sensor.

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Estimation of joint torque is one of motion analyses of humans; it has been applied to virtual reality, sports training, welfare engineering and so on. Especially the estimation of leg's joint torque is very important because the legs are one of the most active and energetic regions for a human life. This paper presents a design method of the leg's joint torque estimation system that adopts a partially constrained parallel wire driven structure. From the viewpoint of parameter scattering of target legs, we demonstrate the decision method of the wire-arrangement and actuators.

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The Anaerobic Threshold (AT) is defined to an exercise of the maximum workload when it can be performed without the continuous blood lactate concentration rising while the gradual increasing exercise. AT is widely used as an index of the safe and effective exercise workload in exercise therapy. To determine the AT, the blood lactate measurement with blood sampling or the ventilation measurement is needed. The blood sampling can not be performed except the medical licensed doctor or nurse, the ventilation measurement is needed a very expensive device. The purpose of this study is to make the procedure to estimate the AT using the vital signals such as the electrocardiogram (ECG), the Electromyogram (EMG) and breathing curved line (BCL). From the preliminary experiment (Experiment 1) result, the BCL was focused as the index for AT estimation in this study. AT estimation using the BCL summarized as follows ; 1) AT could be estimated by the following tendency in the gradual increasing exercise; the peak power in spectrum of the BCL transferred from the low frequency component range to the high frequency range over the AT level under the exercise 2) AT could be estimated by the following tendency in the controlled respiratory frequency of 27-28 [breaths per min] ; the power in the frequency equaling to 27-28 [breaths per min] increased immediately after the over AT level in the gradual increasing exercise.

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The purpose of this study was to propose a simple method for forward dynamics analysis of human movement which is able to consider the constraint axes of joints without needs of tirne-consurning procedure for the derivation of dynamics equation of the system. The dynamic analysis method, which is based on the equation of motion of the system, has an ability to quantify the contribution of the joint torques, external force, motion-dependent term and gravity term to the generation of kinematic and kinetic variables, such as, speeds of target points, angular velocity of the segments, body eg velocity and angular momentum. The equation of motion with respect to the target system was obtained from 1) the equation of motion for each segment, 2) equations for constraint condition in which adjacent segments are connected by joint, and 3) equations for constraint axes of joints. The validity of the proposed method was clarified with a simulation about a swing motion of the upper extremity.

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The purpose of this study was to propose a converting algorithm of the motion dependent term into joint torque terms, external joint force term, and gravity terra The motion dependent term make significant role for generating end-point speed of linked segment system, especially, in high-speed swing motion, such as, volleyball spike, baseball pitching and batting motions. The motion dependent term is mainly caused by linear and angular velocities of the segments, and these velocities are the results of joint torque and external joint force inputs into the system We convert the motion dependent term into other terms by using the equation of motion expressed in the discrete time system. A recurrent equation with respect to the generalized velocity vector of the system is derived to calculate the contribution of the joint torque terms, external joint force term, and gravity term to the motion dependent term. From the results obtained in this study shows that shoulder joint force play a significant large role in generation of racket head speed for skilled player in tennis serve motion.

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Recent years have seen a worldwide increase in people participating in Nordic Walking with a heavy concentration in Northern Europe. This trend has led to abundant research in Nordic Walking. In these preliminary studies, however, whether the conclusions that this type of exercise is effective in reducing load on the lower limbs has been contradictory. To clarify the effects of reducing load on lower limb joint on Nordic Walking, this study measured the load on lower limbs joints during Nordic Waling on a level surface with three test conditions (free walking, speed constraint, speed and stride length constraint). Results revealed no significant differences between Nordic Walking and Ordinary Walking with speed constraint, speed and stride length constraint. Additionally, the effects of joint load resulting from difference of stride length were clarified.

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The objective of this study is to collect precise material and structural properties of older population and build a anatomically detailed finite element thorax model to predict crash induced chest injuries. Whole twelve ribs in right side of ribcages from seven fresh cadavers were prepared for microCT scan and three-point bending test. The thickness distribution of cortical bone was measured from microCT images. Nine cross sections in the axial direction and sixteen points along the circumferences in each cross section were sampled to measure the cortical bone thicknesses distribution. Each rib was dissected equally into the three pieces (anterior, lateral, and posterior) for three-point bending test. Bending stiffness and fracture moment were measured and statistically analyzed with regions (i.e., anterior, lateral, and posterior in axial direction) and rib levels. A finite element thorax model was built by taking these detailed material and geometric information into consideration. The rib fracture behavior was simulated by modeling both cortical and trabecular bones using elasto-plastic with damage material type (EWK in Pam-Crash). Model response to impact (Kroell's frontal pendulum) and dynamic (Kent's hub, distributed, single and double diagonal) loadings is provided in this paper.

