Ski jumping is a sport which competes the flight distance and the flight form, and jumpers attempt to fly as far as possible. In the regulations for ski jumping competition, the outstretched fabric must show a medium air permeability of a minimum of 40 liters per m^2/sec with 10 mmAq differential pressure. However, the effect of the air permeability of ski jumping suits on aerodynamic characteristics has not been completely clarified yet. The purpose of this study is to investigate the effect of air permeability of jumpsuit fabrics on aerodynamic characteristics, and three types of fabric with different air permeability are examined from aerodynamic point of view. The wind tunnel experiments were carried out using the fabric clothed elliptic cylinder. The aerodynamic forces and static pressure distribution were measured for three types of fabric with different air permeability. For Gap-2 (high air permeability case), the angle of stall increases in contrast to the other cases. The boundary layer flow is affected by the air permeability of the fabric clothed elliptic cylinder.

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The decrease in fluid resistance is one of the important keys for the purpose of shortening of the sports time record. By wearing of a low resistance swimsuit, it still reminds us that there were a lot of large time record shortening in swimming races of Beijing Olympic. The development of low resistance cloth as the application to sports is very important. The fluid resistance were investigated by the change of cloth materials, surface roughness, surface processing method, seam position and the difference in sewing. This study is intended to suggest the best piece of cloth in specific speed area of sports.

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In this study, the effect of microscopic structure on mechanical characteristics of stretch fabrics were evaluated for reasonable design of sports wear. Stretch fabric shows anisotropic mechanical behavior because of its microstructural effect. In order to obtain the macroscopic mechanical characteristics of the fabric, uniaxial tensile tests were conducted. Also, the deformation of the yarn was recorded by the microscope video measurement system to investigate the effect of microscopic structure on the macroscopic mechanical characteristics. The recorded videos were analyzed with motion image analysis software TEMA (Photron Ltd.). From the analysis result, microscopic strain and the angle between warp and weft yarn were obtained. The microscopic behavior of stretch fabric was clarified comparing microscopic strain with macroscopic stress. Correlation coefficients about fitted curve parameter and yarn parameter are obtained.

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The calculation of joint torque generated by competitive swimwear using the skin strain simulation was investigated in this paper. An anisotropic hyperelastic model considering cyclic deformation of swimwear fabrics was introduced in order to reproduce the mechanical characteristics of swimwear fabrics. The material parameters of the proposed model were approximated by using the cyclic tensile loading test results. In addition, the pressure measurement tests were conducted to measure the pressure of swimwear. The theoretical pressure calculated by the proposed model showed similar trend of pressure measurement tests. Next, the stress calculation of swimwear was investigated using the proposed model and the skin strain simulation. The skin strain simulation is able to get the human skin strain of during various motions. Finally, hip joint torque generated by the swimwear was calculated from the calculation results. Therefore, the calculation of hip joint torque generated by swimwear enables the new design of swimwear considering the value of hip joint torque.

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The purpose of this study is to develop the method for designing sportswear that takes into account the solar irradiation. We calculated the net solar irradiance level by using the solar irradiation vector, the irradiance level and the normal vector of surface of the human CG model, and visualized the contour on the human CG model. On the basis of this data, we made a prototype of the sportswear that highly light-blocking fabric and highly breathable fabric are allocated on the appropriate region. This prototype is suitable under hot environment.

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The objective of this study was to construct a finite element (FE) model for a carbon fiber reinforced plastic (CFRP) club shaft which was capable of representing mechanical properties of a fiber and matrix, a laminated constitution and a fiber orientation angle, and to estimate the dynamic behavior of a golf club with a CFRP shaft during the swing. The FE model of a CFRP shaft with orthotopic elasticity was constructed using four-node shell elements. The fiber orientation angle was set by constructing a local coordinate system in each element of the shaft model. Mechanical properties of a prepreg composites were determined using the rule of mixture which was defined by volume fraction of fiber and resin. The simulation results generally matched the experimental results for the bending and torsional tests, respectively. It was indicated that the results for the swing simulation had the potential to clarify the influence of mechanical properties of clubs on the club behavior during swing and the impact conditions.

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The optimum design of the golf club contains the uncertainty that is attributing to variability of swing motion. So, in the purpose of this paper is designing golf club that can do the highest performance for users at any level. It is enabled by approximating the swing by experimental design and response surface, and FEM. For beginners whose swing is unstable, self organizing map is used to predict the type of swing. Using these calculation method, All types of users are supplied the best club which matches each swing type.

