Yoshiki Muramatsu

Improvement and quantitative performance estimation of the back support muscle suit

We have been developing the wearable muscle suit for direct and physical motion supports. The use of the McKibben artificial muscle has opened the way to the introduction of “muscle suits” compact, lightweight, reliable, wearable “assist-bots” enabling manual worker to lift and carry weights. Since back pain is the most serious problem for manual worker, improvement of the back support muscle suit under the feasibility study and quantitative estimation are shown in this paper. The structure of the upper body frame, the method to attach to the body, and the axes addition were explained as for the improvement. In the experiments, we investigated quantitative performance results and efficiency of the back support muscle suit in terms of vertical lifting of heavy weights by employing integral electromyography (IEMG). The results indicated that the values of IEMG were reduced by about 40% by using the muscle suit.

Quantitative performance analysis of muscle suit — Estimation by Oxyhemoglobin and deoxyhemoglobin

Exoskeleton systems have been largely developed though, quantitative performance estimation has not been reported so far. We have been developing the wearable muscle suit for direct and physical motion supports. The use of the McKibben artificial muscle has opened the way to the introduction of “muscle suits” — compact, lightweight, reliable, wearable “assist-bots” enabling manual worker to lift and carry weights. By applying integral electromyography (IEMG), we show quantitative performance results and efficiency of the muscle suit in terms of keeping posture and lifting. However index for quantitative estimation is only IEMG. In this paper, we then introduce Oxyhemoglobin and deoxyhemoglobin which express the form whether hemoglobin has oxygen or not. Since muscle uses the oxygen a lot, by observing the change in the amount of Oxyhemoglobin and deoxyhemoglobin, we assume it is possible to recognize the condition of muscle use. As a result, we find that the differences of value between Oxy and Doxy after using muscle may be likened to declare fatigue of muscle.

Estimating the Effect of Dynamic Variable Resistance in Strength Training

Strength training is important for elderly to maintain their physical ability for independent walking. Meanwhile, the risks of high-intensity strength training for elderly should be considered: blood pressure elevation and arteriosclerosis. To tackle these problems, a multi-functional training machine which offers four kinds of training motions for lower limbs and controls training load dynamically have been developed. In this study, to estimate the effects of variable training load, measurements of muscle strength, blood pressure, and muscle fatigue are conducted in strength training experiments under various load conditions. The results indicate that the dynamic load conditions have potential to inhibit blood pressure elevation and muscle fatigue with increasing muscle strength comparing to constant load condition.