Limb kinematics and inverse dynamic modelling of jumping in the red-legged running frog (Kassina maculata)


Meeting Abstract

127-5  Thursday, Jan. 7 14:30  Limb kinematics and inverse dynamic modelling of jumping in the red-legged running frog (Kassina maculata) PORRO, LB*; COLLINGS, AJ; CHADWICK, KP; RICHARDS, CT; Royal Veterinary College, Hatfield, UK; Royal Veterinary College, Hatfield, UK; Royal Veterinary College, Hatfield, UK; Royal Veterinary College, Hatfield, UK lporro@rvc.ac.uk http://www.rvc.ac.uk/about/our-people/laura-porro

Although the skeletal morphology of anurans is adapted for jumping, frogs engage in a range of locomotor behaviours. Kassina maculata, thought to be specialized for walking and running compared to other frog taxa, nonetheless retains the capability to jump. High-speed video cameras and skin markers were used to capture three-dimensional movements of the right hind limb during jumping while ground reaction forces (GRF) were simultaneously recorded. Proximal joints were extended before distal joints during jumping, consistent with results reported in other frog species. Peak GRF ranged from 1.2 to 4.3 times body weight (similar to values recorded in jumping species), with the highest GRFs associated with both strong vertical and horizontal jumps. Peak vertical force exceeded and occurred before peak horizontal force in most trials. Thus, there does not appear to be a performance trade-off between jumping and walking in K. maculata. K. maculata exhibited a wide range of jump angles (from 1 to 50 degrees from the horizontal), with more vertical jumps apparently achieved by the animal tilting its body to a higher angle about the pelvic-femoral joint prior to take off. This motion has implications for the function and moment arms of major leg muscles, which will be investigated for all hind limb joints using inverse dynamic modelling.

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