[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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A mathematical algorithm was proposed for the elimination of the gravitational effect on accelerometer data. We evaluated the reliability of the corrected linear accelerations. Five healthy students were instructed to walk with a greater medio-lateral trunk sway. The effect of gravity was calculated from the raw angular signals, and the accelerations were measured using a triaxial gyro-accelerometer combo sensor mounted on the sternum of the subjects. The raw acceleration signals were transformed to a spatial coordinate system by a mathematical algorithm on the basis of the sensor’s orientation. In addition, positional data of the accelerometer were obtained using a three-dimensional motion analysis system in order to calculate linear acceleration. The reliability under each condition (raw or corrected, 3 directions) was assessed using waveform similarity or the intraclass correlation coefficient (ICC). The results revealed that the accelerations were influenced by gravity, and a significant increase in reliability was observed in the corrected anterior-posterior and mediolateral directions of sway. The proposed method was found to be reliable and it can be potentially adopted for quantitative gait analysis.

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The purpose of this study was to investigate effects of the trunk inclination on mechanical energetics of gait in healthy males. Ten healthy males were asked to walk in three different trunk inclinations : (1)normal for the subjects, (2)with trunk leaning 10°forward and (3)with leaning 10°backward. The gait motion was captured with a Vicon612 system and the ground reaction forces during the support phase were recorded with two Kistler force platforms. In the forward lean gait, the positive work at the hip increased and that of the knee and ankle decreased, compared with the normal gait. The total mechanical work of three leg joints and effectiveness index of mechanical energy utilization (EI) in the forward lean gait were similar to these of the normal gait. In the backward lean gait, the total mechanical work was greater and EI was smaller than the normal gait. These results indicate that the forward lean gait is unlikely to affect the EI of gait, and that the backward lean of the trunk in gait seems to decrease the EI because of greater mechanical work done by the leg joints.

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