The purpose of the present study was to investigate the development and recovery of muscle fatigue in the upper trapezius muscle by analyzing electromyographic signals. Six male subjects performed a simulated typewriting task for four 25-min sessions. During fatigue and the following rest periods, subjective fatigue and surface electromyography (EMG) from the trapezius muscle during isometric contraction at 30% maximum voluntary contraction (MVC) were periodically measured in the interval. We detected a significant decrease in muscle fiber conduction velocity (MFCV) (P = 0.008) and median frequency (MDF) (P = 0.026) as well as an increase in root mean square (RMS) (P = 0.039) and subjective fatigue (P = 0.0004) during the fatigue period. During the recovery period, subjective fatigue decreased drastically and significantly (P = 0.0004), however, the EMG parameters did not recover completely. Thus, physiological muscle fatigue in the trapezius developed in accordance with subjective muscle fatigue during typewriting. On the other hand, differences between the physiological and subjective parameters were found during recovery. Further studies should be necessary to reveal the discrepancy could be a major factor of a transition from temporal phenomena to serious chronic muscle fatigue and to identify the necessity of some guidelines to prevent VDT work-related chronic muscle fatigue in the trapezius.
This paper argues for the immediate use of Kansei engineering to help deal with the chaotic situation of poorly implemented and disconnected technologies. A theoretical criticism of the current industrial capitalism, together with the promotion of a new post-industrial form of capitalism, lays the foundation for an explanation of how this transition can be achieved through a proper understanding of Kansei. A detailed explanation of the interactive production system apparel demonstrates the benefits to both manufacturers and consumers. The paper concludes that the application to apparel is just one of the many potential applications to improving the lifestyle and enjoyment of individuals in the entire society.
We studied a wearable blood pressure sensor using a fiber Bragg grating (FBG) sensor, which is a highly accurate strain sensor. This sensor is installed at the pulsation point of the human body to measure the pulse wave signal. A calibration curve is built that calculates the blood pressure by multivariate analysis using the pulse wave signal and a reference blood pressure measurement. However, if the measurement height of the FBG sensor is different from the reference measurement height, an error is included in the reference blood pressure. We verified the accuracy of the blood pressure calculation with respect to the measurement height difference and the posture of the subject. As the difference between the measurement height of the FBG sensor and the reference blood pressure measurement increased, the accuracy of the blood pressure calculation decreased. When the measurement height was identical and only posture was changed, good accuracy was achieved. In addition, when calibration curves were built using data measured in multiple postures, the blood pressure of each posture could be calculated from a single calibration curve. This will allow miniaturization of the necessary electronics of the sensor system, which is important for a wearable sensor.
: Free shearing deformation of woven fabrics under uniaxial tensile load was analyzed, Equations to calculate the strains along the yarn directions and crossing angle of yarns from the cloth strains were derived.
The purpose of this study is to investigate how the different heel heights of women's shoes influence walking according to walking analysis findings. Identifying heel heights that do not impair walking comfort were also investigated. Ten female university students were chosen as subjects and asked to wear sample pumps with heel heights of 1.5, 3.5, 5.5, and 8.5 cm. The walking experiments focused on walking movements, muscular activities of the lower limbs, and ground reaction at the point of impact. A questionnaire was then used to determine comfort levels while walking. The analysis discovered that the height of the heel was positively correlated with vertical movement, and that the subsequent change in walking movements resulted in an increase in muscular activities and ground reaction, and a corresponding increase walking discomfort. It was also found that poor ratings were given for each measurement item when a heel height of 8.5 cm was used, leading us to conclude that comfort during walking is compromised when the heel height increases beyond 6 cm.
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