Pedaling cadence variability increases by worsening the bike fitting across most but not all workloads

Abstract

Cyclic motion variability reflects the movement error correction. Since movement motor control generally worsens with impaired biomechanical setups, we assessed whether the pedaling cadence variability (PCV) increases by worsening the bike fitting across multiple workloads. Sixteen cyclists performed multiple 5-min bouts of constant load cycling exercise at 0, 20, 40, 55, 70, 85% of their maximum workload (MWL) capacity at 60 rpm with proper (PROPER) and worsened (WORSENED; 15 cm saddle height drop) bike fittings. Cycle-by-cycle duration series were collected. PCV was calculated as the standard deviation of each series. In both PROPER and WORSENED, PCV showed a U-shaped feature by increasing workload (minimum PCV values at 55% MWL). PCV was higher in WORSENED than PROPER, except at 55% MWL (0% MWL: 36.69 ± 10.06 vs. 42.21 ± 11.3, p < 0.01; 55% MWL: 18.87 ± 3.51 vs. 19.74 ± 4.73, p = 0.3; 85% MWL: 34.93 ± 10.51 vs. 39.52 ± 11.84, p < 0.01; ms; PROPER vs. WORSENED, respectively). PCV seems to be a workload-dependent variable, being greater at low and high workloads. At intermediate workloads, the moderate force expression to continue the movement, along with the effect of the workload itself in counteracting the natural extension of the leg, might explain a lower need for continuous motion adjustments and, consequently, a lower PCV in both bike setups.