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Deflection of the ski, ski-snow contacting pressure, boot-ski loads have been measured during the turn on the snow slope on the two skis of different bending stiffness distribution. The result shows that the ski-snow contacting pressure distribution is different in spite of that boot-ski loads and ski deflections are similar in the same carving turn remaining the same snow groove. From the deflection data, snow groove dimensions and measured pressure distribution, ski-snow contacting situation have been estimated by the correspondence between the deflected edge line with edged ski sliding surface and the snow groove surface. The idea that the front part of the ski bends to compress the snow surface and rear part of the ski rides on the formed snow groove surface is validated from the investigation. The difference of the ski-snow contacting pressure distribution attributes to the difference in the bending stiffness distribution of the ski.

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This study is aimed at building a new design concept of a ski boot that can improve the results of Japanese alpine ski races. In this paper, new design of an upper shell of a ski boot that was adjusted to the features of the frame of Japanese alpine ski racers was analytically and experimentally examined. As a result, it was demonstrated that a front and a rear part of the upper shell of a ski boot should be separately adjusted to the length of a shank of each player for well-balanced quick lean of the leg in the ski turn. Finally, the effect of new design of an upper shell was verified in laboratory experiments on leaning balance and field tests for RSV by Japanese female ski racer of the first rank.

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The purpose of this study is to get a basic knowledge about the aerodynamics about the race suit and the sled surface form processing in the luge sport. The luge sport is adopted as one of the sled sports in the Winter Olympics game, and it is one of a certain very popular sports in Europe. A player rides on the sled, and drives on the luge track at a speed which reaches best 140km/h on the ice track. It becomes the important point of view of the performance boost how aerodynamic drag is reduced in sliding. The influence of the driving form that it is formed by a sled with the player was verified at 2m x 2m Low-speed Wind Tunnel of Wind Tunnel Technology Center in JAXA. We inspected a measurement in JAXA (Japan Aerospace Exploration Agency) whether profiling of the treatment of the race suit and the sled surface had influence that how was it on aerodynamic drag this time. That we could plan reduction of the aerodynamic drag was inspected by doing the race suit surface in the shape of several kinds of stripe. In addition, we was going to inspect it how aerodynamic drag changed by affixing tape to the surface of the pod of sled in the shape of stripe.

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Initial 40-m part of a flight of 120-m jumping after take-off was recorded by a fixed high-speed video camera at a frame rate of 250 frames/sec at Hakuba Ski Jumping Stadium in Japan. Aerodynamic forces were derived from the image data analysis of high-speed video image of ski jumping flight. The time variations of the forward leaning angle and the ski angle of attack were also taken from the video image. Based on these time variation data, we defined the time of the transition to the quasi-steady flight, which may be equivalent to the time for the completion of the initial take-off motion. Some correlations were investigated between the jumping distance and those key angles and the initial transition time. It is found these key data are appropriate measures for the jumping skill.

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The purpose of this study is to develop a new convenient test method that is helpful for runners to select appropriate shoes more easily. Recently motion analysis on treadmill running has been available in sports shoe shops. Through the results, runners can recognize shoes stability required. However this method cannot give runners information concerning cushioning. In this study, we investigate the relationship between the loading rate of ground reaction force during ground running and the acceleration peak value obtained on a treadmill running. Therefore it was found that there was moderate correlation between them. This indicates that the acceleration peak on treadmill running can be available for investigation of cushioning property required for runners.

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The purpose of this research is to estimate the angular velocity and direction of the rotational axis of the flying disc by a tri-axial accelerometer. A subject performed throwing by using the flying disc attached the accelerometer. The closed up release and catching point images were acquired using the high speed cameras. The angular velocity was estimated from the centrifugal and angular acceleration. Estimated angular velocity was compared to the calculated angular velocity by the high speed cameras. The angular velocity estimated by both the accelerometer and the high speed cameras were quite similar.

