[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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The medial ankle sprains require a longer recovery time than that of a lateral ankle sprain. However, few studies have focused on the medial ankle sprains because of the low incidence. Therefore, a detailed injury mechanism is poorly understood. The purpose of this study was to clarify the foot and ankle bones movement when standing with ankle valgus. Thirteen males took part in this study. We scanned positional MRI in standing position. To scan MRI with ankle valgus, we had participants stood on three types of planes; flat plane, 10-degrees inclined plane, and 20 degrees inclined plane. We measured the vertical and medial foot arch bones position and hindfoot alignment view (HAV). One-way ANOVA with Bonferroni post-hoc was used to analyze the main effects of the plane angle. The main effect of the plane angle was observed for the medial navicular position (MNP), medial talus position (MTP), and HAV. Furthermore, the post-hoc test revealed that MNP, MTP, and HAV on 10-degrees plane and those on 20-degrees plane were larger than those on a flat plate. On the other hand, there were no differences between 10-degrees inclined plane and 20-degrees inclined plane in MNP, MTP, and HAV. Our results suggested that 20-degrees inclined plane restricted hindfoot valgus movement and medial movement of the navicular and talus.

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In the design and evaluation of upper limb prosthetic terminal device, the number of grasping forms of the robot hand has been diverted. This has misguided on designing and evaluating the terminal device which should suppress compensatory movements of the residual limb and body. The objective of this research was to extract features from the relation between grasp and posture control of terminal device to improve the design and selection of the prosthetic components. In this research, daily hand activities were recorded with body mounted video camera on three subjects. Grasping Direction indicating the positional relationship between trunk, forearms and hand, and the contribution ratio to grasps applied in daily life were derived. A combination of hook-shaped terminal device with radial/ulnar flexion wrist unit corresponded to 95.9% of the Grasping Direction utilized in desk work. In addition, commercially available prosthetic wrist components were modeled, and the executable desk work were evaluated. The combination of 2-Grasping Direction terminal device and the pronation/supination unit corresponded to 80.1% of the Grasping Directions. These results indicate that the proposed method is effective for the design and evaluation of the upper limb prosthesis.

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The purpose of this study was to clarify the characteristics of toe trajectory when stepping over an obstacle in the dark and the effect of light information．In this study, time series data of toe trajectory of leading foot in sagittal plane (antero-posterior direction and vertical direction) were measured from eight young adults while they stepped over an obstacle under two illuminations (Blight and Dark) and three light information by phosphorescence (with the phosphorescence materials applied to the overall and partial and without the phosphorescence materials) conditions．Principal component analysis has been applied on the 240 x 202 input matrix constructed from participant’s time-normalized toe trajectory data． Two-way (illumination conditions by obstacles) multivariate analysis of variance on the principal component scores of extracted principal component vectors (PCV) revealed the effect of significant illumination condition on PCV1(p<0.05), 3(p<0.001) and 6(p<0.05)．There were no effects of light information by phosphorescence and the interaction of illumination and light information．Reconstructed toe trajectory from PCVs indicate that participants tend to take off their toe father away from the obstacle, land their heel closer to the obstacle, and lift their toe higher in the dark condition．We further analyzed these discrete parameters statistically, and found significant differences between blight and dark conditions．Also, we analyzed take off distance, heel contact distance and toe clearance．These results were similar to those of the PCA．In conclusion, the characteristics of toe trajectories when stepping over an obstacle were different in dark and light conditions, and no effect of light information on toe trajectories was found in dark conditions．

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We examined the influences of change in muscle thickness on the muscle fiber contraction dynamics of biceps femoris long head (BFlh) during the late swing phase of high-speed running. Ten male soccer players participated and performed several running trials with their maximal efforts. A musculoskeletal model of the right leg was used to estimate the muscle fiber contraction dynamics such as muscle fiber length, contraction velocity, generation force, and pennation angle. Muscles of the lower limb except BFlh were modeled as a conventional Hill-type muscle model. BFlh was modeled as an applied Hill-type muscle model including several muscle fibers. The model of BFlh was set at two conditions; specifically, the change in muscle thickness with a constant longitudinal cross-sectional area was considered in one model, and constant muscle thickness was considered in another model. In the results, the muscle thickness decreased during the late swing phase of running. The decrease of muscle thickness was a factor for the decrease of the muscle fiber length and pennation angle. Also, the decrease of muscle fiber length affected the normalized force in the muscle fiber force-length relationship. However, the tendency of the variation in muscle fiber generation force between the two conditions in the muscle model was not consistent.

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Namba walking style, known as a movement that reduces rotational movement around the pelvic cross-section, was used in ancient Japan. This study of five participants was conducted to investigate differences between normal walking and Namba walking and to use a musculoskeletal model to analyze normal walking and Namba walking. Moreover, a three-dimensional motion analysis system and force plates were used to assess normal and Namba walking. Measured data were analyzed using musculoskeletal model analysis software (OpenSim) procedures: scaling, inverse kinematics, inverse dynamics, and static optimization. Results indicated that four muscle forces related to the upper leg were decreased, whereas two muscle forces related to the lower leg were increased.

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