In this article a topic of digitally archiving intangible cultural heritages which include dance, performing arts as well as cultural event such as festivals. These intangible cultural heritage includes human body motions. As for measuring human body motions, a system called motion capture system has been currently used. Although it is a powerful tool to get precise data about human body motion, it is not necessarily ideal for obtaining data for traditional dance and performing arts. Advantages and disadvantages of these systems have been discussed. Some of the information processing techniques including an analysis of Japanese dance movement and similarity-based retrieval method for body motion data. Lastly, a topic of reproducing a very large cultural event, Gion Festival Float Parade, with virtual reality technology, which currently being developed in the author’s laboratory is presented.

Knowledge of joint kinematics in the lower limb is important for understanding joint injuries and diseases, and evaluating treatment options and outcomes. However, limited information is available about the kinematics of the lower limb joints in high flexion during floor sitting activities. In this study, we used an electromagnetic motion-tracking system to measure the hip and knee joint kinematics of ten healthy male and ten healthy female subjects sitting into and standing out of the following positions: kneeling on knees, sitting cross-legged, kneeling with legs to the side, sitting with legs outstretched, and deep squatting. We also measured the hip and knee kinematics when donning and removing a sock while standing or sitting on the floor, since they require the same high joint flexion required for floor sitting activities. First, the data were used to produce joint angulation patterns against the normalized time for each individual performing each activity. We proposed a way to split the kinematic curves into 3 to 5 phases in order to preserve the typical features of the original curve, even after statistically averaging all the curves. Next, the maximum hip and knee joint angles during each motion were identified directly from the original curves. Furthermore, the relationship between the hip and knee joint excursions was investigated. The results indicated that in most activities, the maximum joint angles did not occur during when resting on the floor but during the sitting or standing phase. Among all the activities, donning and removing a sock while standing required the maximum hip flexion angle of 157.5±20.4°, and the motion starting with one foot forward to sit into or to stand out of the kneeling required the maximum flexion angle on the forward knee of 157.1±10.0° respectively. In most of the motions investigated, a strong relationship was found between the hip and knee joint motions, indicating the bi-articular muscles’ co-contraction during the sit to stand activities.

Two experimental studies were conducted on control of the facial muscles for French horn playing. The first study investigated activity of the embouchure-related muscles during pre- and post-attack phases of sound production by trained French-horn players. No difference in EMGs and facial kinematics between the two phases was found, indicating importance of appropriate formation of pre-attack embouchure. EMGs in all muscles increased with an increase in pitch, and they also increased with tone intensity without interacting with the pitch effect. Additionally, facial skin movement remained constant across all pitches and intensities. Therefore, the contraction of the facial muscles is fundamentally isometric by which tension on the lips and the cheeks is regulated for flexible sound parameter control. The second study investigated the difference of facial muscle activity between advanced and amateur players. When performing a simple long tone at varied levels of pitch, no group difference in the activity was revealed. However, when performing an octave pitch modulation, the upper lip controlling muscles differed between the two groups. These muscles play an important role in complex pitch control, which requires long term specific training.

A 3-D force transducer was installed at the neck of a violin. To investigate the characteristics of the fingerboard force while expert and novice players of the violin produced two tasks: two short monotones repeatedly, and a long tone vibrato. Surface electromyography was also recorded from the left hand, an arm, and muscles. At slow tempi, the fingerboard forces were characterized by an initial pulse-like force, followed by a leveled force during the finger contact period. At tempi higher than 2 Hz, only pulsed profiles were observed. The peak force exceeded 4.5 N at 1 and 2 Hz, which decreased at higher tempi. The forearm and hand muscular activity was increased with tempo, on the other hand. There was relatively large variability between players in fingerboard force. Novice players had a lower level of fingerboard forces across all tempi and all fingers used compared to experts. The fingerboard force during vibrato was characterized by a steady level of vertical force, and vigorous tangential shaking force. The present study verified the feasibility of measuring the fingerboard force during an actual violin performance, and the tempo-, vibrato-, finger-, and skill-level dependent, and modulation of the fingerboard force and muscular activity were discussed.

