A curling stone's motion is controlled by the frictional interaction between running band and pebbles which lying down on the surface of the ice. The curling sweep is considered as a warming action to heat up the surface. Thereby, it is able to change pebble's shape, resulting in the decrease in the ice friction coefficient. Wherefore, the motion of curling stone will be became easier and a Measurement system are being established to inquiry and also measure the human's exerting force which have affected on the ice's surface during sweeping.

Side-step cutting maneuvers (SS) is one of crucial techniques in ball games. Since previous studies reported that running speed increase during the cutting maneuvers in the ball games (e.g. soccer), the purpose of this study was to quantify the functional roles of support leg joints during accelerating phase of SS. A male participant was instructed to do 90-degree SS under two types of approaching velocity conditions (i.e. 3.5m/s and 5.5m/s). Forty-seven reflective markers attached on the body and ground reaction force (GRF) of support legs were measured with Vicon-MX motion-capture system and force platform, respectively. The dynamic contributions of support leg joint torques, at first step (first cutting leg: CL1) and next step (CL2) during cutting maneuvers, to the generation of GRF were quantified by using dynamical force equation regarding 15-segment-linked whole-body system. The results obtained in this study show 1) regardless of the approaching velocities, the extension torque at knee joint of CL1 play a role in braking along the approaching direction, and the roles of the ankle plantar flexion torque of CL1 and CL2 in addition to the eversion torque of CL1 were braking along the approaching direction as well as propulsion along the cutting direction, 2) the total time integration of contributions, induced by the support leg joint torques of CL1, to the propulsive force along the cutting direction under the condition of 3.5m/s were larger than that of 5.5m/s, and 3) the inversion torque at ankle joint of CL2 play a role in braking along the approaching direction and propulsion along the cutting direction.

We have discussed the applicability of assisting devices using gyro-moment to sprint running for a pendulum model with an oscillating slider crank mechanism. In this paper, the proposed assisting device is attached to user's body and supports sprint running. Experimental results are shown that the devices makes running speed faster, such as the running rhythm is accelerated and the running stroke is improved.

In this study, an inverse dynamics analysis method considering swing leg motion was constructed only by using some wireless motion sensors.(WMS) First, it was confirmed that the acceleration data by the WMS agreed well with the one by the 3-dimensional motion analysis system. Then, the method to separate the hip joint reaction force obtained from the equation of motion of the body into the support leg and the swing leg and to identify the ground reaction force was constructed, i.e., the top down approach considering swing leg motion. For the actual running data, the ground reaction force was identified, and it was concluded that the result agreed well with the one by using the force plate. The method constructed in this study, therefore, is concluded to be applicable for the actual application.

Nordic walking, or walking with poles, is an effective aerobic activity that uses the whole body. We analyzed the acceleration data of the poles by monitoring sensors attached to the tips and grips of the poles. Using this system, we collected and analyzed data from both experts and beginners. Results from the frequency analysis of the acceleration indicated that there were two or more peaks in the data from the experts, while there was only one peak in the data from the beginners. Moreover, we found differences between the experts and the beginners in the timing of both the poles and the feet; these differences will be useful in differentiating between experts and beginners. We investigated the effects for indications on the features for the pole works. Using the results, we developed a program automatically to analyze the data and indicate the features by sounds during the pole work.

We examined whether a swing on gymnastic rings can be performed by control for achieving an inter-joint coordination. The swing in the sagittal plane was modeled by a three-segment model with two degrees of underactuation. The coordination was modeled by a linear relation among joint angles as a virtual holonomic constraint. The controller was constructed by the partial feedback linearization. The simulation results showed that the model had solutions similar to steady swings in gymnastics, and the swing amplitude can be increased by switching two inter-joint coordination.