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Rubber-ball baseballs are softer than the balls used as official baseballs in Japan. When rubber balls are hit by a baseball bat, the dynamic property of the rubber ball is complicated, because the impact deformation of a rubber ball is larger than that of an official ball. In this study, it was proposed that a composite bat has a high hitting performance when used with a rubber-ball baseball. The materials of this composite bat include an aluminum alloy in the barrel part, a CFRP (Carbon Fiber Reinforced Plastics) in the grip part, and it was coupled with a polycarbonate in between both parts. The hitting performances of the proposed bat and a metal bat (aluminum alloy in all parts) were simulated using finite element analysis. Through hitting simulations, ball types were examined with no-spin (knuckle ball) and back-spin (fastball) pitches, and vertical offset distances (height of the center distance between the bat and ball) were changed from 0 to 20 mm. From the results of the simulation, the composite bat was bending more than the metal one at the point of collision with the pitched ball. In the case of the back-spin ball pitch being hit by the composite and metal bats, the vertical angle of the ball after being hit was decreased approximately 3.0 degrees in comparison with the no-spin ball.

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Wood, metal, and various composite materials are used in manufacturing baseball bats. Metal bats are advantageous over traditional wooden bats in terms of improved strength, lower cost, durability, etc. Knowing the restitution performance of a metal bat according to the ball's wide range of impact velocity is important. In this study, a numerical analysis model of the metal bats was designed, and the effect of impact velocity of the ball on bat-ball coefficient of restitution (BBCOR) was examined from both sides of the experiment and numerical analysis. Impact velocity of the ball was changed from 33 to 67 m/s, and the rebounding velocity of the ball was measured during the experiment and numerical analysis. Furthermore, it was determined whether BBCOR depends on either the restitution performance of the ball or the bat. Subsequently, BBCOR was shown to decrease with increasing impact velocity, and the numerical analysis result showed that the restitution performance of the ball greatly influenced BBCOR.

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According to the Japanese official baseball rule, the use of the wooden bat is required in professional baseball, non-professional teams and university league. Recently, the domestic wood materials for baseball bat dried up and the bat with the import wood from North America is used now in Japan. On the other hand, the bamboo bat used for training conventionally has characteristics such as abundant material and cheap, but is not used in the game because rebound performance, strength and rigidity are small compared with wooden bats. Therefore, in this study, the some bamboo composite bat composed by hickory and maple was made for the experiment, and the rebounding performance investigated by the ball collision test in the high speed using the air cannon system. As a result, the rebounding performance of the bamboo composite bat that is equal to the conventional wooden bat was obtained.

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The tool to support the design of tennis racket is proposed by introducing the fundamental stiffnesses of the tennis racket. The fundamental stiffnesses consist of the in-plane bending stiffness, out-of-plane bending stiffness and torsional stiffness of a part of tennis racket. Since the tennis racket is designed by the bending stiffness distribution of a racket, the relation between the introduced fundamental stiffness and the bending stiffness distribution of a racket must be clarified. Hence these stiffnesses are predicted by the finite element analysis where the shape of racket and the composite structure are considered, and then compared with the measurement. The FEM prediction does not quantitatively agree with the measurement, but the ratio of two stiffnesses is in good agreement with the measurement with respect to two kinds of composite structure of tennis racket.

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We aim to clarify dynamics of the wrist turn of a golf swing and the effect of the parameters on dynamic behavior at the wrist turn with simple approximate equations. We model the dynamic behavior of the wrist turn as a free vibration of double pendulum system. At first, we carry out the eigenvalue analysis for the rotating double pendulum system and calculate transient response of the wrist turn using the modal analysis method. Through the discussion, we derive essential parameters which can give us a physical insight to understand the dynamic behavior of the wrist turn. Next, we convert the equations of motion of the two- degree-of-freedom double pendulum system to a single-degree-of-freedom pendulum system because the dynamic behavior of the single-degree-of-freedom system is easy to understand. Finally, we derive a very simple approximate equation which can express the effect of parameters on the head speed at the impact without numerical integration.

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The purpose of this study is to clarify mechanism of the balance during the golf swing. In the golf swing, inertial and centrifugal force are applied to the player's body. In such case, golf player carry out weight shift to keep balance. At first, we conduct dynamic analysis of the swing using the model of double pendulum likened arm and club and model of human trunk, to calculate the trajectory of the center of pressure. We carry out experiment to measure the trajectory of center of pressure during golf swing by using the force plate. Next, the effect of the weight shift on the trajectory of examined by using a simple mathematical model of the human body. Through the discussion, it can be seen that the acceleration pattern of the human trunk influence on the center of pressure significantly.