The swallowing feeling is an important factor in the enjoyment of eating and drinking. Many studies have investigated the swallowing feeling using subjective assessments; however, few studies have taken an engineering oriented approach to the swallowing feeling. Therefore, our research goal was to model the swallowing motion and feeling using swallowing sounds. In this paper, we used carbonated water with three different stimulation intensities as swallowing samples, and measured the swallowing sounds and EMG signals during drinking the samples. Then, we used the following three indices to quantify the swallowing feeling; area and duration of high power segment of the recorded swallowing sounds and the active duration of the EMG signals. As a result of the analysis, statistically significant differences between the samples in each index were confirmed. The result of each index indicated the same response to the stimulus intensity of the carbonated water samples. The weak stimuli, which seemed to create pleasant sensation, increased the swallowing duration, whereas the strong stimuli, which we seemed to create unpleasant sensation, decreased the swallowing duration. Therefore, we considered that humans unconsciously decided how to swallow samples based on stimulation intensity to obtain the best swallowing feeling, which had the characteristics of the convex upward to the stimulation intensity.

All goal-directed tasks are redundant at some level of analysis, to the extent that an infinite number of equivalent solutions exist for achieving the task goal. A solution manifold is composed by the combinations of execution variables that lead to a perfect task result. In previous studies of skilled task performance, variability in the execution variables was aligned with the solution manifold. This suggests the central nervous system determines the motor commands in the execution space where variability has the least detrimental effect on the result (task). These previous studies focused on the data set distributions in execution space, whereas recent studies have developed new analyses for the temporal structures. After reviewing these two analyses in detail, I examined their characteristics by applying these analyses to the experimental data set of a bimanual pinch-force generation task. The results demonstrated the two analyses could produce different conclusions for performance according to the task duration.

The aim of this study was to demonstrate the differences of the release parameters (position, velocity, and angle of dart at the moment of release) between the experts and novices in dart throwing. We focused on the variability of the release parameters and the amount of compensatory coordination between the release parameters. The movements of the dart and index finger were captured using seven 480 Hz cameras. The smoothed data were made upsampling process to 1000 Hz, using cubic spline function. The amount of compensatory coordination was quantified using “Index of Coordination for Release Parameters (ICRP)” (Kudo et al. 2000) The SD of the vertical position on the board for the experts was significantly smaller than for the novices, suggesting that the long term practice have made the performance superior. The SDs of all release parameters for the experts were significantly smaller than for the novices. ICRP for some experts was significantly greater than for the novices, indicating utilization of the compensatory coordination. Other experts exhibited less variability in the release angle, which influenced the outcome the most, instead of utilizing the compensation coordination for the accurate throws.

In the present study, we defined the ability of motor control based on the somatosensory input as a somatosensory-motor integration function, and performed a motor task termed as the kinetic-equilibrating task to evaluate this function. The kinetic-equilibrating task was performed by using a haptic device. The subjects were instructed to maintain their limb position against the passive force, and the change in the limb position was recorded. The recorded values were compared in the ascending and descending phase of the passive force. In addition, the influence of the duration of the subjects’ sports career on the recorded values was examined. The results indicated that maintain the limb position was more difficult than in the ascending phase of the passive force, and a marked influence of the duration of the subjects’ sports career was showed in the descending phase. Moreover, by using a kinetic-equilibrating task, we verified the practice effect on the somatosensory-motor integration function, motor function (fluctuation of force production), and sensory function (detection threshold of movement). Furthermore, the values recorded during the kinetic equilibrating task in the ascending and descending phases had both improved after the practice period. In addition, the motor function and sensory function had also improved after the practice period. Thus, the current findings confirmed the validity of using the kinetic-equilibrating task, involving a haptic device, for the evaluation of somatosensory-motor integration function. These results suggested that the task was a very useful practice method for improving somatosensory-motor integration function, motor function, and sensory function.

For individuals with severely compromised motor functions, personal computers are indispensable tools that help ensure vital communications and promote social participation. Their machines come equipped with special pointing devices that use orthogonal scanning software and have a simple on/off switch. But, this necessitates us to first determine several operational parameters on a trial/error basis. Therefore, we proposed a parameter determination method using the measured response time of individual users. Subsequently, we attempted to validate the efficacy of the parameter determination through experiments using both healthy volunteers and those with motor disabilities. Consequently, the optimum values were verified to be effective for decreasing operation times without increasing their total number on average.