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This paper proposes the new motion measurement method in sports using the motion measurement system installed inertial and magnetic field sensors. This system provides tri-axis angular velocity, tri-axis acceleration and tri-axis magnetic field. Introducing the sensor fusion algorithm using adaptive Kalman filter, the effect of magnetic disturbance is compensated. Furthermore, the advanced sensor fusion algorithm is constructed using quaternion to enable motion measurement in wide range of motion. In order to confirm the accuracy of proposed measurement methods, we compared the value obtained by the proposed methods with the value of encoder. It is found that these methods provide the accurate value in the motion analysis in the space with magnetic disturbance and in wide range of motion. Consequently, the proposed methods in this paper can be used to the motion analysis in various sports.

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In the designing process of sporting gears, designers should consider the practical conditions. In case of ground golf club, the practical conditions mean grip force. Because vibration properties such as eigen-frequencies and logarithmic decrements obtained from under free condition are quite different from the practical condition. In this study, the above vibration properties under the practical condition are measured by using sensor glove system and modal analysis. The dependences of grip force upon the vibration properties are introduced. Moreover the validity of the FEM considering the grip force is discussed. As a result, it has been found that eigen-frequencies and logarithmic decrements under free condition and a practical condition were predicable by using the FEM in this study.

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In recent years, the measurement of plantar pressure and reaction force has been utilized not only for an improvement in sports performance but also for the walking rehabilitation. Therefore, the device system for measuring reaction force at any specified place has been developed to a truly practical level. This paper presents a novel insole system by using the traditional Japanese socks with two-sheet structure, referred to as 'tabi', in order to measure the reaction force on daily movement behavior. In addition, its effectiveness is confirmed by several experimental results derived from the force plate. It is expected that the proposed techniques will highly enlarge the motion analysis target on daily movement behavior.

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A new water-mat including water in the baggy mat was developed for bedridden persons and persons in need of nursing care. The positions, sizes, number and shape of some weirs and some orifices in the water mat control a flow of water in this mat. This mat is designed to have a good body pressure distribution and to follow smoothly the posture of patient, For the water-mat designed and manufactured, some experiments were made as the capacity of compression pressure, the freezing characteristics and the body pressure distribution. The mattress including this new mat is manufactured for the persons who are unable to change their posture by themselves and, then sold by a bed maker

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The purpose of our study was to develop an activity monitor system for the energy expenditure in water walking in the swimming pool. In order to establish an estimation equation for the energy expenditure in water walking, the authors conducted a physiological experiment for adult subjects. The authors hypothesized that the oxygen consumption in the water walking consists of the basal metabolic energy, the joint consumption energy and the propelling energy. Therefore, the individual physical parameters and his kinematical data, such as walking velocity, body acceleration were adopted for the variables for the estimation equation. Adjusted coefficients of determination of the estimation equations on both the male and the female were r^2 = 0.735, r^2 = 0.730 respectively. Based on our developed estimation equations, the authors prototyped a wearable activity monitor with 2.4GHz wireless function for the walkers. This wearable activity monitor designed to be attached on the ocipital head of the walker and measured both the acceleration and the position. Measured data were sent to the database server and calculated the energy expenditure in real time. Then, total walking distance, expenditure energy were transmitted and delivered to the walker by the bone conductive speaker.

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SMART-system is a video database developed in JISS. It has been opened for all National Sports Federations from the year 2007. Since then, more than 12 National Sports Federations are using, 752 users are registered, and 42196 video files are archived at the date of Sept. 2009. The experience of providing this software teaches various things : (1) Archiving is categorized to competitions videos and daily training videos, (2) Each National Sports Federations uses this software with different purpose according to their strategies, (3) Positive watching is important to use this kind of software to improve sports performance, (4) Meta-data gathering and it's uploading are one of the tedious tasks of the system, and it should be simplified.

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The purpose of this study was to examine influences of the arm swing velocity on kinetic variables of lower extremity on squat jump. Eighteen healthy male subjects were recruited to perform the squat jump with arm swing (SJA) and without arm swing (SJ). Landmark positions and ground reaction force were recorded by 10 high-speed cameras and 2 force-platforms, simultaneously. Kinematic data (angle and angular velocity) and kinetic data (torque, power, and work) were calculated. The results showed that the performance of SJA (34.6 ± 5.5 cm) is significantly higher than that of SJ (29.8 ± 4.5cm). There were no relationships between the arm swing velocity (at takeoffand peak value) and the jump height. The hip joint angular velocity was affected by the arm swing. There was a trend of a positive correlation between the shoulder angular velocity and the ankle angular velocity at the takeoff. As a result, these results suggested that the arm swing motion increased the ankle power significantly and the larger ankle angular velocity helped the hip power and the ankle power act effectively on jump.