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We developed a method to calculate the coordinates of markers on the club head through one set of camera. This method is enabled by setting the club head at some known postures and taking the photos of each posture. So we could measure the three-dimensional postures of the golf club head with markers applied to any positions of the club head with a camera. Following points are made in terms of the measurement accuracy. (1)The measurement error can be decreased by increasing the number of rotation axis which we rotate the club head around. (2)The measurement error can be decreased by increasing the number of the postures we set. (3)The measurement accuracy of the current method is lowered comparing to the three-dimensional measurement machine measuring the coordinates of markers.

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Golfers expect to hit a golf ball correctly by their golf clubs which concern driver. However, not only volume of head of the golf club but also coefficient of the golf club was restricted by the effect rule of the spring of the United States golf society. Therefore, it is hard to differentiate clubs spec of golf clubs. Then, the implementers of golf club increase these lineups of shaft and they provide the club fits for an individual. As for one of techniques, "Database fitting" was established by SRI. In the future, the implementers would like to provide custom-made shaft for each golfer. For achieving this purpose, it is necessary to replicate moving of shaft in swinging by simulation. There is a number of same generic simulation software, but it is hard to change shaft parameter. Improving these issues, we developed software which is capable of changing a shaft parameter more easily. In the past, we made swing simulation software as a first step. However this simulation software needs a lot of simulation time because simulation model have a lot of degrees of freedom. And so we employed mode synthetics method to reduce degrees of freedom which replicate golfers swing. In this report we calculated inertia force in golf Swing as double pendulum model. Using this inertia force, we simulate shaft dynamics in golf swing by FEM model of a club. Moreover we made grip model that replicates a golfer grip and analyzed using this model.

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The purpose of this study was to examine foot grounding by investigating how ground reaction forces and leg motions at grounding vary as velocities increase from walking through sprinting speeds. The participants were 3 male university students. They moved along a 12 m straight course at 6 velocities from walking to sprinting, and stepped on a force platform along the way. Three high-speed cameras synchronized to a video counter recorded their legs and feet as they moved. The velocities of movements and motion parameters were calculated by two-dimensional direct linear transformation method. The results were as follows. (1) The tendency for toe grounding increased with greater velocity. (2) As the tendency for toe grounding increased, the grounding time became shorter and the leg swing velocity increased. (3) At grounding, the knee joint angle decreased with increasing velocity. Regardless of the movement velocity, the ankle joint angle was 90° to 100°.

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The motor tasks of the running motion are to propel and support the body with counteracting the gravity. The functional roles of support leg joints are braking/propulsion and support of body during the support phase in the running motion. The purpose of this study is to clarify the influence of the running velocity on the dynamic functional roles of the support leg joints in the constant pace running motion. Seven runners, who were heel strikers, participated in this research and ran at the speed of 6, 5, 4, 3 min/km. Dynamic contributions of the joint torque of the support leg to the whole-body's CG acceleration are calculated from a dynamic analysis utilizing the equation of the whole-body motion. The results obtained from this study are that (1) the contribution ratio of the eccentric component of the hip extension torque increased due to the increased torque on the hip joint with increasing running velocity, (2) although the change of the contribution ratio of the knee extension torque was small in the body support direction, the change of the ratio of the eccentric component increased and that of the concentric component decreased with increasing running velocity , and (3) the ankle joint contributions to the body support and propulsion were induced by the increased ankle joint torque and additionally the body propulsion was enhanced by the change of the dynamic conversion coefficient, which transforms joint torque to the whole-body's CG acceleration, of the ankle joint caused from the change in the shank segment angle.

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Recent bipedal walking researches suggested that it was useful to treat the COM behavior as an inverted double pendulum because there was a positive correlation between the angle of the upper inverted pendulum and walking speed on level walking and incline walking with free foot strike pattern. However, there is no research which analyzes the relation between the upper inverted pendulum angle and walking behavior with various foot strike patterns. Therefore, in this study, we measured incline walking on slope whose gradient is 15 degrees with three foot strike patterns (Free strike, Toe strike and Heel strike) and analyzed the relation between walking speed and the upper inverted pendulum angle at each foot strike pattern based on the inverted double pendulum. As a result, we found that there was a positive correlation between walking speed and the upper inverted pendulum angle with all foot strike pattern (R = 0.38-0.83). This showed that human utilized their upper body to adjust walking speed regardless of foot strike patterns.

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Pump have been widely worn by ladies in various scenes. The most characteristic of pump is heel plugs with various height, it is very effective to make the ladies' style more beautiful. On the other hand, the specific structures make bad influences on shoe functions such as stability, cushioning, fitting and flexibility. In order to satisfy the above functions, this paper focuses on the sockliner designing. First, with increasing the heel position, foot geometry change is systematically measured by INFOOT systems. Based on the measurement results, sockliners are practically manufactured. Through walking motion analyses with sockliners manufactured, the effects are quantitatively evaluated. Therefore it was confirmed that the sockliner with the correct geometry could relax the foot pressure at MP area.

