Hsiang for his guidance, help, encouragement and financial support. I will always be grateful for his efforts to instill me the importance of independent thinking and hard work.
This paper is a study of the metabolic costs of crawling and stoopwalking as performed by trained male and female subjects. After training, male and female subjects crawled and stoopwalked at a range of task speeds and in task postures set at 100, 90, 80, 70, and 60% of each subject's erect stature. It was found that as the task posture became more stooped,… (More)
The purpose of this study was to describe and quantify measured hand forces during floor to knuckle lifting of various loads. Hand forces of five subjects were measured with a strain gauge apparatus for normal and fast speeds of lifting at 1, 4, and 8 l/min. The pattern of hand force over time exhibited peaks in force in the shape of a spike for all fast… (More)
Research efforts to establish manual materials handling (MMH) capabilities of individuals and populations have been conducted for many years. Most of the previous efforts have explored 'standard postures', utilizing two-handed, symmetric, sagittal plane MMH using unrestricted postures. Recognizing that many industrial MMH activities do not utilize 'standard… (More)
An experiment was designed to study the effect of several task variables on the metabolic energy expenditure and heart rate of individuals performing lifting and lowering tasks. The task variables studied were: load of lift (lower), frequency of lift (lower), height of lift (lower), presence of absence of handles, container height, container width (in the… (More)
For approximately three decades, researchers have utilized psychophysics to develop guidelines (weights, forces and frequencies) for manual materials handling tasks. Early work by Stover Snook and his colleagues provided the foundations of the experimental methodologies that would be used by other researchers as well as design data that would be used by… (More)
A biomechanical evaluation of lifting speed was conducted in the laboratory. The study investigated the effects of lifting speed on several predetermined biomechanical cost functions. The lifting tasks consisted of five lifting speeds labelled as the slowest, slow, normal, fast and fastest, and three weights, 50, 65 and 80% of their maximum acceptable… (More)
The effect of time on an individual's lifting capacity over extended periods using a psychophysical approach was studied. Twelve male subjects estimated their lifting capacity in a 25 min period, and then attempted to lift this weight for an 8 h period under varying conditions. For one experimental condition the subjects were allowed to adjust the weight,… (More)