The “Sway” is one of the important techniques in ballroom dancing and also is seen in many other sports such as skate, ski, running, and sports with vehicles etc. According to the authorized syllabi of the ballroom dancing, the sway is defined as the inclination of the body away from the moving foot and towards the inside of the turn. However, there are some questions to this definition of sway. which is cleared in the present analysis and a more precise classification is given with mechanical analysis introducing a new concept of inclination and bending. First, basic mechanism of the sway is explained as the balance of the inertia force of the dancer's body and the force exerted by the inclination of the body using an inclined one bar element model. Mathematical functions are introduced to simulate the translational body movement and the amount of inclination in the sway is estimated by the analytical solution. Further a two-element model is introduced in the present analysis which includes both the inclination and the bending effects. This model explains the control and stability of the sway and to match the function of the force to explain the swing movement and the function of force by the sway analysis. The sway process is classified in the three stages, and the change of the inclination and bending angles with time is demonstrated for each stage with taking examples for some figures.

In this study, we focus on the suppression of essential tremor in human limb using a low cost and less burdensome vibration damping device. The tremor is observed in most human arms even at physically well condition that is derived from excessive stress or chills, therefore, it may cause anyone bad effect on precise operation such as welding and surgery. In this work, experiments are performed where the simulated microscopic surgery is imposed on subjects whose fingers are equipped with the dynamic absorber attenuating the tremor in their hands. The absorber is designed and tuned to a specific frequency based on the preliminary measurement result of tremors. Subjects were asked to grip a needle having a relatively small diameter using tweezers, and were also asked to insert it in a needle with a larger diameter. Tremors were measured while the subjects keep the tip of the needle in place. It is shown that the dynamic absorber can attenuate vibration in human fingers.

An interclass relay race was optimized. The objective function was the goal time. The shorter goal time is better. The design variables were the running markings (The receiving runner begins his/her run once the incoming runner reaches the marking.) and the runner order. The constraint is that the baton must be passed from one runner to the next in the exchange zone (20m zone). The optimization was carried out by using the genetic algorithm. It was found that the goal time becomes shorter by optimizing the running markings and the runner order. The baton pass should be made from the faster runner to the slower runner, and vice versa, when there is a huge gap between the running ability for each runner in the relay team.

The purpose of this study was to clarify balance maintenance mechanism during support phase in running. The functional roles of support leg joints and torso joints were analyzed by quantifying dynamic contributions of the joint torques to the generation of angular velocity vectors of the ankle, hip and torso joints in the frontal plane using the equation of whole-body motion. A male runner participated in this research and ran at the speeds of 4 and 3.5 min/km. The trajectories of 47 markers attached to the body and the ground reaction force of the support leg were measured with VICON-MX system with a force plate. The results indicate that 1) the contributions of individual joint axial torques to the angular velocities whose axes are normal to the frontal plane are canceled so as to reduce the angular velocities, 2) the angular velocities are induced by joint torques whose axes are normal to not only frontal plane but also sagittal and horizontal planes, and 3) the balance maintenance mechanism would change when running speed and foot strike pattern change.

In this study, three-dimensional homogeneous finite element analysis consisting of hyperelastic beams were conducted to predict macroscopic mechanical characteristics of open cell polyurethane foam while considering its microscopic structure. Homogenization theory was applied to original finite element analysis code, and unit cells for simulation were assumed to be subject to periodic boundary conditions. The polyurethane matrix was assumed to be represented by incompressible hyperelasticity. The material parameters for the polyurethane matrix were identified with the tensile loading test results. To verify the effect on mechanical properties given by the structure of unit cell, cubical unit cell model and truncated octahedral unit cell model were proposed. Furthermore, compression tests on polyurethane foam with various relative densities were conducted to verify the applicability of the analysis. The analysis results had good agreement with the compression test results.

In this study, the effect of microscopic structures of foam rubber were investigated numerically. A 2-dimensional finite element analysis code and a 2-dimentional homogenization finite element analysis code of the hyperelastic material were developed, respectively. The incompressible hyperelasticity in the total Lagrangian finite strain framework was applied to both of the general FEM and the homogenization FEM codes. The reason of which foam rubber were used widely, is that it has some advantage properties. But effect of microscopic structure on macroscopic stress-strain relationships is not evaluated enough in the point of engineering material design. To clear this engineering issue, compression loading tests of rubber specimens which have periodic geometrical holes were conducted to evaluate the effect of periodical structure on mechanical characteristics. Relative density of natural rubber specimens were 42%, 56%, 72%, 80% and 86%, respectively. The biaxial tensile tests of rubber sheets which were made from same natural rubber used in compression loading tests were conducted to identify material coefficients of the elastic potential function of the hyperelastic matrix. The stress-strain relationships given by compression loading tests of the natural rubber specimens were simulated by the finite element analysis programs with the general boundary condition and the periodic boundary condition to investigate the applicability of homogenized method to foam rubber.

