Respiratory Mechanical and Cardiorespiratory Consequences of Cycling with Aerobars.

Purpose: Aerobars place a cyclist in a position where the trunk is flexed forward and the elbows are close to the midline of the body. This position is known to improve cycling aerodynamics and time trial race performance compared to upright cycling positions. However, the aggressive nature of this position may have important cardiorespiratory and metabolic consequences. The purpose of this investigation was to examine the respiratory mechanical, ventilatory, metabolic, and sensory consequences of cycling while using aerobars during laboratory based cycling. Methods: Eleven endurance trained male cyclists (age=26+/-9 years, V[Combining Dot Above]O2peak=55+/-5 ml/kg/min) were recruited. Visit 1 consisted of an incremental cycling test to determine peak power output. Visit 2 consisted of 6-minute bouts of constant load cycling at 70% of peak incremental power output in the aerobar position, drop position, and upright position while grasping the brake hoods. Metabolic and ventilatory responses were measured using a commercially available metabolic cart and respiratory pressures were measured using an esophageal catheter. Results: Cycling in the aerobar position significantly increased the work of breathing (Wb), power of breathing (Pb), minute ventilation, ventilatory equivalent for oxygen and carbon dioxide, and transdiaphragmatic pressure compared to the upright position. Increases in the Wb and Pb in the aerobars relative to the upright position were strongly correlated with the degree of thoracic restriction, measured as the shoulder-to-aerobar width ratio (Wb: r=0.80, p=0.01; Pb: r=0.69, p=0.04). Conclusions: Aerobars significantly increase the mechanical cost of breathing and leads to greater ventilatory inefficiency compared to upright cycling. Future work is needed to optimize aerobar width to minimize the respiratory mechanical consequences while optimizing aerodynamics. (C) 2017 American College of Sports Medicine

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