Quantification of Muscle Fatigue Using Surface Electromyography for Isometric Handgrip Task

We proposed a method to quantitatively estimate the degree of muscle fatigue by constructing a fatigue index, which represents the relationship between the force loss and handgrip work. This fatigue model allows the estimation of force loss non-intrusively using SEMG signal. Eight male subjects volunteered in this study to perform a series of isometric handgrip tasks at three different contraction levels. Handgrip work was estimated from SEMG signal, which was then used as the independent parameter for the fatigue index to estimate the force loss. The evaluation was performed by comparing the force loss that was estimated using the proposed fatigue index and the one measured from dynamometer. The average error of the estimated muscle fatigue using the proposed method was less than 10% MVC

Compact Design of Work Cell with Robot Arm and Positioning Table under a Task Completion Time Constraint

Abstract-A work cell is generally designed to achieve a high throughput and its size is typically viewed as contingent to component sizes. In this paper, we aim to design a compact work cell (spatial requirement) and to minimize its task completion time (temporal requirement) to a value set as a constraint. By doing so, a work cell occupies a minimal space and achieves its desired throughput. The work cell size is evaluated based on the size and the swept volume of components. This evaluation is important since a robot arm can have a very large swept volume depending on a given task. To satisfy the spatial and temporal requirements, we propose the integration of the base placement optimization, goal rearrangement, and motion coordination between the robot arm and the positioning table. Furthermore, we introduce two motion coordination schemes based on the spatial and temporal requirements. We showed the effectiveness of the proposed method through simulations

Prevalence of the metabolic syndrome in elderly and middle-aged Japanese

AbstractBackground/PurposeDiagnosis and management of the metabolic syndrome (MetS) are beneficial for successful aging. In spite of several criteria for MetS, there is little information on cardiometabolic risk clustering in elderly Japanese. The purpose of this study was, therefore, to determine the relationship between age-associated changes in obesity and metabolic components in the Japanese.MethodsWe analyzed data from the nationwide survey conducted in 2000. Using Adult Treatment Panel III (ATP III) and Japanese diagnostic criteria for MetS, we analyzed 2366 people aged from 40 to 79 years (men, 1425 and women, 941) from the total participants.ResultsThe prevalence of MetS was almost three fold higher by modified ATP III, International Diabetes Federation, and Japanese criteria, in elderly women than in middle-aged women, whereas no difference was found between middle-aged and elderly men by the three criteria. A marked increase in the prevalence of MetS was found by modified ATP III and International Diabetes Federation criteria compared with that by the Japanese criteria in women. Among the risk factors, the prevalence of central obesity and dyslipidemia increased only in women and that of high fasting glucose and high blood pressure increased in both genders with aging. Among the MetS subjects who fulfilled the modified ATP III criteria, more clustering of risk was observed in elderly than in middle-aged subjects, especially in women. Blood pressure increased and triglyceride decreased in both genders, and non-high-density-lipoprotein cholesterol decreased in elderly men. The prevalence of dyslipidemia decreased in elderly men.ConclusionAging is an important factor that affects the metabolic abnormality, and aging of the population would lead to increase in the prevalence of MetS. Therefore, the development of better approaches to the prevention and management of MetS is necessary for successful aging in our society