The competition properties of a table tennis game are hitting the ball with a racket and bouncing to the court. The ball speed and spin influence the orbit of the ball and contribute to the game score. Following the fact that the diameter of the ball used in a competition was changed from 38 mm to 40 mm in 2000, the difference in the rebound performance based on the ball diameter was studied by some researchers. However, there are few studies about the performance evaluation of the rubber sheet for table tennis rackets. In this study, in order to evaluate the rebound performance of the commercial rubber sheets, repulsion speed and of spin rate are measured by the authors in the collision experiment using the table tennis machine. The performance of four rubber sheets was compared according to the catalogue specifications from two companies that made them. In addition, we experimented with changing the ball speed from 20 to 70 km/h and the spin rate from 0 to 4300 rpm by the machine. From the experiment results, it was found that the coefficients of restitution in all rubber sheets decrease as the incidence ball speed is faster. Also, the coefficient of restitution was influenced by the racket angle (incidence angle). The speed and spin rate in the two types of rubber sheets had the same rebound performance values in these catalogue specifications, whereas other types of rubber sheets were different from those in the catalogue.

Polyvinyl alcohol hydrogel (PVA-H) is proposed as a candidate material for an artificial cartilage. It is said that PVA-H is biocompatible material and is also said that fluid film lubrication is achieved by squeeze film effect because of the high moisture content. Consequently, PVA-H is expected to achieve low friction and to reduce wear of prosthesis simultaneously. According to our early study, the friction of PVA-H increases as the sliding cycles increase. In this study, friction experiment with intermittent loading system is conducted to clarify the effect of lubricant film between PVA-H and glass prism. The contact area between PVA-H and mating prism in lubricant is also estimated.

Experiments have been carried out to examine the effects of resonance frequency and e-ion, that is, free electron, emitting from resonite radiant materials developed by using the polar crystal metals involved with granite on thermogenesis and warm keeping of human body. The acquisitions are as follows that, (1) The partial emissivity of resonite radiant materials at resonance frequency is approximately 0.94 and this may demonstrate the excellent resonance effect, that is, hyper thermic effect to human body as external factor and also demonstrate the excellent thermogenesis as internal factor caused by elements such as free electron . (2)Since the oxygen adopted in our body through lungs is not oxygen but oxygen minus ion (O₂^-), the repulsive force operates among red blood cells. So, it is possible to prevent the adhesion among the red blood cells. This fact indicates that the smoothing flow of blood may be established. The repulsive force operated between a pair of the red blood cells may be approximately 1.15nN.

In this research, we aim to visualize the heat and flow field around the athlete model using numerical fluid dynamics analysis (CFD), and examine the running attitude and the heat and aerodynamic performance around the athlete. In this study, we use general-purpose thermal fluid analysis software STAR-CCM + to obtain heat and aerodynamics around the athlete by numerical analysis due to the difference in posture during running. Four thermal analysis patterns and three aerodynamic analysis patterns were carried out. As a result, the difference in the running attitude causes a difference in the surface temperature of the athlete. By setting an angle to the running attitude rather than being perpendicular to the ground, the amount of heat transfer decreases and the surface area average temperature increases. On the other hand, the aerodynamic performance decreases with increasing angle of the upper body. Further, the temperature around the athlete model is lower in the traveling posture positioned behind the traveling posture where the arm position is located at the front.

In this research, with respect to Back-Shot-Beauty-Exercise, changes in the epidermal temperature of each part of the body over time are measured, and the relation between the Back-Shot-Beauty-Exercise and the body temperature is experimented. the Back-Shot-Beauty-Exercise Although body temperature temporarily decreased after performing the Back-Shot-Beauty-Exercise, the body temperature gradually increased from 70 minutes after the start of the exercise (40 minutes after the exercise end), the average body temperature of the whole body increased from 0.2°C to 1.4°C did. Especially the body temperature of the hands and ankle was found to rise greatly. It can be said that the fact that the body temperature of the hand is largely rising can be predicted to support the impression that it will shine after the Back-ShotBeauty-Exercise. In addition, since the body temperature at the lower body temperature and the body near the toes is rising, the blood flow of not only the arteriovenous vein but also the capillary blood vessel can be expected to increase.

