[in Japanese]

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[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

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[in Japanese]

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Magnetic pules stimulation was carried out for the peripheral nerve of the forearm of five healthy adults by using the magnetic stimulation device. Dorsiflexion movement of the wrist was measured using a digital goniometer under the following stimulus conditions. Magnetic field strength : 3 stage. Stimulation frequency 10 Hz to 50 Hz. Stimulation time : 0.5 to 2 sec. According to the stimulation conditions, wide range in bending angle of the wrist over 100 degree was observed.

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In the present study, we developed a method to quantify adaptive change in walking pattern during split-belt treadmill walking using a tri-axial accelerometer attached to the pelvis. Specifically, the acceleration signals were decomposed by Fourier analysis using stride frequency as the fundamental harmonics, and the amplitudes of the even harmonics were compared with those of the odd harmonics. If human walking is perfectly symmetrical, the acceleration patterns should be bi-phasic, resulting in comparatively larger even harmonics. To evaluate the usefulness of the present accelerometer-based method, we investigated locomotor adaptation during split-belt treadmill walking on 5 human participants. At the beginning of the adaptation process, stance period and step length were longer on the slow leg than on the fast leg. As locomotion was adapted to the different speed condition, the stance period and step length decreased on the slow leg and vice versa on the fast leg, indicating that locomotion became more symmetrical. We observed that the even harmonics of the anteroposterior acceleration signals increase over the course of adaptation, indicating that change in asymmetry in human walking was successfully quantified using the proposed method. Therefore, the present methodology may serve as a simple yet effective mean to quantitatively evaluate change in locomotor symmetry in gait rehabilitation using a sprit-belt treadmill.

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The purpose of this study was to investigate the leg discomfort related to swelling of the leg during prolonged standing and walking. Ten male subjects were asked to stand upright for 120 min and walk at 4.8 km/h for 120 min (rest: work ratio, 10:20). To evaluate swelling, the discomfort in the thigh, lower leg, and foot were assessed every 5 min, and the circumference and muscle hardness of the thigh and lower leg, impedance value of the lower leg, ground contact area of foot, and height of the first cuneiform bone were evaluated every 20 min. Leg discomfort gradually increased in both standing and walking sessions and was larger at the lower leg and foot compared to the thigh. During the standing session, subjects complained of undesirable sensations, such as lower-leg fatigue, foot strain, pain, and pressure, more frequently and sooner than they did during walking. Circumference of the thigh and lower leg increased over time in the standing position but did not change during walking. The impedance of the lower leg decreased over time during standing but gradually increased during walking. These observations suggest that the discomfort and related symptoms associated with swelling of the leg, including fatigue, strain, pain, and pressure sensations, appear to be prominently related to the lower leg posture during standing. Prolonged walking, compared to standing, appears to attenuate symptoms associated with the occurrence of leg discomfort related to leg swelling.

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Anterograde intramedullary nail, which is currently the main stream, requires cutting the rotator cuff of the supraspinous muscle, and the application of a locking plate requires a large skin incision, being invasive. To minimize the invasiveness, retrograde intramedullary nail was developed by our collaborators. In this study, to evaluate the fixation stiffness and displacement of retrograde intramedullary nail, mechanical tests were performed for comparison with the conventional anterograde intramedullary nail and locking plate. The test implants were retro- and anterograde intramedullary nails and a locking plate. Two-part fracture was prepared by applying AO classification Type A3 osteotomy to a resin-made humerus model. As mechanical tests, valgus, torsion, and compression tests were performed. The displacements induced by valgus and compression decreased in the models with the locking plate, retrograde intramedullary nail, and anterograde intramedullary nail in this order, clarifying the superior fixation stability of the anterograde intramedullary nail. When the torques of internal and external rotations was averaged, the highest torque was detected in fixation with the locking plate. Retrograde intramedullary nail was equivalent to the other internal fixations in fixation against torsion of internal rotation, and superior to the locking plate in fixation against valgus and compression, suggesting that there is no problem with the fixation stability. Retrograde intramedullary nail is useful as an internal fixation method for the treatment of proximal humeral fracture with regard to reducing invasiveness.

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