t measured. Wind velocity is an important variable, as the aero position reduces the wind resistance.5 Our study investigated the physiological response while controlling for environmental factors.
Unlike most other studies, the present research examined performance in both the maximal and a longer steady state exercise setting. Except for Berry et al1 and Gnehm et al,8 who measured response to position in trained subjects at high prolonged intensities, previous research compared the response between positions during brief incremental exercise protocols. Ventilation changes may only become apparent after prolonged exhaustive exercise.1 Body position may therefore only influence physiological variables after a longer period of cycling. Although Berry et al1 found no significant differences between positions during longer duration exercise, Gnehm et al8 observed a significant disadvantage to the aero position during prolonged exercise.
Studies of body position in cycling must attend closely to the experimental position adopted by the participants. Biomechanical efficiency is important when cycling, and a strength of this study is the standardised position assumed by the participants. Too4 suggests that, during cycle ergometry, changing to the aero position can affect the “joint angles, muscle lengths, the muscle arm lengths thus affecting the tension-length, force velocity-power relationship . . . and (therefore) the effectiveness of force production” (286). Both Too4 and Heil et al11 argued that in previous studies, hip angle, a difficult measurement, was not adequately controlled for and therefore not a “true aero position”. In a full forward aero position, where the trunk is parallel to the thighs, the quadriceps may be placed at a disadvantage because of excessive shortening. In the length/tension relation the force obtained may decline at extreme ranges of the muscle. The mechanical advantage/disadvantage is related to how far forward the cyclist is. Jeukendrup and Martin12 state that the aero position may improve aerodynamic drag, but consideration must be given to the impact on joint angle and muscular output. In reality, during competition, most cyclists do not “freeze” in a single position. Rather, the cyclist adjusts to find the most comfortable and/or efficient position (“preferred” versus “optimal” positioning during cycling).11
Take home message
Under standardised conditions, untrained participants who assume the aero position while cycling gain no physiological advantage.
This study provides insight into an untrained physiological response to a standardised aerobar position in the laboratory setting where environmental conditions were closely controlled. It suggests that untrained cyclists cannot assume that their cardiorespiratory function will improve on adopting the aero position. It may be that a period of training and adaptation is necessary to optimise performance using aerobars, although this study was not designed to examine this. The results of this study may be useful in exercise prescription in untrained subjects to assist the best individual performance at an energy efficient cost.
In conclusion, we found evidence of limitation in ventilation in young men cycling in the unfamiliar aerobar position. Inexperience and cycling position is offered to account for the differences observed. Future studies investigating the changes that occur with adaptation and training aerobars would provide valuable information.
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