Cardiovascular and Psychophysical Response to Repetitive Lifting Tasks in Women

Background Understanding the cardiovascular and psychophysical demands of repetitive lifting tasks is important in job design strategies. This study determined the cardiovascular (oxygen consumption (VO2) and heart rate (HR) and psychophysical response to repetitive lifting tasks in women. Methods Ten female (age 27 ± 5 yrs) participants transferred 11.4, 15.9, and 20.5 kg weights back and forth from a rung 40.6 cm high to a rung 156.2 cm high. Rungs were 195.6 cm apart horizontally. Three, 10 minute bouts (1 = 11.4 kg; 2 = 15.9 kg; 3 = 20.5 kg) were performed at 6 lifts per minute. Cardiovascular and psychophysical (rating of perceived exertion, RPE) parameters were monitored throughout the bouts. VO2max and HRmax were determined via a maximal treadmill test. Results VO2, HR, and RPE were significantly different between each work bout (p < 0.01), with each outcome variable increasing as load increased. VO2max and HRmax equaled 46.5 ± 7.5 mL·kg−1·min−1 and 191 ± 11 bpm, respectively. Work at 11.4 kg was performed at 38% VO2max and 63% HRmax; at 15.9 kg at 41% VO2max and 72% HRmax; and at 20.5 kg at 49% VO2max and 81% HRmax. RPE at 11.4, 15.9, and 20.5 kgs were: 8.4 ± 1.6, 11.4 ± 1.9, and 15.0 ± 2.2. Conclusion During these repetitive lifting tasks, metabolic cost and perceived exertion increased with weight lifted; average work intensity ranged from 63 to 81% of HRmax and 38 to 49% of VO2max. Results have important implications in relation to job pacing and design, and worksite health promotion strategies aimed at reducing work place injury.