Full Motion Capture of Bicycle Riding on a Treadmill

Jan 9-11, 2009: For three days we have been doing full motion capture of the rider and the bicycle while riding on the large(3X5 m) VU Amsterdam treadmil. This to investigate rider motions on a bicycle. The Optotrack Certus Motion Capture System with active markers was used (thanks to the VU!) with 31 markers (20 on the rider, 11 on the bicycle) at a sample freq of 100 Hz. The test comprised: normal pedalling, towing, hands-free pedalling, pedalling with line tracking. The belt speed (=forward bicycle speed) was varied from 5 to 30 km/h in steps of 5 km/h and then down in the same manner. At every speed we measured for 60 seconds. Going down we also tried 5,4,3,2,.. km/h until one could not stabilize any more. Every test was done with three riders and two bicycles form Batavus, the Browser and a Stratos.

image14 image15 Here you see Jodi geared-up with 20 markers and a safety harness on the Batavus Stratos riding on the VU treadmill. Below you see a video of Jason on the same bicycle in a pedalling run at 10 km/h and to the right of that a visualisation of the marker motions for that same run. We analyze the large data sets by Principal Component Analysis.
Jason, pedalling, Batavus Stratos, 10 km/h Measured marker motions same run