Analysis of Movement Variability in Cycling: An Exploratory Study

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Understanding movement variability is crucial for optimizing cycling performance and injury prevention.
• Traditional motion capture systems like VICON Nexus are effective but can be costly and less portable.
• Inertial measurement units (IMUs) offer a potential alternative for analyzing movement dynamics.

Purpose of the Study:

• To assess the test-retest reliability of Blue Trident IMUs and VICON Nexus kinematic modeling for Lyapunov Exponent (LyE) analysis in cycling.
• To investigate changes in LyE across a 4000m maximal cycling effort.
• To compare the performance of IMUs and VICON Nexus in analyzing movement variability.

Main Methods:

• Twelve novice cyclists performed a 4000m maximal cycling effort across four sessions.
• IMUs were placed on the head, thorax, pelvis, and shanks to measure segment acceleration.
• VICON Nexus captured segment/joint angular kinematics using reflective markers.
• Lyapunov Exponent (LyE) was calculated for both IMU acceleration and VICON Nexus kinematics.

Main Results:

• Test-retest reliability for both IMUs and VICON Nexus varied from poor to excellent across different body segments.
• LyE of head and thorax IMU acceleration increased during the cycling bout, while pelvic and shank LyE remained consistent.
• VICON Nexus showed session differences in kinematics, but no consistent trend was observed.
• IMUs demonstrated improved reliability and identified consistent trends in movement variability.

Conclusions:

• IMUs provide reliable and consistent analysis of movement variability in cycling, particularly for head and thorax segments.
• IMUs are a more portable and cost-effective option compared to VICON Nexus for cycling biomechanics.
• Further research is needed to fully establish the applicability of IMUs for analyzing movement variability in diverse cycling contexts.