Comparison of static and dynamic methods based on knee kinematics to determine optimal saddle height in cycling

Abstract

Bike-fitting methods based on knee kinematics have been proposed to determine optimal saddle height. The Holmes method recommends that knee angle be between 25° and 35° when the pedal is at bottom dead centre in static. Other authors advocate knee angle of 30-40° during maximum knee extension while pedalling. Although knee angle would be 5-10° greater at bottom dead centre during pedalling, no study has reported reference values in this condition. The purpose of this study was to compare these three methodologies on knee, hip, and ankle angles and to develop new dynamic reference range at bottom dead centre. Methods: Twenty-six cyclists volunteered for this experiment and performed a pedalling test on their personal road or mountain bike. Knee, hip, and ankle angles were assessed by two-dimensional video analysis. Results: Dynamic knee angle was 8° significantly greater than static knee angle when the pedal was at bottom dead centre. Moreover, dynamic knee angle with the pedal at bottom dead centre was 3° significantly greater than dynamic knee angle during maximum knee extension. The chosen methodology also significantly impacted hip and ankle angles under most conditions. Conclusions: The results allow us to suggest a new range of 33-43° when the pedal is at bottom dead centre during pedalling. Thus, this study defines clearly the different ranges to determine optimal saddle height in cycling according to the condition of measurement. These findings are important for researchers and bike-fitting professionals to avoid saddle height adjustment errors that can affect cyclists' health and performance.

Effects of workload and saddle height on muscle activation of the lower limb during cycling

“…Although many studies begun to focus on the role of knee angle in bike fitting, joint angle seems to be more affected by riding techniques and other bike settings such as crank and frame [ 51 ]. And there is a 5° to 10° difference between static and dynamic joint angles [ 52 , 53 ]. Therefore, bike fitting based on anthropometry is still the mainstream way and research focus.…”

Validity of Neural Networks to Determine Body Position on the Bicycle

“…We based our sample size calculation at the intention to determine a minimum difference of 5 in angles, which is at the centre of the range proposed to determine body position on the bicycle (i.e. 10, Millour et al, 2019;. We also assumed that the within-cyclist's variability in angles would be 3.4 , resulting in an effect size of 1.47.…”

A literature overview of modern biomechanical-based technologies for bike-fitting professionals and coaches

“…For each body segment, the International Society of Biomechanics has proposed standards for joint coordinate systems in order to analyze human joint motion. 17,18 Joint kinematics is influenced by several factors: bike configuration, 19,20 cleat adjustment, 21 condition of measurement (i.e., static vs. dynamic), 22 pedalling technique, 23 fatigue rate 24 and workload. 25 Therefore, it is now advisable to carry out joint kinematic measurements with motion capture systems during pedalling at intensities close to those experienced during training and racing.…”