title: Inverse dynamic modelling of jumping in the red-legged running frog,Kassina maculata.
abstract: Although the red-legged running frog,Kassina maculata, is secondarily a walker/runner, it retains the capacity for multiple locomotor modes, including jumping at a wide range of angles (nearly 70 deg). Using simultaneous hind limb kinematics and single-foot ground reaction forces, we performed inverse dynamics analyses to calculate moment arms and torques about the hind limb joints during jumping at different angles inK. maculata.We show that forward thrust is generated primarily at the hip and ankle, while body elevation is primarily driven by the ankle. Steeper jumps are achieved by increased thrust at the hip and ankle and greater downward rotation of the distal limb segments. Because of its proximity to the GRF vector, knee posture appears to be important in controlling torque directions about this joint and, potentially, torque magnitudes at more distal joints. Other factors correlated with higher jump angles include increased body angle in the preparatory phase, faster joint openings and increased joint excursion, higher ventrally directed force, and greater acceleration and velocity. Finally, we demonstrate that jumping performance inK. maculatadoes not appear to be compromised by presumed adaptation to walking/running. Our results provide new insights into how frogs engage in a wide range of locomotor behaviours and the multi-functionality of anuran limbs.
authors.affiliation: Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK lporro@rvc.ac.uk.
authors.forename: Laura B
authors.identifier: 0000-0002-0546-2381
authors.initials: LB
authors.lastname: Porro
authors.affiliation: Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK.
authors.forename: Amber J
authors.initials: AJ
authors.lastname: Collings
authors.affiliation: Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK.
authors.forename: Enrico A
authors.initials: EA
authors.lastname: Eberhard
authors.affiliation: Children's Hospital Los Angeles, University of Southern California, 4650 Sunset Boulevard, Los Angeles, CA 90027, USA.
authors.forename: Kyle P
authors.initials: KP
authors.lastname: Chadwick
authors.affiliation: Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, Hatfield AL9 7TA, UK.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Richards
mesh_terms: D000054:Acceleration; D000818:Animals; D001001:Anura / Q000502:physiology*; D001696:Biomechanical Phenomena; D006614:Hindlimb / Q000502:physiology*; D007596:Joints; D008124:Locomotion / Q000502:physiology*; D008962:Models, Theoretical; D014741:Video Recording
keywords: Biomechanics; Force plate; Inverse dynamic analysis; Joint angles; Locomotion