Predictability of estimated maximal aerobic capacities for manual material handlers using submaximal box lifting and bench stepping tests

Abstract

The purpose of this study was to develop a progressive submaximal manual material handling test that would correspond with standard bench step ergometric testing procedures. The manual material handling test was administered to 18 men employed from two different high frequency manual materl al handling industries. Estimated maximal aerobic capacity, V 02 values obtained from the manual material handling test were compared to those values obtained from the bench stepping test while supporting and not supporting an Oxylog unit that weighs 2.6 kg (5.8 lb). The mean S.D. manual material handling V 02 max of 2.94 ︢0.3 8 L02 /min was not significantly greater (p = 0.0798) than the bench stepping while supporting the Oxylog unit V 02 m. (2.94 ︢0.44 L02/min) and bench stepping while not supporting the Oxylog unit V 02m@ (2.85 ︢0.50 L02/min). Submaximal aerobic capacities obtained from the manual material handling test shared a strong linear relationship with those obtained from the bench step test while supporting the Oxylog unit, mean r2= 0.97 ︢0.03, and from the bench step test while not supporting the Oxylog unit, mean r2= 0.96 ︢0.05, when compared on an individual basis. Predictive metabolic energy expenditure rates were compared to measured metabolic rates recorded during the progressive submaximal manual material handling test. According to Garg's energy equation validation study, the predictive metabolic energy equations were expected to be greater than actual metabolic energy expenditures (Garg 1979). However, this study found the predictive equations to produce values consistently lower (-I.3 to-5.8%) than measured metabolic energy rates. Analysis of variance found no significance in the differences between measured and predictive metabolic energy expenditures for stage 2 (p = 0.6023), stage 3 (p = 0.3755), stage 4 (p = 0.2566) and stage 5 (p = 0.7529). However, these differences were not tested for a longer duration (greater than 15 minute) or more demanding job task. Further studies are necessary to verify whether Garg's equations accurately predict the energy expenditure of industrial employees.