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Considering the safety in trail walking, stability is an important footwear function. As a parameter of the stability, the amplitude of body's center of mass(Wx) in the lateral direction has been focused. The purpose of this study is to clarify the influences of external factors on stability in trail walking. Through the motion analyses on even surface, it was found that averaged angle of GRF in the frontal plane during single stance, step width and toe direction were significantly related to Wx. Moreover the motion analyses on various uneven surface and with wearing various weights based on actual trail scene were also carried out. It was suggested that characteristics of unstable surface could be a parameter for considering the stability. It was also clarified that the wearing weight on his back made a great influence on Wx.

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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 an assistance of single string. And, we conducted experiment on running biped with knees.

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Fitting is one of the most important functions for footwear designing, regardless of user's skill and category. The purpose of this study is the proposition of a new fitting evaluation method under the wearing condition. By using the sheet with highly sensitive sensors, pressure distribution between the foot and footwear was directly measured under the wearing condition. Then, we proposed PDI (Pressure Dispersion Index), which was calculated from differenciation of the pressure and the human sensitivity distribution. By comparison of PDI and sensual test, the validity of PDI was checked. Furthermore, the influence of foot type, shoe-size and local pressure upon the PDI was quantitatively discussed.

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The purposes of this study were to quantify the function and sequence mechanism of support leg joint torques and to investigate influences of shoe sole bending stiffness on the mechanism in the acceleration phase during sprinting motion. The functional roles of support leg joints at 1st, 3rd, 5th and 7th steps from the crouch start were analyzed by quantifying dynamic contribution of the joint torques to the generation of whole-body CG acceleration using the equation of whole-body motion. Since ankle joint plantar torque, which shows eccentric torque generating type in the first half of stance phases at individual steps, is the largest contributor to the body propulsion and support, the mechanism of generating dorsal angular velocity at ankle joint was investigated by using the equation of whole-body motion to clarify the contributors that induce the eccentric ankle joint torque. Then, the effect of shoe sole bending stiffness on the dynamic contributions of joint torques was investigated. The characteristics of sole bending stiffness about MP joint axis for sprinting spikes and training shoes are approximated by the polynomial function. The results obtained in this study indicate that 1) body propulsion and support are mainly caused by the ankle joint torque in the acceleration phase during sprinting motion, 2) the major contributor to eccentric ankle joint torque, which is observed in the first half of stance phase, is hip joint torque, and 3) the dynamic contribution of support leg joint torques are affected by the step number and the sole bending stiffness.

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In a designing process of functional footwear, it is necessary to well-understand biomechanics of the foot/ankle complex. The purpose of this study is to develop 3-dimensional foot/shank musculoskeletal simulation model which can predict foot deformation and foot-shank interaction behavior under various loading conditions. Foot/shank model include knee joint was developed by using SIMM (Software for Interactive Musculoskeletal Modeling, ver. 7.0, MusculoGraphics Inc.). In the model, lower extremity was defined as 15 segments and 14 joints based on multi-body dynamics. Talocrural joint, Subtalar joint, Transverse-tarsal joint, Tarsometatarsal joints, and Metatarsophalangeal joints were considered anatomical rotation axes, and they were constrained by 15 ligament models represented as non-linear elastic ligament element. As a result, it is confirmed that the developed model provided good agreement with foot joints behaviors in the previous studies, and foot-shank interaction behavior via Subtalar joint (e.g. tibial internal-rotation caused by subtalar-pronation) could be simulated. Furthermore, the model clarified influences of foot ligaments on rigidity of medial longitudinal arch. It is expected that the developed model provide useful insights to design footwear considered foot-shank joint mechanics.

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Study Design: Cross-sectional study. Background: Studying how running-specific prostheses are set, can give amputee sprinters a competitive edge. Objective: Study how sagittal plane alignment changes in running-specific prostheses affect ground reaction forces (GRF). Method: Three transtibial amputees sprinted on a straight track using running-specific prosthetic feet. Sprint movements were recorded using a Vicon-MX system and floor reaction force measuring devices. The experiment level was set with normal alignment for test subjects as regularly recommended alignment (REG), 4° dorsiflexion from REG (DOR), and 4° plantarflexion from REG (PLA). Results: Impulse and average values of GRF showed significant differences in the vertical direction. Difference in foot contact time was insignificant. Conclusion: GRF is affected by sagittal plane alignment changes in running-specific prostheses. Transtibial amputee sprinters try to maintain optimal impulse by controlling the range of hip joint motion and the extension speed as alignment changes.

