Evaluation of anaerobic threshold for lifting tasks
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An experiment was designed and conducted to accomplish the following objectives: 1. Comparison of the maximum V02 values, as measured during an arm cycling task, a bicycling task, and lifting activities, 2. Comparison of the anaerobic threshold (AT), as measured during an arm cycling task, a bicycling task, and lifting activities, 3. Development and testing of a mathematical model for the prediction of the lifting capacity using the criterion of an individualâ€™s anaerobic threshold. A submaximal exercise protocol was applied to predict the aerobic capacity (V02 max or PWC). A graded exercise protocol using successive weight increments was applied to predict the AT. The dependent variables were the predicted maximum permissible (lbs.) of lift at 90% of the AT and the anaerobic threshold (1/min. of O2). The independent variables were task and individual variables. The task variables were ranges of lift (floor to knuckle height and knuckle to shoulder height) and frequencies of the lift (6, 7.5, and 9 lifts/min). The individual variables included body weight, lean body weight, and the PWC values predicted from bicycling and arm cycling. Ten make subjects, 10-27 years of age, participated in the experiment. The collection of physiological data began after a familiarization period. The results of the experiment were analyzed using the analysis of variance procedure. The predictive models were developed for each range of lift using a stepwise multiple linear regression technique. The models to predict lifting capacity of an individual were validated using three additional subjects. It was concluded that the models can reasonably predict lifting capacity based on the steady state of V02 and heart rate responses achieved during a 30 minute constant-load validation experiment. The predicted lifting capacity was also well within the 95th percentile of published lifting capacity norms. It was also concluded that the AT values were discretely related to the active muscle mass utilized in performing a physical task.