Metabolic efficiency during arm and leg exercise at the same relative intensities

Abstract

This study was conducted to compare gross efficiency (GE), net efficiency (NE), work efficiency (WE), and delta efficiency (DE) between arm crank and cycle exercise at the same relative intensities. Eight college-aged males underwent two experimental trials presented in a randomized counterbalanced order. During each trial subjects performed three intermittent 7-min exercise bouts separated by 10-min rest intervals on an arm or semirecumbent leg ergometer. The power outputs for the three bouts of arm crank or cycle exercise corresponded to 50, 60, and 70% of the mode-specific VO2peak. GE, NE, and WE were determined as the ratio of Kcal.min-1 equivalent of power output to Kcal.min-1 of total energy expended, energy expended above rest and energy expended above unloaded exercise, respectively. DE was determined as the ratio of the increment of Kcal.min-1 of power output above the previous lower intensity to the increment of kcal.min-1 of total energy expended above the previous lower intensity. GE and NE did not differ between arm crank and cycle exercises. However, WE was lower (P < 0.05) during arm crank than cycle exercise at 50, 60, and 70% VO2peak. DE was also lower (P < 0.05) during arm crank than cycle exercise at delta 50-60 and at delta 60-70% VO2peak. It is concluded metabolic efficiency as determined by work and delta efficiency indices was lower during arm crank compared with cycle exercise at the same relative intensities. These findings add to the understanding of the difference in metabolic efficiency between upper and lower body exercise.

Heavy reliance on carbohydrate across a wide range of exercise intensities during voluntary arm ergometry in persons with paraplegia

“…Certainly, the smaller mass of musculature in the upper body and consequent 25-30% lower VO 2peak achieved during upper vs. lower body exercise 21 would translate to significantly lower maximal rates of whole body fat and CHO oxidation. Additionally, lower metabolic efficiency 20 and lower oxygen extraction 22 may explain the heavy reliance on CHO found in this study.…”

“…However, when the non-disabled subjects of this study performed the same continuous progressive voluntary arm ergometer test as the subjects with paraplegia, they only reached a maximal WBFO rate of 0.06 ± 0.04 g/minute at 13 ± 3% VO 2peak . Differences in substrate partitioning between upper and lower body exercise have primarily been examined in non-disabled individuals 20 and are complicated by large differences in VO 2peak between the two modes of exercise. Certainly, the smaller mass of musculature in the upper body and consequent 25-30% lower VO 2peak achieved during upper vs. lower body exercise 21 would translate to significantly lower maximal rates of whole body fat and CHO oxidation.…”

Effect of preceding resistance exercise on metabolism during subsequent aerobic session

“…The protocol was similar to what was reported previously (Kang et al 1997). Briefly, the test was preceded by a 5-min warm-up period.…”

Regulating intensity using perceived exertion: effect of exercise duration

“…The protocol used for the cycle test is outlined in Kang et al (1997). BrieXy, this protocol requires the subject to pedal at 60 rev min ¡1 and an initial power output of 50 W. The power output was then increased every 2 min by 25 W for women and 50 W for men.…”