The Japanese Standards Association (2000) and the International Organization for Standardization (2011) have standardized tactile bars (bar-shaped symbol on a stop key) and dots (dot-shaped symbol on a start key) that enable people with visual impairment to discriminate the keys on consumer products. However, to the best of our knowledge, there have been no studies regarding their recommended sizes and shapes in view of the establishment and modification of standards related to tactile bars and dots. The purpose of this study is to evaluate the influence of the sizes of tactile dots and bars on their discriminability to determine the appropriate size of tactile bars (as distinguished from tactile dots) regardless of the aging and tactile experiences, which markedly affect tactile acuity on the fingertips. Younger and older participants with or without visual impairment tactually discriminated tactile dots and bars presented individually, in random order, via a two-alternative forced-choice task. The results showed that participants discriminated tactile bars from tactile dots faster and more accurately as the dimensional difference between the bar length and width increased. In particular, younger sighted, younger, and older blind participants distinguished tactile bars of more than +2.0 [mm] length from tactile dots correctly. However, the older sighted participants required a bar length of +3.0 [mm] for accurate discrimination of tactile bars. In addition, younger and older sighted persons discriminated tactile bars with a length of +4.0 [mm] in less time, whereas younger and older blind participants were able to discriminate tactile bars of more than +3.0 [mm] length. On the other hand, tactile dots with a larger edge radius of curvature have higher discriminability than tactile dots with a smaller edge radius of curvature for dots of identical height.

Touch-sensitive screens that serve as displays and input devices have been adopted in many portable terminals such as smartphones and personal media players, and this market has expanded greatly. A feature of touch-sensitive screens is that their graphical user interface (GUI) can be designed arbitrarily. However, it has been pointed out that GUIs may be difficult to use if the designer is unfamiliar with human operational characteristics. This is because there is insufficient knowledge about the operational characteristics of humans. Therefore, in this study, we aimed to evaluate the characteristics of pointing when using portable terminals with touch-sensitive screens, and we conducted an experiment to obtain knowledge that can be used in the design of easy-to-use GUIs. In this experiment, we evaluated the characteristics of pointing by measuring the distributions of the pointing positions and pointing time. The subjects who participated in the experiment were asked to operate a portable terminal with a touch-sensitive screen under three operational conditions. The results showed that the pointing position distribution depended on the target display area in all operational conditions. We also found that the pointing time was better in the areas that the thumb could reach without extension or flexing during one-handed operations. Furthermore, we describe an effective approach for designing an ellipsoid touch-sensitive area based on the pointing position distribution determined in this experiment. We also evaluated the effectiveness of this new design approach.

Tactile raised characters are useful in creating accessible designs for the benefit of people with acquired visual impairment. For instance, tactile raised characters are used on elevator buttons and television remote controls as an assistive tool based on the philosophy of accessible design. However, sufficient reliable data on the appropriate size for perception of such characters are not available. In this study, we investigated the influence of the size of tactile raised Arabic number characters (0 through 9) on their perceptibility using two experimental designs. One experiment involved young and old individuals with normal vision who were unfamiliar with the systems intended for people with acquired visual impairment, the other experiment was for young and old visually impaired persons. The tactile raised characters were presented one by one in random order using our developed experimental apparatus. There was a correlation between the size of the tactile raised characters and their perceptibility. This knowledge will be useful in discussing revisions to the Japanese Industrial Standard regarding tactile raised characters or in formulating new guidelines pertaining to tactile substitution tools.

Taekwondo is an Olympic event characterized by a diverse array of kicking techniques. To win a competition, it is necessary to kick the opponent and score more points than the opponent. Previous studies have shown that a greater number of roundhouse kicks (RHK) than other types of kicks are delivered in Taekwondo competitions. The aim of this study is to analyze the kinematical characteristics of the lower torso and kicking leg in Taekwondo RHK. We captured body segments using a Vicon MX+ system (250 Hz). The results are summarized as follows: 1) In event of impact (IMP), the contribution of knee joint extension was about 60% of kicking speed. 2) In IMP, the contribution of knee joint extension was mainly produced by an angular velocity of extension knee joint. 3) Increasing extension angular velocity of knee joint was affected by patterns of left-rotation angular velocity of lower torso and flexion angular velocity of hip joint. In conclusion, to kick at a faster speed and in a short time, it is critical to have a greater extension angular velocity of knee joint with effective patterns of both left-rotation angular velocity of lower torso and flexion angular velocity of hip joint.

