Toshiya Tsurusaki

Effect of Ankle Disk Training Combined with Tactile Stimulation to the Leg and Foot on Functional Instability of the Ankle

Twenty-two university students with unilateral functional instability of the ankle participated in this study. They were randomly assigned to one of two experimental groups. Subjects in both groups were trained to stand on the affected limb on an ankle disk. In group 1, two pieces of 1-cm wide nonelastic adhesive tape were applied to the skin around the lateral malleolus from the distal third of the lower leg to the sole of the foot before the training sessions. Subjects in group 2 participated in the training sessions without the application of the adhesive tape. Training was performed for 10 minutes a day, five times per week, for a period of 10 weeks. Subjects were tested for postural sway while standing on the affected limb before, during, and after the training period. In group 1, postural sway values decreased significantly after 4 weeks compared with the pretraining performance, and they were within the normal range after not more than 6 weeks of training. In group 2, the values did not improve significantly compared with the pretraining performance until after 6 weeks of training, and they were not within the normal range until after 8 weeks of training. The findings suggest that the 2-week earlier correction of postural sway in group 1 was due to an increased afferent input from skin receptors that were stimulated by the traction of the adhesive tape.

Effective parameters derived from multiresolution analysis of surface electromyograms

Purpose of this study is to extract effective parameters for explaining muscle state based on multiresolution analysis of surface electromyograms (EMGs). The EMGs were decomposed into five levels using the Daubechies orthogonal wavelet of order 5 (db5). Two kinds of surface EMG were recorded from biceps brachii in five healthy males during muscle fatigue test and increasing load test. Selected parameters for analyzing EMGs were as follows; 1) PD(j): power of the details at level j ; 2) TPw: total power of the details concerning all levels; 3) RPD(j): power ratio of the PD(j) to TPw at level j. On muscle fatigue test, RPD(1), RPD(2), RPD(3) decreased after the test and RPD(4), RPD(5) increased contrarily. On increasing load test, RPD(3) showed a curve with two peaks at 25% MVC 30% MVC and at 45% MVC. On the contrary, RPD(4) showed inversed curve of the RPD(3) . This suggests activity of recruited fast muscle fibers.

Effect of W-sitting on Standing Posture of Preschool Age Children

[Purpose] The effect on the standing posture of healthy infants w-sitting on a daily basis was investigated in this study. [Subjects] The guardians of 39 healthy infants aged 3–6 year were interviewed about their sitting posture. [Methods] The angle formed by the horizontal line and the line connecting the two points of the iliac spine and the anterior superior iliac spine was measured as the pelvic tilt angle. Hip rotation was classified into five groups using posture analysis. [Results] In children exhibiting w-sitting, an association was found between pelvic forward tilt and hip internal rotation. [Conclusion] With daily w-sitting, a standing posture exhibiting hip internal rotation with forward pelvis tilt is easily adopted even by children showing routine development. This may increase the risk of orthopedic disease, damage to the anterior cruciate ligament, or back pain in the growth process.

Detection of Fast Fiber Recruitment by Multiresolution Analysis of Surface Electromyograms

This paper suggests possibility for detecting recruitment of fast muscle fiber on increasing load tests by multiresolution analysis of surface electromyograms (sEMGs). Recruitment of the muscle fiber can be guessed from a graph of power ratio vs. % maximum voluntary contraction concerning the detail at each level, RPD(j). RPD(j)s are extracted parameters from multiresolution analysis of sEMGs. The sEMGs were recorded from the biceps brachii in five healthy males