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The below-knee prosthesis "Rabbit" for track which was developed by introducing the method of the product design has the beauty of appearance evaluated, on the other hand some people have had deep-rooted criticism against functionality as impression. Changes of impression evaluation of Rabbit to ver.4.0 (2013) which played an active part in the international match from ver.1.0 (2009) of the first stage are followed.

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The use of materials such as carbon fiber, titanium, and graphite has provided added strength and energy storage capabilities to prostheses while decreasing the weight of prosthetic components. Today, carbon-fiber running-specific prostheses (RSPs) are the most popular for elite running and jumping events. RSPs with energy storing capabilities have attracted individuals with lower extremity amputation (ILEAs) to running as a form of exercise and athletic competition, and allowed ILEAs to compete at levels never before achieved. Thus, improved understanding of running mechanics in prosthetic sprinting has aided the development of more effective sprint training for amputee sprinters. However, spatiotemporal parameters of amputee sprinters during 100- and 200-m sprints are largely unknown. Recently, we constructed Database for Biomechanical Analyses of Amputee Sprinters (DBAS) from the publicly available internet broadcasts of 56 races (n = 539). The DBAS includes several information about competitions, anthropometric profile, spatiotemporal parameters and type of RSPs in each athletes. In this study, we introduce normative data for spatiotemporal parameters of amputee sprinters during 100- and 200-m sprints and propose its future applications.

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Blind bowling is known as one of the popular sports for the visually impaired people in Japan. They can enjoy the bowling with sighted assistant who tells information of number of remaining pins, a ball trajectory, and a game score, etc. Bowling is such a well-adapted sports for the visually impaired people though, naturally the players want to know all of these information by themselves without any help. To fill this need, a system which detects remaining pins using image processing was developed as a first step. It is composed of general equipment like a video camera, a computer, a wireless switch and a wireless bone conducted headphone. Composing by general equipment allows target user to use the system easily in the future. The system speaks the number of remaining pins with speech synthesizer automatically and immediately after throwing. Several tests of using the system by severe visually impaired players gave useful feed backs and the system was improved. These test showed that the system works well and is useful and helpful for players. Addition to the results, unexpected advantage was discovered. Using this system, bowling game become more enjoyable for the blind player since they can acquire information of remaining pins not only of themselves but also of other players. They can share each delight result like Strike or Spear, and even blind player make an advice to other player. It can be said that the system successfully support blind players with enlargement of joyfulness of bowling.

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The aim of this study is to establish the method for improving the performance of body motion analysis by inertial sensor. The position vector must be measured before the experiment in the previous studies using inertial sensor. In the previous study, we developed the estimation method for the position information of the attached sensors. The method estimates the position vectors from the accelerometer to the joint position by the centrifugal and tangential accelerations included to the accelerometer output. This method is established by the Extended Kalman filter. The nonlinear state equation consists of the relational equation between the Roll-Pitch-Yaw angles and the angular velocity, and the position vectors from the accelerometer position to the joint position, and the measurement equation consists of the rotational matrix from the sensor coordinate to the global coordinate and the gravity acceleration. Furthermore, we extended the method for estimating the inclination parameter of body shape in this study. We conducted the measurement experiment to confirm the performance of the method by using the experimental setup installing the rotary encoders and attaching the inertial sensor system. We estimated the 3D posture by the sensor fusion compensating the effect of centrifugal and tangential acceleration established by the previous study. The calculation of centrifugal and tangential acceleration is used to the estimated position vectors and the inclination parameter. The estimated 3D posture showed higher accuracy than the 3D posture without compensation. The method can be used to the development of more simply motion measurement method and the improvement of accuracy in the motion analysis by inertial sensor system.

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The aim of this study is to establish the method for the accuracy improvement of joint torque estimation in body motion analysis by wearable sensor system. The wearable sensor system consists of the wearable motion sensors and the wearable force plates, and the system can measure the 3-axis angular velocity, the 3-axis acceleration and the 3-axis magnetic field in the body segment (Upper body, lumber, femurs, lower thighs and foots) and the ground reaction force. The 3D rigid link model is defined for the joint torque estimation, and the joint torque (Lumber spine, hips, knees and ankles) is estimated by the inverse dynamics analysis. We established the method for the accuracy improvement using the Unscented Kalman filter combining the human body structure and the Newton-Euler method. We conducted the measurement experiment using the wearable sensor system, and we calculated the joint torque by the traditional method and the joint torque by the proposed method. The joint torque estimated by the proposed method and the force plate values were showed the fitting results.