In general, it is most effective to use a combination of various speeds and spin characteristics in order to maintain the service game in tennis. Thus, the authors investigated the relationship between the spin characteristic of the ball and the kinematics of the upper body in a previous study. The swing direction was found to be not mainly controlled by arm-swing motion but the change in upper-body posture. It is assumed that the kinematics of the upper body are mainly controlled by lower-limb and trunk kinetics. The purpose of this current study is to investigate the relationship between trunk posture and the kinetics of the lower limbs and trunk. Our findings (for a right-hand player) are as follows. The mechanical energy of the body is mainly generated by the extension torque of both knee joints. The energy flows mainly from the left leg into the lower trunk by joint force power. The right hip joint torque acts to resist the moment that acts on the trunk with mechanical energy flow. Thus, the main role of the left leg is to generate mechanical energy to obtain head speed. Conversely, the role of the right leg is not only to generate mechanical energy but also to control the trunk posture to change the spin characteristics of the ball.

The purpose of this study was to compare the variability muscular activities and movement smoothness of the upper limbs during the speed-increase phase of a basketball-bouncing task between experienced basketball players and novices. Participants were nine college basketball players and six novices. The participants were instructed to synchronize their bouncing movements with an auditory signal (100 bpm), and bouncing the ball as fast as possible when a light-emitting diode signal was turned on. During the bouncing task, two-dimensional body kinematics was recorded using a high-speed camera at 100 frames/s and the number of angular jerk (derivative of acceleration) zero-crossings was calculated. The variability of muscular activities was acquired by surface electromyography signals obtained at the shoulder, elbow, and wrist muscles. A muscle co-contraction index (CI) was calculated on the based on the activities of the flexor and extensor muscles of each joint.

The experienced basketball players showed a smaller CI and a smaller number of the angular jerk zero-crossings in the wrist muscles than the novices. These results indicate that the experienced basketball players bounced the ball more smoothly with lower joint stiffness than the novices. In contrast, the novices have “jerky” movements and higher co-contraction than the experienced basketball players in the speed-increase phase. These results suggest that experienced basketball players can control the speed of the ball with lower co-contraction and produce smoother bouncing movements in the speed-increase phase of the task than the novices.

It is possible to identify softball defence as involving the dual task of catching and judging. Moreover, it is inferred that the process of visual information acquisition affects judgement in softball defence. Twelve experienced female softball players and eleven intermediate female softball players participated in this study. We compared the defence skill scores of the single-task test and the dual-task test, and the rate of head turn for the two groups of players when judging in the process of visual information acquisition. The results of the single-task test showed that there were no significant differences in the defence skill scores between the two groups. However, the results of the dual-task test showed that the defence skill scores of the experienced players were significantly higher than those of the intermediate players. Furthermore, the head-turn rate of the experienced players was significantly smaller than that of the intermediate players in normal condition, while in visual limited condition there were no significant differences between the two groups. In conclusion, it was suggested that differences in the extent of head turn is one of the factors in differences in softball defence skills.

The high occurrence of concussions in contact sports, particularly in American football, is gained the attention of scientists as a unique opportunity to collect biomechanical data towards the characterization of Mild Traumatic Brain Injuries (Mild TBI). Concussive and non-concussive head acceleration data obtained from head impacts in football games were utilized to evaluate two injury criteria for TBI. These criteria, which we refer to as Rotational Injury Criterion (RIC₃₆) and Power Rotational Head Injury Criterion (PRHIC₃₆), were derived from the amplitude and the time duration (limited to 36 ms) of primal angular head kinematics. A well validated Finite Element (FE) model of the human brain was employed to investigate effective injury criteria for TBI. Correlation analyses were performed between the proposed criteria and FE-based brain injury predictors, namely Cumulative Strain Damage Measures (CSDM). CSDM is defined as the percent volume of the brain that exceeds a specified first principal strain threshold. The RIC₃₆ exhibited significant correlation to CSDM with strain thresholds of less than 15% (R>0.89). In addition, PRHIC₃₆ was also strongly correlated to CSDMs with strain thresholds equal to or greater than 20% (R>0.90). Further investigation with additional head motion data, including TBI cases, seems necessary to evaluate the predictive capabilities of RIC₃₆ and PRHIC₃₆.

