The design of human-powered vehicles has focused exclusively on the aerodynamic properties of the vehicle exceeding 65 mph, it's obvious as to the importance of minimizing aerodynamic drag. But, from an energetics perspective, how a cyclist should be positioned or what body orientation should be assumed to maximize performance is unknown. Changes in body orientation will place the legs at a different angle with respect to the line of gravity, therefore affecting both the hemodynamics of blood flow and force contribution by the body weight. The effect on cycling performance and whether there may be an interaction effect between blood flow hemodynamics and body weight contribution in different body orientation is also unknown. The purpose of this investigation was to determine the effect of changes in body orientation on energy expenditure, cycling duration and total work output.
Too, Danny, "The Effect of Body Orientation on Cycling Performance" (1989). Kinesiology, Sport Studies and Physical Education Faculty Publications. 95.