Cycling rate is modulated by optic flow in a virtual bicycle environment

Manipulation of optic flow using virtual environments (VE) is known to modulate walking speed. We developed a virtual reality augmented cycling system and sought to determine if manipulation of optic flow modified cycling rate. We tested three groups of healthy subjects (n = 5∶5∶3) as they cycled in a virtual park environment while we modified the gain for optic flow (gain at equal, and higher than comfortable cycling speed) using three protocols: 1) bike un-coupled with the VE and perceived gain, 2) bike coupled with VE and perceived gain and 3) bike coupled with VE and constant gain. We found that cycling speed increases were greatest when the bike was coupled with the VE and the gain was constant (F=5.207, p=0.028). Cycling rate increased with optic flow, which differs from the inverse relationship of optic flow and walking. To our knowledge this is the first study to provide preliminary evidence on cycling rate responses to optic flow.