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Pole vaulting has progressed rapidly in terms of improved mechanical properties and better appearance by using poles made of flexible fiberglass material. Competitive pole vaulting requires specific characteristics that promote higher jumps. In this research, simulation analysis to optimize the joint torque, pole stiffness and pole length was done by using Genetic Algorithm. Here, the vaulter was expressed by the three-dimensional model including twisting the waist. Genetic algorithm in which the joint torques of the vaulter were expressed in terms of spline interpolating curves. From the results, it was clarified that there is optimal pole characteristic to the vaulter's initial velocity.

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The purpose of this study is to investigate the relationship between the parameters of human running model and a cushioning efficiency in a vertical ground reaction force in human running with three different sports surfaces. Seven experimental running data were used for searching an each set of parameters for mathematical model of human running without sports surface. The mathematical running model with each parameter set was dropped on the mathematical sports surface model proposed by Kobayashi and Yukawa. In order to investigate the influence of parameters to the ground reaction force absorption, a sensitive test was adopted with ±3% range of parameter value with an analysis of runner-sports surface coupled system. In this paper, the relationship and the sensitiveness of each parameter and the cushioning characteristics in vertical ground reaction force was discussed.

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The motions of hammer were analyzed to understand the mechanism of acceleration using variable-length pendulum and hula-hoop model using energy pumping mechanism. The condition that makes the time derivative of the energy positive is derived as energy pumping for hammer. The condition is expressed in terms of tugging force times velocity to pump hammer energy and tangential acceleration on the handle. In this study, motions of hammer were analyzed and numerical experiments were performed to examine the validity of the theory.

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Footwear durability mainly depends on the sole fractures. In order to produce various functions such as shock attenuation, stability, flexibility, grip and so on, shoe sole is fabricated by the combination of materials with different properties. Accordingly it is well known that delamination in mid and outer soles is one of the most representative fractures and the onset is related to shear strain components. In this study, a new designing method based on shape optimization technology is introduced. From the deformation of sole cross-section in width direction under the practical condition, numerical model and analytical conditions are decided and shape optimization whose objective function is minimization of Von Mises stress in midsole area is applied. Through the analytical procedures, it was confirmed that not only midsole structure but also interfacial shape made a great influence on sole durability.

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EVA (Ethylene Vinyl Acetate) foam with low fabrication cost and good durability has been usually applied to shoe midsole. In the designing process of shoe sole, the material properties must be clarified. However the foam has high non-linearity and strain rate dependency. It is well known that the properties are strongly effected by raw material content and foaming ratio. In this study various EVA foam sheets with different contents and foaming ratio are practically fabricated. The material properties under not only static compressive loading but also dynamic loading conditions, and both the results are compared. Therefore it was confirmed that energy loss which can be an index of sole cushioning depends on strain range in plateau region under the static compression.

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In the designing process of running shoes, it is important to evaluate their performance of several key functions, including cushioning, stability and fitting. The methods used in these evaluation should be simple in order to cut cost and save time. The purpose of this study is to develop a simple evaluation method for running shoes stability. The new evaluation method is based on the center of pressure displacement in the shoe medial direction (dx) during the support phase of running. Three runners with different gait patterns were analyzed and the relationship between ankle joint angles and dx were considered. All results indicate a significant correlation between maximum heel eversion angle and dx at the appearance time of local minimum value on vertical ground reaction force. Furthermore, for the application of the practical shoes designing, we consider the effect of localized sole dent positions on dx. It is confirmed that a localized dent in the rear medial side is effective for stability improvement.

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The purposes of this study are to investigate the effect of the elastic energy of the crural muscle-tendon complex on sprint performance and evaluate the function of sprint spike shoes. For these purposes, subjects performed a planter flexion jump (PFJ), a counter movement jump (CMJ), and a drop jump (DJ) using a slider seat, while wearing the spike shoes. As these results, the positive correlation was admitted between the use of the elastic energy and the increase of mechanical power in spike shoes of elasticity valuing.

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