To design comfortable clothing in hot environment, heat and moisture transfer in human-clothing-environment systems considered sweating responses must be evaluated. In this study, the regional sweat rate and evaporation was measured using wearable hygrometers and the computational fluid dynamics (CFD) analysis in clothing microclimate based on the measured value was conducted. The results of the sweat evaporation measurement were validated by body weight loss. To estimate the air temperature, velocity, and relative humidity distribution in and around clothing, the simplified cylinder model for torso of adult male wearing single-layered clothing under natural convection was examined. The results of CFD analysis showed that the air tended to rise and drift toward a neck slit by human heat generation. Influential factors on moisture transfer characteristics of sweating at abdomen were clarified. These results may become useful database for clothing design and prediction of thermal comfort.

We prepared an artificial leg jig and the joint torque measurement system for the purpose of evaluating the knee joint torque of sports spats. The leg jig was made of polymer foam and reproduced the shape of the leg of the 3D-CG model of the human body. Then, the knee joint torque produced by the sports spats ware measured by giving a bending motion to the knee portion of the artificial leg jig. Next, the knee joint torque generated during the knee bending motion of the sports spats was estimated by numerical simulation. The fabric materials for sports spats show anisotropic stress strain relations and stress softening in mechanical properties. Therefore, an anisotropic hyperelastic model was applied to numerical simulation. Then, we supposed that the strain of sports spats on human body during running was reproduced using 3-dimensional computer graphic model. As a result, stress and strain distribution were calculated, and knee joint torque produced by sports spats during running was calculated. As for sports spats, it was confirmed that as the joint angle became smaller, torque was generated in the direction to extend the knee, and it showed the possibility of considering it as a support effect to the knee of sports spats.

In this paper, for the purpose of transmitting the warning information to the player in the hearing impairment sports, the body placement location of the vibration motor used to transmit information was considered by paired comparison. In the experiment, the vibration motor was placed anterior carpal region, upper arm, chest, and abdomen, and it was conducted in 7 grades evaluation based on 5 evaluation items - understandability, speed of perception, discomfort, titillation, and resound. In addition, comparison with the conventional information transmission by visual was also conducted. As a result of the paired comparison experiment, it was found that the information transmission method by the vibration is more perceptible than the visual method and that the upper arm is suitable for the body placement location of the vibration motor.

Fifth metatarsal stress fracture occurs frequently in soccer. Many researches about occurring the injury have been conducted, however, they mainly focus on structure of feet or plantar pressure under fifth metatarsal bone. Therefore, the value and occurring mechanism of stress on the bone has not been clear. In this study, we conducted finite element analysis of movements in soccer using a foot finite element model and clarified stress at fracture position. Then, some mechanical parameters which have correlation with stress were found. Firstly, we conducted subjects experiments of 8 movements which occur frequently in soccer to define boundary conditions for finite element simulations. Foot motion, reaction force and plantar pressure distribution of 2 Subjects were measured in the experiments. After that, finite element analyses were conducted in cases of 3 movements, which are inside step, acceleration, cross step, by inputting measured data as boundary conditions for the foot finite element model. As a result of simulations, max principal stress at fracture area showed higher in acceleration case. However, considering duration time, the inside step case showed the highest value in 3 movements. In addition, it was found that each movement had different physical parameters which showed high correlation with stress at the fracture area; forefoot internal rotation, plantar pressure under fifth metatarsal bone or thenar.

Functional electrical stimulation (FES) cycling is one most of rehabilitation to improve muscle enhancement and hypertrophy by electrically stimulated pedaling motion using FES cycle. Generally, many FES cycling use recumbent-trike type bicycle, however it cannot adjust crank position. In this study, we evaluated difference crank position of FES cycle for voluntary motion using musculoskeletal model. FES cycle used a wheelchair detached FES cycling unit developed by previous studies. For musculoskeletal analysis, we developed a pedaling measurement system to obtain the change in pedal reaction force and constant motion during cycling. The effects of the crank position on muscle force of lower limb muscle of healthy subjects were evaluated. As a result, maximum muscle force obtained small value when width away position from based position, and large value when height away position in rectus femoris. Therefore, adjustments of crank position suggested that realize highly effective rehabilitation in FES cycling.

