Maximum acceptable work time for the upper and lower limbs tasks

Abstract

Introduction: The physical workload is one of the major risk factors for the workers. At present the proposed methods to assess physical dynamic work load contemplate working with the whole body and not discriminate on body segments. Objective. Determine the maximum acceptable dynamic work time when the work is with the whole body, with the upper and lower limbs. Methods. Oxygen consumption was measurement by ergospirometry and heart rate was monitoring in 30 workers exposed to various loads executed with the whole body, legs and upper limbs. Anaerobic threshold was determined by respiratory quotient, this was used by calculate the acceptable dynamic work time. Results. Statistically significant differences between acceptable dynamic work time for upper limbs and lower limbs were found. Negative exponential correlation model was found between the time the work load and the oxygen consumption and heart rate, R> 0.9 in all cases. Nine regression equations were proposed to determine the acceptable dynamic work time. Conclusions. The acceptable dynamic work time for lower limbs and whole body is similar. The acceptable dynamic work time with upper limbs is significantly lower than the previous. The relative heart rate seems to be the best indicator to measure acceptable dynamic work time.