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Among high speed swing motions in sports, motion dependent term, which is a dynamics characteristic of multi-body system and is consisting of product sum of angular velocities of individual segments, is the great contributor to generating the tip speeds of hitting tools or distal body segments prior to the times of impact or ball release. Therefore, in order to develop a feedback system for improving the performance, it would be efficient to show speed generating mechanism as well as kinematic and kinetic information to players during immediate feedback. The purpose of this study was to develop a portable analysis system using inertial sensors to evaluate racket head speed generating mechanism during swing motion with consideration of joint torque generating types for immediate feedback in coaching field utilization. Two types of inertial sensors, such as gyro sensor and accelerometer, were used in the proposed system. The gyro sensors were attached on the upper trunk, upper arm, racket, and distal end of forearm segment. And the accelerometers were attached on the known location of upper trunk and racket. The sensor outputs were simulated from experimental data of tennis serve motion collected with a motion capture system (Vicon-MX, 12-camera, 250Hz). The error between estimated and measured accelerations was minimized to identify 12 parameters of initial coordination system of the segments by using function of fmincon (optimization toolbox, MATLAB, Mathworks Inc.) with an object function which minimizes the norm of the acceleration error. By solving the equation relating accelerometer sensor outputs to gyro sensor outputs with consideration of geometric constraint relationships in terms of acceleration, we can obtain initial orientation of individual segments, and can calculate motion data using the initial orientation, gyro sensor outputs, and accelerometer output of the upper trunk. The results of dynamic contribution analysis obtained from the estimated motion data show almost good agreements in terms of head speed generating mechanism.

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When a driver rides on a skateboard, to support the posture control is important for comfortable riding. To achieve it, a human body dynamics model is needed. In this study, we discuss mechanical modeling and identification of the posture control parameters during standing. We assume that the mechanical model is given by a simple rigid-body and posture control is determined by delayed feedback of the angle and the angular velocity of the rigid-body. To estimate the feedback gains and the delay time of the posture control, impulse response test and step response test were implemented. Center of mass (COM) and center of pressure (COP) were measured by motion capture and load measuring device in the tests. Since estimated parameters use to be a wide range of scatter in general, we focus on that characteristic root of COM and that of COP are common in the system. So, we propose a way to estimate the posture in control parameters in two processes. First, we calculated characteristic roots from COM and COP wave of an experiment by fitting using least-square-method. Second, we estimate the control parameters by comparing coefficient of two characteristic equations. As a result, we solved the problem of the parameters scatter in analysis of the impulse response test.

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The objective of this research is to develop a system which enables athlete swimmers and coaches to understand swimming motion in their training easily. Coaches will be able to grasp visually the real time situation of the swimmer with this system. This system is composed of an analytical PC, acceleration Sensor and information display unit. In this system, the analytical PC is located on poolside, and coach simply watches the software screen. Information display unit is installed in bottom of pool. The swimmer wears a tri-axial acceleration sensing unit. And this unit continues transmitting their acceleration value to PC in real time from water by wireless communication. PC analyzes pitch information, estimated velocity and assist information from this acceleration value. From this pitch information, coaches can grasp the state of the swimmer details such as estimated speed and time of each stroke of the swimmer. This is because a PC finds the correlation between acquired data in real time which every 1 acquires acceleration values and comparison data. Velocity estimation information is found by integrating acceleration. And PC converts these information into graph and definite advice, then displays the result that understandable visually. From the above, this system performs coaching assist of swimming race in real time.

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On machine manufacturing, not only the technological advance but also the coupling behavior between a machine and a human body are demanded in recent years. It is therefore necessary to think about machines and human beings as one system. In such a background, numerical simulation methods, called digital human, are often used for a design and an evaluation and are researched in recent years. The digital human is an effective simulation method reproducing physical behaviors. The purpose of this study is to construct a dynamics model for human whole-body movement having the simplicity which could apply to multi-degrees-of-freedom model. Then, as an example of the model, the seated human model was studied which reproduces physical behavior of human being getting on a vehicle. Moreover, by proposing sequential trajectory planning, the seated human model was improved in a model which could deal with disturbances. When the seated human received a disturbances, the simulation s' trajectory was planed again. And the human body dynamics model had 20 rigid links with 43 degrees of freedom in the whole body.

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The first purpose of this study considers the degree of burden and degree of fatigue for each muscle by angular momentum of around the lower limb joints during running of the people. This angular momentum of the each muscle represents the severity of muscular exercise. The angular momentum of each muscle worked to produce the driving rotation power around joints. At last, for the final purpose of this study we verify the usability and value of the proposed method from those consideration results. In this case, the muscle mathematics model of the 3D frame model of the lower limbs that was used for inverse dynamics analysis and inverse kinematics analysis is Hill type model. In the future, the usability of the proposed method is verified by comparing with conventional method for evaluating the degree of burden and degree of fatigue for each muscle of muscle activity.