Fall accident occurs in daily life. But especially in elderly, it leads to serious injury. Therefore the prevention of fall injury is necessary. Previous studies analyzed fall injuries using human body model and finite element analysis, but these studies are related to after-fall phases. Other study evaluated each person's protective motion that is occur during the fall. However, elderly's fall occur because of the decline of the protective motion skill due to the decline of motor function. Therefore to improve each person's motor function, evaluation of protective motion skill is necessary. In this study, we adopt Ukemi (the technique used in Judo) as protective motion and evaluating the skill of Ukemi by comparing Judo expert and beginner. The experiment to measure the Ukemi motion was conducted using motion capture system. The subject were 10 Judo experts and 10 beginners. The motion capture data was inputted to Opensim, a musculoskeletal model, and then converted to joint angle data. To compare the motion, the start and end time of Ukemi is extracted using change point detection method. And then feature of motion is extracted using principal component analysis. As a result, we found that expert's motion is shorter than beginner. Also we found the difference of Ukemi motion between expert and beginner. Further study is needed to evaluate each person's skill more precisely and construct the method to improve protective motion skill.

The purpose of this work is to understand the mechanism of manipulating ball spin during baseball throwing. A throwing motion of arm and fingers were captured using motion capture system to understand the control of linear and rotational movement of ball. In this article we investigate how to overcome the interference of control of linear and rotational movement of it. We used singular value decomposition to identify accurate ball orientation and optimization to estimate the center of ball.

Judo has been compulsory at junior high school in Japan since 2012. However, judo has a higher mortality rate than other sports, and countermeasures are urgently required. The main cause of death accidents in judo is acute subdural hematoma (ASDH). ASDH is caused by the brain moving in the cranium due to a strong impact on the head and rupture of the bridging vein connecting the brain and skull. The purpose of this study is to examine the head protective equipment which can suppress the variation range of the head angular velocity at the time of head collision, paying attention to the head angular velocity from the viewpoint of suppressing the rotation of the cranium. As a result of changing the spring constant and the damping coefficient of the protection material, the variation range of the head angular velocity became the minimum in (k , c) = (10⁴ N/m , 10³ N ∙ s/m). Furthermore, as a result of fixing the spring constant to 10⁴ N/m and optimizing the damping coefficient, at c = 179.47 N ∙ s/m, the variation range of the head angular velocity became the minimum. Therefore, the optimum combination of spring and damping coefficients is (k , c) = (10⁴ N/m , 179.47 N ∙ s/m).

Shock attenuation property of sports surfaces is especially important not only for the athlete's performance but also for injury prevention. To evaluate the properties of the sports surfaces, some sports governing bodies often adopt friction tests and shock attenuation tests to determine the horizontal and vertical characteristics, respectively. Although the diagonal impacts are often observed in athletic sports, shock attenuation test treats only the vertical impact test. Therefore, we developed a two-dimensional impact test device for examining the two-dimensional cushioning characteristics of sports surfaces in previous studies. To produce a simultaneous two-dimensional force against a test specimen, we incorporated a parallelogram linkage in the measuring system. The weight is dropped onto the upper side of the parallelogram linkage with various height and various initial angles. Initial angle controls the ratio of vertical/horizontal impact forces. In previous studies, FR (Force Reduction) values are calculated from experimental un-cushioned and cushioned forces for evaluating the shock attenuation properties. Additionally, to evaluate the maximum deformation during the impact, a biaxial accelerometer is attached to the sensor unit. Although FR values are simple and easy to calculate from the experimental data, it needs a vast cost because there are huge number of combinations of impact angles, magnitude of impacts and impact durations if the tests should be covered for various human activities. Therefore, in previous studies, we proposed the vertical viscoelastic model which can represent the behavior of sports surfaces during the impact for evaluating the shock attenuation properties. In this study, we propose the two-dimensional viscoelastic model of sport surfaces for evaluating the two-dimensional cushioning properties. Finally, proposed model can be used for estimating the impact forces from the experimental data.

