Rammohan V Maikala1, Yagesh N Bhambhani. 1. Liberty Mutual Research Institute for Safety, 71 Frankland Road, Hopkinton, MA 01748, USA. rammohan.maikala@libertymutual.com
Abstract
OBJECTIVE: Peak cardiorespiratory, metabolic, and perceptual responses in healthy men (n=11) and women (n=11) were compared during two different upper body exercise modes: standardized arm cranking and task-specific pushing-pulling. METHODS: Each subject completed to volitional exhaustion both an incremental arm cranking and a pushing-pulling exercise continuously, in a random order, on two separate days. Physiological responses were monitored using an automated metabolic cart and a heart rate monitor, and the rating of perceived exertion was obtained using a 15-point Borg Scale. RESULTS: Peak oxygen uptake, oxygen pulse, respiratory exchange ratio, and ventilation rate were higher and total exercise time to exhaustion was lower during arm cranking compared to pushing-pulling (P<0.05). However, heart rate was similar between exercise modes (P>0.05). Men showed greater physiological responses (absolute oxygen uptake, oxygen pulse, and ventilation rate) and longer exercise time to exhaustion than women (P<0.05). Power output during arm cranking was higher (by 79%) than pushing-pulling (P<0.01), with men demonstrating 30% greater values during both exercise modes (P<0.01). The lower power output generated during pushing-pulling resulted in a greater ratio of peak oxygen uptake to power output (by 72%; P<0.05). Interestingly, although power output and oxygen uptake were lower at the maximal workload, perceived exertion was higher (by 5%) during pushing-pulling (P<0.05). CONCLUSIONS: Based on the physiological differences, pushing-pulling is found to be metabolically less efficient than arm cranking. However, greater ratings of perceived exertion during pushing-pulling implies that the perception of effort can also be influenced by a low intensity task, such as pushing-pulling, if performed for a prolonged period. Occupational health professionals should be aware of the limitations of utilizing physiological and perceptual responses obtained only from standardized ergometric protocols in predicting the workers' performance effectiveness.
OBJECTIVE: Peak cardiorespiratory, metabolic, and perceptual responses in healthy men (n=11) and women (n=11) were compared during two different upper body exercise modes: standardized arm cranking and task-specific pushing-pulling. METHODS: Each subject completed to volitional exhaustion both an incremental arm cranking and a pushing-pulling exercise continuously, in a random order, on two separate days. Physiological responses were monitored using an automated metabolic cart and a heart rate monitor, and the rating of perceived exertion was obtained using a 15-point Borg Scale. RESULTS: Peak oxygen uptake, oxygen pulse, respiratory exchange ratio, and ventilation rate were higher and total exercise time to exhaustion was lower during arm cranking compared to pushing-pulling (P<0.05). However, heart rate was similar between exercise modes (P>0.05). Men showed greater physiological responses (absolute oxygen uptake, oxygen pulse, and ventilation rate) and longer exercise time to exhaustion than women (P<0.05). Power output during arm cranking was higher (by 79%) than pushing-pulling (P<0.01), with men demonstrating 30% greater values during both exercise modes (P<0.01). The lower power output generated during pushing-pulling resulted in a greater ratio of peak oxygen uptake to power output (by 72%; P<0.05). Interestingly, although power output and oxygen uptake were lower at the maximal workload, perceived exertion was higher (by 5%) during pushing-pulling (P<0.05). CONCLUSIONS: Based on the physiological differences, pushing-pulling is found to be metabolically less efficient than arm cranking. However, greater ratings of perceived exertion during pushing-pulling implies that the perception of effort can also be influenced by a low intensity task, such as pushing-pulling, if performed for a prolonged period. Occupational health professionals should be aware of the limitations of utilizing physiological and perceptual responses obtained only from standardized ergometric protocols in predicting the workers' performance effectiveness.