49.2 Thursday, Jan. 5 Walking in children – the story of an additional gait HUBEL, Tatjana Y*; USHERWOOD, James; Royal Veterinary College, London, UK; Royal Veterinary College, London, UK email@example.com
Observations of walking in small children show that they move quite differently from what one would expect from downsized adults. Human adults are able to drive their legs actively with a frequency about 2-3 times of its passive swing frequency, walking at 4/3rds of the speed achievable with passive swing legs. In contrast, small children – like birds – appear restricted to their passive swing leg frequency, and are limited to lower maximum walking speeds (for their size). Progressing in age, children develop the capability to swing their legs at higher frequencies. In addition, they are able to switch to running in order to achieve higher speeds. Ground reaction forces from children (age 1-5), show typical walking and running profiles, but also a consistent range of intermediates depending on age and speed. We consider these traces in the light of an economical third gait predicted by computer optimization and explore the possibility of powering based on torques, contrasting with adults, and precluded from point mass models.