The effects of arm crank strategy on physiological responses and mechanical efficiency during submaximal exercise

Abstract

The purpose of this study was to compare submaximal physiological responses and indices of mechanical efficiency between asynchronous and synchronous arm ergometry. Thirteen wheelchair-dependent trained athletes performed eight steady-state incremental bouts of exercise (0 to 140 W), each lasting 4 min, using synchronous and asynchronous arm-cranking strategies. Physiological measures included oxygen uptake (VO2), heart rate, and blood lactate concentration. The power outputs corresponding to fixed whole blood lactate concentrations of 2.0 to 4.0 mmol x l(-1) were calculated using linear interpolation. Mechanical efficiency indices - gross efficiency, net efficiency, and work efficiency - were also calculated. An analysis of variance with repeated measures was applied to determine the effect of crank mode on the physiological parameters. Oxygen uptake was on average 10% lower (P < 0.01), and both net efficiency (P < 0.01) and gross efficiency (P < 0.01) were higher, during the asynchronous strategy at both 60 and 80 W (gross efficiency: 16.9 +/- 2.0% vs. 14.7 +/- 2.4% and 17.5 +/- 1.8% vs. 15.9 +/- 2.6% at 60 and 80 W respectively). There were no differences in heart rate, blood lactate concentration or power output at either of the blood lactate reference points between the asynchronous and synchronous strategies (P > 0.05). In conclusion, test specificity is an important consideration. If a synchronous strategy is to be adopted, it is likely to result in lower efficiency than an asynchronous strategy. The exercise testing scenario may help dictate which method is ultimately chosen.

Effects of type and mode of propulsion on hand-cycling biomechanics in nondisabled subjects

“…Generally, studies on physiological responses between AC and SC arm-crank ergometry reveal no difference between the two crank modes [14][15][16]. Moreover, a recent study by GooseyTolfrey and Sindall finds significantly higher efficiencies during submaximal AC versus SC mode of propulsion in subjects who were wheelchair-dependant trained [17]. In contrast to previous results in arm-crank ergometry, different investigations show that SC hand cycling is less strenuous and more efficient than AC hand cycling [18][19][20][21][22][23].…”

The influence of crank length and cadence on mechanical efficiency in hand cycling

“…The limited studies to date have provided further support to the notion that ME is altered with changes in cadence (Marais et al 2002;Verellen et al 2004) or the use of synchronous and asynchronous crank patterns (Hopman et al 1995;Abel et al 2003;Dallmeijer et al 2004;Goosey-Tolfrey and Sindall 2007). Research has yet to be conducted with respect to varying crank length, ideally in a similar experimental paradigm to that described by Martin and Spirduso (2001) which also combined cadence.…”

“…Hand cycling has become increasingly popular at both a sports performance level and as an exercise modality for improvements in general health and fitness (Maki et al 1995;Goosey-Tolfrey and Sindall 2007). At a recreational level, hand cycle units can be attached to a wheelchair, lifting the front castors from the floor, allowing the wheelchair to be propelled with the arms in a continuous cycling action with the aid of a gearing system ( Van der Woude et al 2001;Verellen et al 2004).…”

Submaximal arm crank ergometry: Effects of crank axis positioning on mechanical efficiency, physiological strain and perceived discomfort

“…However, the results found by Miller et al [23] have to be viewed with caution, since they used data from the first or second minute of an exercise bout, where it is likely that a steady state is not yet established. Further, data were obtained by asynchronous arm ergometry, which, as described earlier, seems to be less straining compared to synchronous arm ergometry [14,15].…”

“…In arm cranking, both synchronous and asynchronous propulsion modes are used. The research of Goosey-Tolfrey & Syndall [14] and Hopman et al [15] showed that during submaximal arm cranking, an asynchronous propulsion mode is more efficient and less straining compared to a synchronous propulsion mode, which is in contrast to hand cycling results [13,16]. The fact that no steering is involved in arm crank ergometry as opposed to hand cycling could be the cause for these differences [13,17].…”