Low back pain is one of the most major reasons for caregiving workers to leave their jobs. It is caused by a mechanical load acting on the muscles and the spine in the lumbar part. This paper presents a study aiming to develop a passive support wear that reduces the load on the lumbar part during a nursing care operation. In particular, the influence of the antagonism of the abdominal muscles is focused on in this paper to understand the mechanical effect of the support mechanism which is to be optimized to provide a support force from the abdominal side to minimize the compressive load on the lumbar spine. A rigid body model taking account of the muscular force of the abdominal muscles, the erector spinae, the support force is analytically examined to investigate the design requirements. It has been confirmed that the load on the lumbar spine increases due to the antagonism effect.

In many sports, collision with a ball or other player causes injury in a player. Therefore, protectors with hard outer shell have been widely used. Generally, hard protector has a layered structure, consisted by hard outer shell and soft inner shell. When a protector is subjected to a collision, the outer shell compresses the inner shell uniformly without local deformation, preventing excessive impact force to human body. In this study, a flexible protector having an outer shell hardening only under impact due to time dependency of elastic modulus of epoxy resin. To control the time dependency, a crosslinking density of resin was changed. Prototype flexible protectors were designed based on the time dependency of elastic modulus, and flexibility and impact absorption characteristic of the protector were evaluated.

Bicycles have been widely used in Japan. However, especially for younger people, bicycles are used in a setting that does not match their body geometry or riding environment. In our laboratory, we have analyzed the cycling movement using the pedal sensor developed and the three dimensional motion analysis system(Vicon). In the previous study, the influence of the lower limb joint moment and the lower limb muscle myoelectric value(EMG value) on the change in saddle height was investigated for sports bikes and Japanese city-cycle. In this study, the authors investigated the influence on the lower limb joint moment, EMG value, EMG timing of lower extremeties during cycling motion on sports bicycle(road bike), mountain bike, Japanese city-cycle, recumbent cycle, which are different riding posture(different trunk angle).

Injuries in elbow joints are frequently occurred in many sports, such as baseball, tennis and so on. Also in judo, many players in wide generations suffer from elbow joint injuries. Therefore, it is important to investigate the mechanism of elbow joint injures during Judo motion from mechanical aspects of view. In this study, the elbow joints of the period of growth were modelled and stress analyses were carried out to clarify the outbreak mechanism of the elbow joint obstacle. A 9-year-old bone specimens were used for modeling three-dimensional finite element models from head of humerus to the distal edge of radius and ulna. About Seoinage throw types, both forearm middle position and forearm outside rotation position were considered. For boundary conditions, caput humeri was fixed and a ulna was loaded for the forearm middle position and a radius and an ulna were loaded for the forearm outside rotation position. As a result of analyses, it is found that humeral epicondylus lateralis in the forearm rotation position was the highest for maximum principal stress. In addition, humeral medial epicondyle in the forearm rotation position was the highest for maximum shear stress.

In this study, we aimed to confirm objectively the change by wearing an insole with different thickness on the heel part. In addition, we aimed to examine whether human beings can understand that movement changes according to the thickness of the insole as human body sensation by reproducing the motion during the experiment after the experiment trial. The experiment participants were four healthy men in their twenties. I gave the experiment participants the full vertical jump. We set conditions that do not use insoles and three conditions using 15 mm and 30 mm insoles. The difference between the hip joint angle of the measurement trial and the reproduction trial was 14 degrees under the insole without condition, 11 degrees under the 15 mm condition, and 8 degrees under the 30 mm condition. In addition, the knee joint angle was 4 degrees under the insole without condition, 6 degrees under the 15 mm condition, and -12 degrees under the 30 mm condition. The error at 30 mm condition was the largest value.

