Body size as a determinant of the 1-h cycling record at sea level and altitude

Daniel P. Heil

This study was designed to validate models for predicting the two Union Cycliste Internationale (UCI) classifications for the 1-h cycling record at sea level and altitude. Specific attention was paid to the integration of model components that were sensitive to scaling differences in body mass (m(b)). The Modern Aero Position model predicted UCI Best Hour performances using predictions of total projected frontal area (A(P)) that included use of an aerodynamic bicycle and aerodynamic handlebars. The Traditional Racing Position model predicted UCI Hour Record performances using predictions of total A(P) that include use of a "Merckx-era" bicycle with drop-style handlebars. Prediction equations for A(P), as well as the coefficient of drag and metabolic power output , involved scaling relationships with m(b), while other model components were similar to previously published 1-h models. Both models were solved for the distance cycled in 1 h (D(HR)) using an iterative strategy. Chris Boardman's current records for the UCI Best Hour Performance (56.375 km) and the UCI Hour Record (49.202 km) were underpredicted by only 0.332 km (-0.6%) and 0.239 km (-0.5%). Both models, regardless of altitude, suggested that D(HR) should scale with m(b) to the +0.174 power (D(HR) alpha m(b) (+0.174)), which is lower than the +0.32 exponent recently suggested in the literature. Lastly, the same models also predicted that six-time Tour de France winner, Lance Armstrong, could exceed both of Boardman's current records at sea level by about 2.0 km.