The Effect of Pedal Platform Height on Cycling Biomechanics

Abstract

Using a five-bar linkage model of the leg/bicycle system in conjunction with experimental kinematic and pedal force data, the inverse dynamics problem is solved to yield the intersegmental moments. Among the input data that affect the problem solution is the height of the pedal platform. This variable is isolated and its effects on the total joint moments are studied as it assumes values over a ±4-cm range. Platform height variation affects the total joint moment peak values by up to 13%. Relying on a cost function derived from the hip and knee moments, it is found that the platform height that minimizes the cost function is +2 cm. The sensitivity of the cost function to the platform height variable is low; over the variable range the cost function increases 2% above the minimum. These results hold for a pedaling rate of 90 rpm. As pedaling rate is varied above and below 90 rpm, the sensitivity of the cost function increases. The platform heights that minimize the cost function are the lower and upper limits for 60 and 120 rpm, respectively. Thus the platform height variable interacts with pedaling rate, requiring a compromise in platform height adjustment. The compromise height depends on the individual’s preferred pedaling rate range.

Development of a Low-Cost Measurement System to Determine 3-Dimensional Pedal Loads During in-Situ Cycling

“…-The vertical distance between footplate and spindle is between 10 and 20 mm to adapt a normal pedal movement [7]. -The vertical distance between the underside of the pedal and spindle is at least 20 mm to prevent hitting the ground when turning.…”

“…The design was cumbersome and therefore only applicable on stationary bicycles in the laboratory environment. In the past decades, several new pedal sensors were developed, though they share a number of shortcomings: (i) they measure only the normal and anterior forces, ignoring the lateral ones that are accountable for severe knee injuries [3 -6]; (ii) they are too bulky and therefor limited to the laboratory environment which is not representative for in-situ cycling [3,4,7]; and (iii) they lift the foot too far above the pedal spindle which influences the cyclist's pedal technique [7]. For the racing industry, multiple compact instrumented pedals are placed on the market that measure power output [8].…”

A New Crank Arm-Based Load Cell for the 3D Analysis of the Force Applied by a Cyclist

“…By applying a force to the pedal, the cyclist generates a rotating motion of the crank arm around the crankset axle. The biomechanical studies about this applied force became popular after the studies of Hull et al [ 6 – 8 ], when an instrumented pedal capable of measuring the force components in 3D was proposed, enabling the development of more advanced kinetic models. The force applied to the pedal is transferred to the crank arm, and it can be decomposed into three main components, as shown in Figure 1 : Perpendicular to the crank arm, acting in the rotation plane.…”

Methods for Determining Hip Movement in Seated Cycling and Their Effect on Kinematics and Kinetics

“…Direct correspondence to M,L. Hull. Gonzalez, 1990) and the trochanter (TRO) method (e.g., van Ingen Schenau, Van Woensel, Boots, Snackers, & deGroot, 1990).…”