Effects of Workrate and Seat Position on Frontal Plane Knee Biomechanics in Recumbent Cycling

In cycling study, most of the research focused on the sagittal plane lower extremity biomechanics and upright cycling. However, few of them paid attention to the frontal plane and recumbent cycling. Internal knee abduction moment (KAbM), on the frontal plane, has been shown to be an effective predictor of knee osteoarthritis (OA), and recumbent bicycle has become the newest popular tool of rehabilitation. The purpose of this study was to examine the effects of different workrates and seat positions on knee frontal plane biomechanics during stationary recumbent cycling. Thirteen participants took part in the study. 6 total conditions of one-minute cycling at the cadence of 80 RPM were assigned to each participant: pedaling at “flexed”, “optimal” and “extended” seat positions (largest knee extension angle of 10-20 degrees, 20-30 degrees, and 30-40 degrees, respectively) with 60 and 100 W of workrate. A 3D motion analysis system and a pair of custom-made instrumented pedals were used to collect kinematic and kinetic data.