Degeneracy of the perceptual-motor system for aperture crossing in cycling

Cycling requires individuals to perceive which behaviour are possible and which are not, and select the most appropriate behaviour among available possibilities to perform successfully. This study investigated whether and how cyclists with different crossing abilities exploit perceptual-motor system degeneracy to cross narrower aperture widths, in particular whether cyclists with higher crossing ability exploit degeneracy by using more complex action modes to cross narrower aperture widths. Fifteen participants whose crossing ability ranged from -16 cm to +2 cm in relation to the bike handlebar width were observed as they crossed different aperture widths. Handlebars' turning and bike' lean' angles were recorded using a Qualisys system and were extracted at the moment of crossing to determine different action modes: facing, leaning, turning, and a combination of turning and leaning. Data revealed that cyclists exploit different actions modes between and within aperture width conditions, confirming the exploitation of degeneracy property. However, skills of the cyclists with lowest maximal action capability were confined to the relatively simple modes of action, restricting their ability to cross narrower apertures and to be less successful when acting close to their action boundaries. On the other side, cyclists with highest maximal action capability adapted to task constraint by using more complex action modes, which allowed them to be successful when acting close to their action boundaries.