Meeting Abstract

P3.170  Monday, Jan. 6 15:30  A new transducer for multiple-axis force and torque measurements during arboreal locomotion READER, LL*; BARNES, C; WILKINSON, KC; LEE, DV; University of Utah; University of Nevada – Las Vegas; University of Nevada – Las Vegas; University of Nevada – Las Vegas L.Reader@utah.edu

Although vertebrates exploit a multitude of complex three-dimensional environments, research attention has focused largely on terrestrial locomotion. Key assumptions permitting the measurement of force and center of pressure by force platforms (1 – that force is exerted only in the plane of the platform surface and 2 – that feet cannot grasp or adhere to the platform) do not apply to the interactions of feet, hands and other structures on three-dimensional arboreal supports. Arboreal vertebrates actually rely on “violations” of the same assumptions to achieve arboreal locomotion on vertical surfaces or slender branches. Most previous studies have measured force by retrofitting force platforms, but few have addressed torque – especially in all three axes, which may be key of key importance to moving in trees. We have designed and built a new six-axis transducer and system for measuring applied forces and torques on horizontal ladder rungs, which can be arranged to measure forces/torques from vertical or steep climbing. We have validated this design using a climbing bird likely to depend upon torque to a high degree; parrots climb with the help of dextrous grasping feet and also use the beak as a third limb. Our modular transducer design should be appropriate for many other arboreal/scansorial vertebrates. Climbing rungs of different lengths and diameters may be interchanged to enhance our ability to examine these locomotor behaviors in context that adequately captures the complete interaction of the animal with its physical environment. The transducer components are relatively inexpensive – consisting largely of readily available hardware and 3-D printed plastic – which should hopefully inspire new “DIY” manufacturers from the fields of biomechanics and functional morphology.