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Biomechanical analysis of the musculoskeletal system has become an important issue in human motion analysis. The aim of this study is to create an optimal landing motion using musculoskeletal model and to clarify a dynamic characteristics of landing motion. The human body using in this study is modeled as a system of rigid bodies in the xy-plane. The model consists of eight rigid links and seven joints including 19 Hill-type muscle models. The optimal landing motion was created by Multi-Objective Genetic Algorithm with three cost functions. We obtained Pareto optimal solutions and visualized each landing form and time history of joint angle. Then, we performed the experiment that landing task by two male subjects. The position of body parts and surface electromyogram was measured by a motion capture system and a wet type electrode to examine biomechanical characteristics. Finally, we evaluated biomechanical behavior of landing motion and verify the validity of the proposed simulation model.

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The purpose of this study was to quantify the dynamic contribution of racket side arm muscles in consideration with muscle contraction types in tennis serve motion. In order to assess dynamic contribution of individual muscle forces, a musculoskeletal model with 144 muscle elements was constructed by using the SIMM software, and the contributions of muscle forces of the racket side arm to the racket face speed at impact and to the shoulder joint angular velocity were obtained from a dynamics analysis based on the equation of upper-body motion with consideration of the generating factors of the motion dependent term. Male collegiate athletes, participated as subjects in this study, performed first services. Trajectories of markers on the body and ground reaction forces were measured with VICON-MX system and a force plate, respectively. The results obtained in this study indicate that 1) the concentric muscle torque of clavicle part of deltoid and subscapularis via shoulder internal/external rotation axis was great contributor to the racket face speed, 2) the shoulder external rotation angular velocity inducing eccentric internal rotation torque was generated by concentric muscle torque of clavicular part of deltoid, infraspinatus, teres minor, and coracobrachialis and by eccentric muscle torque of clavicular part of deltoid and coracobrachialis, and 3) contributions of concentric components of individual muscle forces are greater than those of eccentric components. It must be noted that the results depend on the object function and parameters used in the musculoskeletal model.

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When analyzing or viewing sports movements on video, users require step-by-step or slow motion. But network video such as YouTube or any streaming does not have such capabilities; these only handle play or pause. This article explains several new methods to achieve such sports specific video playback; step-by-step, trick plays, multi-cameras, efficient thumbnails, and image processing for streaming videos. For trick plays and multi-cameras, the author invents "serialize method" to handle multi videos on server. Also the author invents "non-liner thumbnail method" to access important scene quickly and browse scene accurately for thumbnails. These methods make users to access network videos more flexible and precise like these are the local files.

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The purpose of this study is to promote the new community sport support including establishment of comprehensive community sports in university using the specialties of university's professional education for find the concept of a new sports club. In order to perform this purpose, we focused on the following two points: (1)Construction of a supporting system which capitalize on the specialty of the faculty of technology (information system engineering). (2)Construction of public offering type leader information management system for athletics executive officers and retirement teachers based on cooperation with administrations. Firstly, we reported training contents to participant's parents in swimming class and tennis class and sent the plurality of contents (movies of lessons, motion analysis movie, portfolio) by building LAMP system. According to questionnaire answers from the user of this system, it was understood that their evaluation to this system was high. (More than 80% answered "It is attractive".) Secondly, we constructed a management information system to register some instructors in order to increase in the number of the community sports. Currently, 42 instructors registered in this system. In addition, age of the registrant is a wide range and they can teach various competitions. Therefore, this system may contribute to solve the lack of leaders. Research as a result, the possibility of new comprehensive community sports club establish was suggested by making use of expertise of the university.

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The purpose of this study were to investigate the influence of the water flow and wave against the supine floating(called "Tyakuiei" or "Uitemate" in Japanese) using the heart rate variability as an index of the autonomic nerve system activity and amylase value in the saliva and to have a resources for the water rescue and survival research. After 3 minutes supine floating in still water, subject tried to perform that floating with exposure on the artificial water flow or wave during 3 minutes. Between the both experiment, subject took a break for several minutes. The wavelength was almost 2.0m and wave height was 0.1m. Average heart rate was not much difference between still water and water flow (wave). High frequency of R-R wave interval in the electro-cardiograph in wave was higher than that in still water. Amylase value in water flow was higher than that in still water.

