Cycling performance in human powered vehicles is affected by the interaction of a number of variables, including environment, mechanical and human factors. Engineers have generally focused on the design and development of faster, more efficient human-powered vehicles based on minimising aerodynamic drag, neglecting the human component. On the other hand, kinesiologists have examined cycling performance from a human perspective, but have been constrained by the structure of a standard bicycle. Therefore, a gap exists between research in the various disciplines. To maximise/optimise cycling performance in human-powered vehicles requires a bridging of this gap through interdisciplinary research. Changes in different variables can affect the energy requirements of cycling. These variables include: (a) changes in body position, configuration, and orientation; (b) changes in seat to pedal distance; and (c) the interaction of workload, power output, and pedalling rate. Changes in these variables alter joint angles, muscle lengths, and muscle moment arm lengths, thus affecting the tension-length, force-velocity-power relationships of multi-joint muscles and the effectiveness of force production. This is ultimately manifested as a change in the energetics of cycling. A large number of factors affect cycling performance in human-powered vehicles and a gap still exists between cycling research in various disciplines. To bridge this gap, if not completely close it, requires cooperation between disciplines and further interdisciplinary research.