Meeting Abstract

3.3  Tuesday, Jan. 4  The effects of uneven terrain on Galliformes running mechanics BIRN-JEFFERY, A.V.*; DALEY, M.A.; The Royal Veterinary College, UK; The Royal Veterinary College, UK abirnjeffery@rvc.ac.uk

Galliformes are a diverse group of ground dwelling birds who are capable runners. These birds are valuable for comparative biomechanics studies because they span a large range in body size, leg morphology and habitats. We are using galliform birds to investigate the neuro-mechanical, stability and energy management mechanisms used to negotiate uneven terrain. Here we compare locomotor strategies used by Galliformes across a range of uneven terrain. We hypothesise that different species will use different strategies to run in uneven terrain, depending on their morphology. In particular, we expect small ‘crouched’ birds to use more passive mechanisms than larger birds. We are testing this hypothesis by comparing several galliform species. We collected kinetic and kinematic data as birds ran across six terrain conditions of varying ‘roughness’, using level terrain as control. Each uneven terrain condition contained obstacles of a single height; from 10-50% leg length (L_leg), spaced 2 strides apart. CoM height greatly fluctuates in uneven terrain; at 0.3 L_leg obstacles the potential energy increases by 57% of the obstacle height. Swing leg dynamics appear to determine the mechanics of stance phase; earlier arrival at apex is followed by a shorter stance period. Leg angles at touchdown and take off events do not significantly deviate from level. This suggests leg angular trajectory may be a controlled variable in galliform locomotion. During both level and uneven terrain running significant torsional and axial actuation is used during the stance phase. Developing an understanding of neuro-mechanical mechanisms over changing terrain ‘roughness’ will allow better development of models for robustly stable locomotion that would improve the performance of legged robots and prosthetics.