[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

In order to evaluate one's risk of tripping easily in near future, this study proposed a method to estimate the minimum toe clearance (MTC) during walking from Floor Reaction Force (FRF) of the users and a model that made from the gait data of third party, and evaluate its robustness and accuracy. First, we measured the FRF and the MTC of one gait cycle from 26 health young and 6 healthy elderly participants. Second, we build 10 different models to estimate the MTC from the FRF, by using randomly chosen 20 young participants' data. The robustness of the proposed method has evaluated with the contribution ratio and independent variables that used to build the models. Moreover, the accuracy of the proposed method has evaluated with the root mean squared error (RMSE) and coefficient of correlation between the estimated MTC and the actual MTC that derived from the remaining data of 6 young and 6 elderly participants. The contribution ratio of the models were 0.67±0.03 and 5 independent variables were commonly used to build the models. RMSE between the estimated MTC and the actual MTC were 4.6±0.7[mm] for young participants and 6.4±0.5[mm] for elderly participants, which is similar to the results of previous study, and the estimated MTC and the actual MTC show a signifi cant correlation. From these results, we confi rmed that proposed method can build robust model regardless of the participants group, and can estimate the MTC as accurate as previous study.

View full abstract

The purpose of this study was to investigate the characteristics of sprint motion in children. Therefore, the 3D sprinting movements of male children aged from 8 to 11 years old (child group: n=20) and adults in their 20s (adult group: n=10) were measured. The child group showed a particularly low step frequency index, in which the effects of leg length were eliminated. This is one of the factors determining sprint speed. This originated from the fact that, in children, their feet land at positions further from the body at initial contact, and the hip and knee joints fl ex immediately after the initial contact.

View full abstract

This paper studies on running movement. In order to prevent injuries during running, we focused on the initial peak of the ground reaction force as well as the leg stiffness, and experimentally studied if visual feedback can be used to adjust these values. In detail, the ground reaction force was measured from the subject while running on an instrumented treadmill with force sensors. The initial peak of the ground reaction force was calculated from the measured data, and the leg stiffness was estimated with a spring-mass model. Then the information was visually fed back to the subject in real time. As the result, it was clarifi ed that both the absolute value and the standard deviation of the initial peak of the ground reaction force and leg stiffness were reduced with visual feedback. These results suggest that visual feedback affect running movement, and we expect visual feedback to prevent running injuries in the future.

View full abstract