Daily continuous measurement and analysis for lung volume are important in establishing early detection of lung diseases. Most e-textile-based wearable spirometers use torso girths to estimate lung volume, including chest girth and abdomen girth. However, if we assume to use only one calibration posture to minimize users’ burden, estimation errors will increase when users assume postures other than ones used for calibration. To resolve this issue, we analyzed movement of torso girths with motion captures at standing, sitting and forward-bending (30, 60, 90 degrees) postures; and found that liner adjustment is suitable for reducing estimation errors depending on forward-bending postures. The adjustment with coefficients optimized with a brute-force method improved the differences of estimation errors between the calibration posture and the others from 0.30±0.12 liter to 0.03±0.05 liter. The adjustment with coefficients yielded from torso-girths’ average values of each posture improved the differences to 0.23±0.09 liter.

We have developed a head care robot equipped with scrubbing fingers. This robot assists with hair washing and scalp care in hospitals or care facilities, and it eases the burden of healthcare professionals and care workers while it brings frequent hair washing and a higher Quality Of Life (QOL) to patients and others in need of nursing care. Based on the quantitative evaluation on relaxation and cleanness and qualitative evaluation, the head care robot is improved. As a result, firstly, a closed five link mechanism is developed to expand the range of motion of the end-effecter. Secondly, virtual compliance control system is implemented to realize the comfortable head care.

The musculoskeletal system of astronauts degenerates in the International Space Station (ISS) under microgravity. There are various countermeasures to prevent this degeneration, but they often require large-scale facilities. Therefore, convenient and effective training methods to prevent degeneration are strongly desired. Our group proposed an innovative method called “hybrid training” (HT) and verified the effects of the training in healthy subjects under 1 g of Earth’s gravity and simulated microgravity. The HT combines voluntary and electrically induced muscle contractions. In clinical settings, this method could increase the effectiveness of strength training programs for the elderly and improve the mobility of paralyzed limbs. With the goal of eventually using the HT in the Japanese Experiment Module (JEM) of the ISS, the system design was evaluated in relation to the following: stimulation conditions for safer use, application of a moistened silver electrode, electromagnetic compatibility (EMC) of developed stimulators and electric field emissions from the stimulated human body, a HT simulation of an astronaut floating in the JEM, and influence of HT-induced motion of an astronaut fixed in the JEM on the ISS.

Gait training is usually done by physical therapist who evaluate the abnormalities in the patient’s gait and employ such treatments as controlling patient pelvis to improve repeatability and symmetry of gait pattern. Related works that automate gait training impose constraints on hemiplegic patient’s naturalistic gait because they cannot correspond to the individual features of hemiplegic patient. To solve this problem, physical therapy’s pelvic assistance based control gait training robot was developed that can corresponds to the individual features of hemiplegic patient in our laboratory. As the first step of development of this robot, this paper describes a mechanical model that represents manual patient’s pelvic assistance provided by physical therapist. We showed experimental results of gait training measurement that was done by physical therapist for patient with hemiplegia, and revealed characteristics of manual assisted technique.

Collateral ligament shortening is a major cause of metacarpophalangeal (MP) joint extension contractures. Although we previously developed a rotational dynamic splint (hereafter, RDT-type splint) for stretched collateral ligaments, it did not exert traction on the palmar side of the MP joint. In the present study, we developed a pneumatic dynamic flexion and traction splint (hereafter, DTF-type splint) to circumvent this issue. To evaluate the improved properties of the new splint, we compared muscle reaction, finger blood flow, and Visual Analog Scale-score. Joint space was evaluated with CT images. Our results suggest that the DTF-type splint has low effect to give healthy human fingers and the whole MP joint is pulled.

Renewable energy research has been advocated to slow down climate change and maintain economic growth. Streamflow is valued as a source of energy, and an environmentally friendly, low-friction sealing system that employs biomimetic technologies is proposed for its utilization. To test this biomimetic seal, a dynamo-electric generator with waterproof ancillary systems is installed under water. This system uses lip seals over the rotating shaft which function to prevent the ingress of water. To improve the power generation efficiency with the constantly changing water flow, excellent frictional properties of the seal across varying rotational speeds is required. A sealing system was successfully developed using a hydrated material (polyvinyl formal; PVF), which mimics articular cartilage in a natural synovial joint. Polyethylene glycol (PEG) dissolved in distilled water, a non-Newtonian fluid, was used as a lubricant. These materials have low toxicity and low environmental impact should they become exposed to nature. It is shown that the biomimetic sealing system exhibits excellent frictional properties with extremely low ingress of water.