Hiroji Tsujimura

Measurement of Whole-Body Vibration in Taxi Drivers

Measurement of Whole‐Body Vibration in Taxi Drivers: Mitsuhiko Funakoshi, et al. Kyushu Institute for Social Medicine—In a previous epidemiological study we reported that the prevalence (45.8%) of low‐back pain (LBP) and the two‐year incidence (25.9%) of LBP in 284 male taxi drivers in Japan was comparable with rates reported for other occupational drivers in which LBP frequently occurs. LBP was significantly related with the level of uncomfortable road vibrations, and, importantly, increased with total mileage. The aim of this study was to measure whole‐body vibration (WBV) on the drivers seat pan of 12 taxis operating under actual working conditions. The results were evaluated according to the health guidelines in International Standard ISO 2631‐1:1997. Finally, the relation between total mileage and WBV was investigated. The majority of the frequency‐weighted r.m.s. accelerations of the taxis fell into the “potential health risks” zone, under ISO 2631‐1:1997. It was clear that the taxi drivers were exposed to serious WBV magnitudes. Therefore, occupational health and safety management should be carried out to help prevent adverse health effects in taxi drivers. In particular, reduction of WBV in taxis and shortening of driving time to reduce duration of WBV exposure should be considered. Moreover, because many taxi drivers work 18 h every other day, the shortening of working hours and taking of rest breaks while working should be considered. Frequency‐weighted r.m.s. accelerations of taxis had a tendency to decrease as total mileage increased. The relation between total mileage and WBV should be investigated by taking measurements on the floor and the back rest in addition to the seat pan.

A field study of exposure to whole-body vibration due to agricultural machines in a full-time rice farmer over one year

A field study of exposure to whole‐body vibration due to agricultural machines in a full‐time rice farmer over one year: Hiroji Tsujimura, et al. Division of Occupational and Environmental Health, Department of Social Medicine, Shiga University of Medical Science

Exposure to Whole-Body Vibration of Forklift Truck Operators in Dockyards

Low-back disorders are well documented as occupational hazards among forklift truck operators. The potential risk factors that may lead to low-back pain include exposure to whole-body vibration (WBV). In Europe, test methods were developed to evaluate WBV in industrial trucks, and the European Standard which defines the methods has been published. We measured the vibrations of forklift trucks operated in the Hanshin harbour area adopting procedures based on the CEN test and report the evaluation results. If the WBV magnitudes of the ride on forklift trucks in the workplace were less than or comparable to those in the CEN test, the CEN test could be considered useful for the risk assessment of forklift truck operators exposed to WBV. In order to verify the applicability of the CEN test to the evaluation of WBV exposure in the field, we conducted measurements of the WBV of four forklift trucks for 19 d. The trucks had already been examined by the CEN test. The truck velocity, driver position (sitting or not), and gear lever position were also measured, and video footage was obtained for the study. The results indicate that the vertical WBV magnitudes of the four forklift trucks were below the CEN test values. No dominant WBV direction was observed on any of the measurement days. The Health value (obtained by combining the values determined from the vibration in orthogonal coordinates) was comparable to that from the CEN test for one truck. The values for the other three trucks were lower. The data obtained for three forklift trucks were analyzed in each operating condition. The vertical WBV magnitudes and Health values for the three trucks were below the CEN test values when the trucks were travelling forwards with a load. The WBV in the anterior-posterior direction had the largest adverse effect on the human body of the three orthogonal directions when the trucks were used for loading and unloading. The results suggest the CEN test can be applied to the evaluation of exposure to WBV from forklift trucks operating in the vicinity of the Hanshin harbour. It was observed that the anterior-posterior WBV is considerable, mostly through exposure occurring in the lifting mode. However, the CEN test is based on the travelling mode, and further WBV measurements under real working conditions with exact descriptions of detailed work situations and operating conditions are required.

Improvement of the Sitting Position of the Computer Operator Using theToes

Objective: The purpose of this study was to reduce the workload on the computer operator using the toes. Methods: A subject was a 22-years-old man with upper extremity impairments, who worked at a welfare work activity center. The actual duration of computer operation using the keyboard and touch-pad on the desktop was approximately four hours a day. The subject complained of low back pain and lower extremity fatigue at closing time. To alleviate physical load, the working environment was modified as follows. The installation position of the keyboard and touch-pad was moved to the floor. The computer monitor was moved up and close to the operator. A new monitor, a video camera and light aimed at the keyboard were set up for keyboard projection. The effect of this modification was evaluated by a posture analysis, a sitting pressure distribution, a surface electromyogram at the neck and low back, and subjective feelings of the physical load. Results: In accordance with the working environmental modifications, the posture, the sitting pressure distribution, the myoelectric potential, and the physical load of the user improved. Conclusion: Environmental modifications can improve pain and fatigue at closing time and the operability of the computer user.