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It is reported that drowning accidents occur when the person is fully clothed. The victim should take the back float position, because comfortable for breathing. However, it is considered to be feeling the discomfort by water, physiological changes will occur. In this study, the degree of discomfort is expressed by the heart rate of the victim. The experiment was carried out in the swimming pool at a water temperature of 10.5℃ and a room temperature of 14.2℃. Three subjects were selected. They continued to keep the back float position with fully clothes including the sweater and the rain jacket on the surface of water. In addition, the temperature loggers and a Holter monitor were attached to the subject. The duration of keeping the back float position on the surface of water was 15 minutes. The temperature and electrocardiography were analyzed by regression analysis. The heart rate for all subjects increased in a moment prior to the decrease with decreasing the temperature near the surface of the back. The high heart rate continued for 1 minute and then it decreased. First increasing is thought to be a result of discomfort of the subject who feels cold water at his back. On the other hand, decreasing following first increasing is thought be a result of promotion of the venous return by the water pressure, accompanied with habituation for cold water. These results suggest that discomfort of cold water may be a factor for the breaking the back float position.

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In this paper, we simulate an oblique collision between a golf ball and a metal block by LS-DYNA. Two kinds of a spin ball and a distance ball are used in the simulation with changing loft angle of the block, which is 15 degree, 30 degree and 45 degree. The balls are modelized by 3 piece ball, which consists of a core, a mid and a cover, and their young's moduli are determined from compression test of the ball and the block. The frictional force, the spin rate, the shooting angle, the shooting speed of the golf ball and the slip condition between the ball and the block are examined by the simulation. As a result, the difference of the spin ball and the distance ball are discussed on the frictional force, the spin rate, the shooting angle, the shooting speed and slip condition.

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The purpose of this study was to investigate how the surface conditions (wet or dry, smooth or rough surface) of the metal baseball bat affect the batted ball characteristics of rubber-ball baseball. A bat swing robot was used for generating bat-ball impact. The experimental results showed that the wet surface of the normal metal baseball bat makes the ball slippery and it would cause worse batting performance. To prevent the slipping phenomenon, an additional bat was also tested. By knurling the surface of the additional bat, it inhibited the larger slip of the ball even under the wet surface condition. Furthermore, a questionnaire revealed that most rubber-ball baseball players wipe up water drops from the bat surface, which corresponded to the experimental results.

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This sheet deals with the middle speed impact experiment with air gun. We classified slow speed, middle-speed, fast-speed impact velocity. Currently, high-speed and low-speed experiments have been conducted. Middle-speed experiment has not been conducted so much. Middle-speed experiment is difficult. The reason is because cannot ensure the accuracy of medium-speed experiment. In this study, we examined the middle speed experiment using an air gun. We fired in the horizontal and vertical directions in order to check the speed and precision positional accuracy. As a result, We have determined that it is possible to middle speed experiments using the air gun.

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Badminton shuttlecock is light in mass (approximately 5.2g), with a highly specific air resistance. For professional badminton players, the highest initial speed of the shuttlecock by a smash shot exceeds over 80m/s, which is the fastest speed in all ball sports. Generally, it is extremely difficult to get the shuttlecock to speeds of over 30m/s with a launching machine without breaking the waterfowl feathers. In this study, a shuttlecock launching machine using two turn rollers for badminton exercises has been developed with a new launcher mechanism. In addition, a continuous launcher system which is able to discharge the 12 (maximum 96) shuttlecocks continuously at intervals of 1.5 seconds was designed. The two rollers type badminton machine can launch the shuttlecock at initial speeds of up to 81.8m/s, with a maximum flight distance of over 11m. The standard deviation of the shot and lateral directions are approximately 0.34m and 0.12m, respectively. The launching performance of the developed badminton machine has a performance far exceeding almost any commercial one. The badminton machine can be used for various kinds of difficult exercises by professional badminton players.

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It ran 2920km making the chain sprocket for the bicycle for trial purposes with 3K carbon fiber bunch and being include the public road in ten months of three years at rain. The chain made of the carbon fiber bundle reinforced plastic sprocket, the addendum was not a loss and was worn out. The measurement of the consumption calorie measurement and the pedal output became possible by installing the heart beat meter and the pedal power meter in cycle computer with the GPS function. It made comparative study with extra super-duralumin A7075 sprocket for the performance evaluation of the CFRP sprocket. The pedal rotation output increased by an increase of the average speed on a smooth road, the average speed exceeded, the pedal rotation output of CFRP exceeded that of A7075 at 10 km/h or more, and the pedal rotation output of the CFRP sprocket was 50% increase in 25 km/h of it of A7075. The pedal output increased by an increase of the average speed in the CFRP sprocket and the A7075 sprocket on non-pavement road and the difference was not seen by both. The CFRP sprocket was a constant pedal output in the climbing up the slope examination of 9% inclination regardless of the average speed. However, a pedal output high for the average speed to decrease in the A7075 sprocket was needed. The CFRP sprocket is suitable for climbing up the slope.

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