Muscular efficiency during arm cranking and wheelchair exercise: a comparison

The present study was performed to compare various individual muscular efficiency indices, i. e., gross (GE), net (NE), work (WE), and delta (DE), during arm cranking ergometer (ACE) and wheelchair ergometer (WERG) exercise at the same relative exercise intensities. Following a maximal test on both the ACE and WERG, 15 able-bodied subjects completed 4 submaximal bouts at 0, 40, 55 and 70 % of the mode-specific VO(2) peak. The peak power output and VO(2) values were significantly higher with ACE than WERG maximal exercise. As a consequence, the power output imposed during WERG submaximal bouts was significantly lower compared to ACE submaximal bouts. ACE exercise was found to elicit a significantly higher (p < 0.001) VO(2) (16 to 28 vs 14 to 23 ml x min(-1) x kg(-1)), GE (9 to 11 vs 6 to 9 %) and NE (14 to 13 vs 10 to 11 %) compared to WERG exercise at power output from 40 to 70 % VO(2) peak, respectively. However, WE (17 to 15 vs 17 to 14 % at 40 to 55 % VO(2)peak) and DE (12 to 13 vs 12 to 12 % at Delta 40 - 55 % to Delta 55 - 70 % VO(2) peak) values were similar between ACE and WERG exercise. The lower GE and NE observed during WERG compared to ACE exercise could be explained by the biomechanical disadvantages of the hand-rim WERG pattern movement. These findings also supported that the different indices of efficiency influenced the interpretation of the comparison between ACE and WERG propulsion.