The effects of forward rotation of posture on computer-simulated 4-km track cycling: Implications of Union Cycliste Internationale rule 1.3.013.

Abstract

The aim of this research was to indicate improvements in 4-km cycling performance that may be gained as a function of reduced frontal surface area (A) when Union Cycliste Internationale rule 1.3.013 is contravened. In 10 male cyclists age 26 ± 2 (mean ± standard deviation) years, height 180 ± 5 cm and body mass 71 ± 6 kg, entire cycling posture was rotated forward from where the nose of the saddle was 6 cm rearward of the bottom bracket spindle (P₆) to 4, 2 and 0 cm (P₄, P₂ and P₀); contravening Union Cycliste Internationale rule 1.3.013. Using computerised planimetry, A was estimated and a forward integration model was compiled to simulate 4-km track cycling end time (T_4km) when a fixed power profile was applied. At P₂, there was a significant but non-meaningful reduction compared to P₆ (p < 0.05, d < 0.02). There were small but significant reductions in A and T_4km between P₆ and P₀; −0.007 ± 0.004 m² and −1.40 ± 0.73 s, respectively (p < 0.001, d = −0.259). There were no significant differences between P₄ and P₆ for A and T_4km. These results suggest that at the most forward position (P₀), a small but significant increase in 4-km performance can be expected compared to the legal position (P₆). Moreover, the mean difference in T_4km between P₆ and P₀ is greater than the winning margin at the Union Cycliste Internationale 4-km pursuit world championships four times in the previous 10 years.