Physiological analysis of repetitive lifting.

It was hypothesized that physical factors associated with the act of lifting, and also known to adversely affect cardiovascular functions (e.g., increased intrathoracic and intraabdominal pressures), would disturb the linear relationships normally noted among measures of cardiopulmonary variation during exercise. Data collected during repetitive lifting, performed on a unique ergometer (described in the paper), did not support the hypothesis. It was concluded that relationships among energy expenditure rate, pulmonary ventilation, heart rate, and workload were essentially linear through the range of lifting workloads from 1 to 50 W for 18 male Caucasians ranging in age from 21 to 55 years.