Lower-Limb Kinematics Changes During a 20 km Time Trial of Experienced Master Cyclists

Evaluating cyclists’ lower limbs across all three planes of motion in conditions that resemble real-world cycling scenarios is essential for a comprehensive analysis aimed at optimizing performance through improved bike positioning and preventing movement patterns associated with joint overload. Nine cycling athletes with at least five years of competitive experience participated in this study. They completed a 20 km time trial on bicycles attached to a cycle trainer with a configured flat course. Thirty markers were placed on the lower limbs to calculate the hip, knee, and ankle angles, using 11 Optitrack cameras around the participants. Statistical Parametric Mapping was applied to detect subtle yet meaningful variations in joint angles throughout the entire crank cycle, comparing the following stages: $5 \mathrm{~km}, 10 \mathrm{~km}, 15 \mathrm{~km}$, and 20 km. Significant differences were found in the hip and ankle joints in the sagittal plane across conditions. Hip flexion increased during the 20 km section compared to 5 km and 15 km, while ankle dorsiflexion was greater at 20 km compared to 10 km and 15 km. Experienced master cyclists exhibit changes in their kinematic patterns throughout a 20 km time trial, particularly in the sagittal plane. A high variability in movement within the other planes was observed, consistent with previous literature. This is the first study to analyze lower-limb 3D kinematics during a 20 km time trial, highlighting the need for further research on cyclists with different training levels.