The thoracoabdominal pressure to occur at the time of crowd accident has the risk to let a person lead to suffocation. This study tested slight pressure on healthy subject's thorax and abdomen. The pressure load up to 40 kg (thorax 20 kg, abdomen 20kg). Pressure loading time defined as up to 20 minutes. We inspected about breathing properties of low tolerance subject for the pressure. As a result, pressure load condition at the interruption of low tolerance group was in condition that load 20 kg on the thorax, and it was suggested that pressure on thorax load was the main factor of the interruption. In addition, vital capacity of low tolerance group by pressure load on thorax of 20 kg is indicated more suppressed than high tolerance group.

The purpose of this study was to clarify the characteristics of the attacking plays between midfielder (MF) and defender (DF) in Japanese J. League (JL). In order to achieve the purpose, we compared JL and German Bundesliga (BL), and compared the top 4 teams of JL with the bottom 4 teams of JL. The sample set comprised 40 matches: 20 BL matches (from the 2015-2016 season) and 20 JL matches (from the 2015 season), and 32matches played directly against the top 4 teams and bottom 4 teams of JL (from the 2016 season). A chi-squared test were used for statistical analysis. Our findings were as follows: (1) BL and the top 4 teams of JL had more scoring opportunities than JL and the bottom 4 teams of JL. (2) Compared with BL, JL had more goal-side DFs and fewer forward play. This was thought to lead to less scoring opportunities. (3) Compared with the bottom 4 teams of JL, the top 4 teams of JL had more forward play when there was no goal-side DF. This was thought to lead to more scoring opportunities.

The present study utilized physiological and neuropsychological indices to clarify the characteristics of intracerebral information processing in expert soccer players. A total of 26 university soccer players of different sporting levels (expert group: 13 subjects, sub-expert group: 13 subjects) participated in the experiment. As physiological indices, we measured event-related potential (ERP), electromyography reaction time (EMGRT), and reaction time (RT) in choice reaction tasks for actual play situations (4 vs. 2 maneuvering task). As a neuropsychological index, we used scores from the design fluency test (DFT), which is used for executive function screening. Results indicated no significant differences for P300 latency or amplitude for ERP in the choice reaction tasks. This demonstrated that there were no differences in the level of experience for the process to evaluate stimulation in the form of “what type of situation.” EMG-RT and RT were significantly shorter in the expert group than in the sub-expert group. This suggested that a marked difference in intracerebral information processing during decision making was the ability to accurately and swiftly execute motions (output). DFT scores were significantly higher in the expert group than in the sub-expert group. Similar to previous studies, this suggested that expert players had excellent executive function creativity. The above results indicate that the characteristics of intracerebral information processing during decision making by expert soccer players are the abilities to swiftly process response and motions for executing plays and having excellent executive function.

Recently, in addition to physical and skill training, mental training for athletes is increasingly important. Mental training encourages athletes to acquire psychological skills such as relaxation and emotional control with the purpose of demonstrating their abilities in competition settings. In particular, psychological tests to measure psychological characteristics are necessary for grasping the psychological state of individual athletes and verifying the effectiveness of training. However, psychological tests on a regular basis can be a burden for athletes. In addition, there is also a problem that the management and feedback of psychological data by questionnaires is burdensome for mental trainers in cases where subjects are a large group, such as a sports team. Therefore, this study developed an application that visualizes athletes' psychological data gathered through web questionnaires. In addition, we conducted an interview on the developed applications for coaches and athletes belonging to the sports team. Based on the results of interviews, the methods of psychological tests and feedback from the test results considering the competitors were discussed.

Until now, the save percentage has mainly been considered as an indicator for evaluating a goalkeeper's ability to defend. However, this measurement does not consider the degree of difficulty of the shots taken, thereby limiting its usefulness. Hirashima (2014) performed a logistic regression on 551 shots on target during the FIFA World cup 2010 to clarify the causes of difficulty for shot stopping and to create a regression equation to quantify the difficulty of each shoot stop. It will be possible to objectively evaluate goal keeper performance using this equation. The aim of this research is to evaluate the performance of the goalkeepers who played in the FIFA World cup 2014 using this equation. The subjects was 32 goalkeepers who capped more than two matches in the 2014 FIFA World Cup. The data was gathered through match analysis. In conclusion, the goalkeeper who contributed most to decrease conceded goals in the 2014 World Cup was Keylor Navas (Costa Rica). He was able to decrease his teams conceded goals by more than 5 through shot stopping. His stop rate is a third compared to the average of other top-level goal keepers. There was also a positive correlation between the traditional evaluation method (Save Percentage) and the new evaluation method (Stop Rate). Although Guillermo Ochoa and Claudio Brave where positioned below 8th with the traditional method they ranked 2nd and 3rd with Stop Rate evaluation. Therefore, it is plausible to conclude Save Percentage does not provide legitimate evaluation.

