Most lifting analyses have used static models to evaluate the loading of the trunk during the performance of work. Recent research has reported many differences in trunk muscle force capability when a wide range of trunk velocities are observed. This study focused upon these differences during slow trunk velocities, which would be expected during a lift. Forty-five subjects were tested for their ability to exert torque about their low back under static and dynamic sagittally symmetric lifting conditions. Trunk muscle electromyography was used as a measure of trunk loading. The results reveal that significantly greater loading occurs under slow dynamic conditions, as compared with static conditions. Hence, static models, which assume quasistatic motion, are not good indicators of dynamic trunk load. A regression model was developed that described trunk loading as a function of trunk angle and velocity. The correlation between torque and muscle electromyography in the erector spinae muscles was also found to increase significantly as trunk velocity increased. The implication of these findings upon lifting is discussed.

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In this paper the usefulness of a statistical package developed for analyzing biomechanical data is discussed. The biomechanical data may consist of internal forces such as muscle electromyography as well as external forces such as dynamometer and acceleration information. The package is developed for IBM PC micro-computer and written in Microsoft's Basic programming language. The main feature of this software is that it can determine precisely the time at which each muscular activity starts, by using a slope variation technique. In addition, this software determines the statistical parameters from the starting time of each channel activity until the termination of the task. The software is incorporated with flag indicators so that it can be used easily with various conditions which require various statistical analysis and treatments.

This paper discusses the development of a simulation package for investigating ramp-freeway accidents. Ramp-freeway accidents often occur due to close car following, lack of time for ramp drivers to look for freeway gaps and/or inadequate acceleration lane length. Rear end collisions can occur on ramps because of close car following and differential gap acceptance criterion of ramp vehicle. This software enables the user to vary the characteristics of the ramp vehicles and permits him to conduct a simulation run on conditions which may lead to accidents in the ramp-freeway

Six subjects,all experienced typists, were tested during two full working days in a VDT workstation using two different data presentation modes from hardcopy to screen and split screen -and a mixture of data entry and file maintenance tasks.The results of this exploratory study indicate that looking for more than 80% of the time at the screen when using a split screen as compared to looking less than 40% at the screen when using a hard copy resulted only in small or no additional increases in both the visual and the musculoskeletal discomfort scores. The subjects maintained a similar overall performance for both data presentations. Based on these results we may conclude that 1) the amount of time looking at the screen appears to have no major influence on both visual and musculoskeletal comfort/discomfort, and that 2) a regimen to adequately reduce the work-stress in continuous VDT work should focus on the duration of uninterrupted constrained sitting while the screen viewing time should not be considered as a major factor.