METABOLIC EFFICIENCY DURING ARM AND LEG EXERCISE AT THE SAME RELATIVEINTENSITIES

This study was conducted to compare gross efficiency (GE), net efficie ncy (NE), work efficiency (WE), and delta efficiency (DE) between arm crank and cycle exercise at the same relative intensities. Eight colle ge-aged males underwent two experimental trials presented in a randomi zed counterbalanced order. During each trial subjects performed three intermittent 7-min exercise bouts separated by 10-min rest intervals o n an arm or semirecumbent leg ergometer. The power outputs for the thr ee 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) o f total energy expended, energy expended above rest and energy expende d above unloaded exercise, respectively. DE was determined as the rati o of the increment of Kcal . min(-1) of power output above the previou s lower intensity to the increment of Kcal . min(-1) of total energy e xpended above the previous lower intensity. GE and NE did not differ b etween arm crank and cycle exercises. However, WE was lower (P < 0.05) during arm crank than cycle exercise at 50, 60, and 70% V over dot(2p eak). DE was also lower (P < 0.05) during arm crank than cycle exercis e at Delta 50-60 and at Delta 60-70% V over dot(2peak). It is conclude d metabolic efficiency as determined by work and delta efficiency indi ces was lower during arm crank compared with cycle exercise at the sam e relative intensities. These findings add to the understanding of the difference in metabolic efficiency between upper and lower body exerc ise.