We are now developing a sports prosthesis for long jump that is optimized by the motion simulation. In the motion simulation, however, it is difficult to fully evaluate material strength of the proposed prosthesis. The purpose of this study is to investigate material strength property of the prosthesis using both of a finite element model and trial products. The first actual trial product of the prosthesis was based on the shape of the existing sports prosthesis, and the prosthesis was made of 81 pre-preg sheets for carbon fiber reinforced plastics (CFRP). The results showed the finite element model could endure the reaction force of the jump, although the actual trail product could not. The reason for this is that the amount of resin contained in the CFRP is small. The second trial prosthesis was made of the CFRP containing the resin more. The shape of the prosthesis was optimized by the motion simulation. The prosthesis was made of 40 pre-preg sheets for CFRP. The results of compression test showed the second trial product could not endure the reaction force of the jump. The reason for this is that the rigidity of the entire the prosthesis is low.

Sports prosthesis for lower extremity amputees has a mechanical structure similar to flat springs, and its elastic energy is expected to improve sports performance. In this study, we focus on a long jump event for track and field, in particular, on the takeoff action. The purpose of this study is to construct a computer simulation system that derives a comprehensive optimum solution for both the mechanical design parameters of the prosthesis and takeoff action to improve the performance of amputee long jump. A dynamics of human body was composed by a 10-rigid-links model to fit the target athlete. A mechanical relationship between deflection and force of the prosthesis was modeled as the flat spring theory. Parameters for the prosthesis and motion control were optimized by genetic algorithms to improve jumping distance. The takeoff action with 6 m jumping distance was reproduced after the optimization. Simulation results showed the prosthesis shape and takeoff action were related to the ground reaction force.

Recently, number of patients developing knee arthropathy is on the rise due to increasing number of elderly people in Japanese aging society. Knee osteoarthritis (OA) is an arthropathy developed by initial wear of knee cartilage followed by deformation of lower limb skeleton causing inflammation in a knee joint. Increased pain felt in the knee due to the OA progression can hamper with motions in daily life leading to eventual development of lifestyle related diseases such as osteoporosis. As a conservative treatment, knee braces are used and conventional braces have the two main functions of protecting the knee from external forces and stabilizing the joint.

In this research, knee braces with load reduction effect were developed. The braces have completely new mechanism that applies traction force on the knee joint to reduce the load on the medial compartment of the joint by having linkage added to the joint component on the medial side of the brace. The aim of this research was to investigate the ability of the braces to reduce the medial compartment load.

Since the anterior cruciate ligament(ACL) rupture is a serious sports injury, it is important to clarify the injury mechanism to establish a preventive method. Although the knee joint valgus torque and knee joint anterior shear forces in sidestep-cutting maneuvers are one of the main risk factors of ACL injury, it is not clear how this torque and force is generated and what role it plays in cutting maneuvers. Therefore, the purposes of this study were to quantify the dynamic contribution of the joint torques to the knee joint valgus torque, the knee joint force, and ground reaction forces(GRF) generated during sidestep-cutting maneuvers based on multi-body dynamics. Three-dimensional movement analysis was carried out to investigate one male participant performing anticipated 90° sidestep-cutting maneuvers. Trajectories of 47 marker on the body and GRF of the support leg were measured with VICON-MX system and a force plate, respectively. Knee joint valgus torque and-, knee joint anterior/posterior force, were calculated during the first 50 ms of the contact phase. The results indicate that 1) internal rotation of the hip joint torque mainly contributed positively to the knee joint valgus torque, and it did not contribute to the ground reaction force, and 2) extension of the knee joint torque mainly contributed positively to the knee joint anterior shear forces, and it contributed negatively to the ground reaction force in the invasion direction.