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Fore and hind limb dynamics during climbing jumps in goats (Capra hircus)
S84
Abstracts / Comparative Biochemistry and Physiology, Part A 150 (2008) S74–S92
A3.37 Fore and hind limb dynamics during climbing jumps in goats (Capra hircus) E. Yoo (Harvard University); D. Lee, (University of Nevada); A. Biewener (Harvard University) Goats are excellent climbers, which allows them to escape predators and reach remote food sources in their mountainous habitat. We wish to understand how multi-jointed legs are able to meet different terrain conditions and mechanical demands during vertical climbing locomotion. We studied forelimb and hindlimb function during three different climbing conditions in sub-adult male goats (N = 3, 33.6 ± 1.5 kg): a horizontal running approach jump (BXJ) onto a box platform, a horizontal approach jump (CJ1) onto a climbing wall (64° slope), and a vertical approach jump from the climbing wall up onto a horizontal ledge (CJ2). The ground reaction force (GRF) was recorded using force plates mounted in the staircase and synchronized with joint kinematics data recorded using a 3D motion-capture system and retroreflective markers attached to the center of rotation of each limb joint. Joint power (joint moment × joint angular velocity) was integrated to calculate net joint work. Time of contact (Tc) and fore-aft force (Fh) did not vary for forelimb in CJ1 and CJ2. CJ1 vertical force (Fv) was 3.8 fold greater than in CJ2 (p b 0.020). For hindlimb, there was no significant difference between CJ1 and CJ2 in fore-aft impulse and vertical impulse. External joint work at the ankle for BXJ, CJ1, and CJ2 was 0.16 Jkg− 1, 0.43 Jkg− 1, and 0.97 Jkg− 1 respectively. These differences were reflected in ankle joint excursion patterns. doi:10.1016/j.cbpa.2008.04.144
A3.38 Integration of trophic system and locomotor apparatus during predatory behaviour in Tupinambis merianae S. Montuelle (Muséum National d'Histoire Naturelle); L. Reveret (INRIA); P. Libourel (Muséum National d'Histoire Naturelle); V. Bels (Muséum National d'Histoire Naturelle) Whatever the clade and the targeted prey-item, predatory behaviour involves three phases: (i) a locomotor approach to reach strike-distance, (ii) a pause to set the entire body in strike-configuration, and (iii) the strike with predator–prey contact. Locomotor patterns and trophicdesign actions have been mainly reported separately. Our aim is to lead a study of predatory behaviour in an integrative perspective in a classical squamate predator, Tupinambis merianae (Squamata, Scleroglossa, Autarchoglossa, Anguimorpha, Varanoidea, Teiidae). Locomotor and trophic kinematics have been apprehended through 2-dimensional recording, but integrating these kinematics requires 3-dimensional reconstruction. Four synchronized high-speed-videos-cameras (200 fps) were set up with overlapping: strictly frontal view (0°), strictly lateral view (90°), and two intermediate views (30 and 60°). The digitization of a draughtboard was used for calibrating (matlab-based software) and defining a referential where the 3-D position of each of the four cameras is determined. Repetitive digitization of relevant anatomical points on each of the four views enables to recalculate the 3-D movements of structures. From this reconstruction, we extracted classical 2-D data (i.e., timing of events, vertical/horizontal displacements, gape profiles), and several 3-D data that are necessary to fully understand the body configuration (i.e., spinal column bending, head positioning including
orientation/inclination/rolling). We compared 2-D and 3-D data to provide a methodological approach for analyzing the plasticity of postures and movements according to the structural and environmental constraints. This comparison is of primary relevance to understand the success of the predatory behaviour playing a key role in the individual fitness. doi:10.1016/j.cbpa.2008.04.145
A3.39 Dynamics of suction feeding in fish: Insights from unsteady, rotationally symmetric CFD models S. Van Wassenbergh, P. Aerts (Universiteit Antwerpen) Suction feeding fish capture prey by rapidly increasing the volume of their mouth cavity. Previously, considerable insight into the dynamics of suction feeding has been gained from the expanding, hollow, truncated cone model by Muller and coworkers. This analytical model assumed that flow streamlines in front of the mouth could be quantified as a combination of a circular vortex filament and parallel stream, which was confirmed by flow visualisation studies. In the present study, the potential of such analytical models to study the hydrodynamics of suction feeding was explored by means of computational fluid dynamics (CFD). We also reevaluated some of the assumptions and results of Muller's model. Although Muller's model was in general reasonably accurate in predicting flow velocities and pressures, CFD indicated that the highest flow velocities occur further inside the mouth cavity. Our simulations also showed that, during later stages of buccal expansion, vortices with anteriorly directed flow near the intra-oral surfaces start developing. Consequently, even for simple geometries such as axisymmetrically expanding truncated cones, relatively complex flow patterns may occur. Because of this apparent complexity, computational modelling is a very promising technique for studying the biomechanical interactions between expanding heads of suction feeders and their prey. doi:10.1016/j.cbpa.2008.04.146
A3.40 How to swim the Pufferfish way: A biomechanical and CFD analysis A. Wiktorowicz Conroy (The Royal Veterinary College); M. Gordon (University of California Los Angeles) The Porcupine Pufferfish (Diodon holocanthus) is a tropical bony fish that possesses the rigid-bodied median and paired fin (MPF) swimming mode. MPF swimming generally results in steady swimming with little recoil. We detailed the swimming biomechanics and recoil movements of five individuals. The insignificant levels of recoil measured during locomotion is likely the result of morphological features and complex fin coordination. We used blade element analysis and computational fluid dynamics (CFD) to create a thrust generation model of D. holocanthus. This model will ultimately lead to an understanding of how morphology and fin beat coordination affect the swimming stability of D. holocanthus. doi:10.1016/j.cbpa.2008.04.147
Abstracts / Comparative Biochemistry and Physiology, Part A 150 (2008) S74–S92
A3.37 Fore and hind limb dynamics during climbing jumps in goats (Capra hircus) E. Yoo (Harvard University); D. Lee, (University of Nevada); A. Biewener (Harvard University) Goats are excellent climbers, which allows them to escape predators and reach remote food sources in their mountainous habitat. We wish to understand how multi-jointed legs are able to meet different terrain conditions and mechanical demands during vertical climbing locomotion. We studied forelimb and hindlimb function during three different climbing conditions in sub-adult male goats (N = 3, 33.6 ± 1.5 kg): a horizontal running approach jump (BXJ) onto a box platform, a horizontal approach jump (CJ1) onto a climbing wall (64° slope), and a vertical approach jump from the climbing wall up onto a horizontal ledge (CJ2). The ground reaction force (GRF) was recorded using force plates mounted in the staircase and synchronized with joint kinematics data recorded using a 3D motion-capture system and retroreflective markers attached to the center of rotation of each limb joint. Joint power (joint moment × joint angular velocity) was integrated to calculate net joint work. Time of contact (Tc) and fore-aft force (Fh) did not vary for forelimb in CJ1 and CJ2. CJ1 vertical force (Fv) was 3.8 fold greater than in CJ2 (p b 0.020). For hindlimb, there was no significant difference between CJ1 and CJ2 in fore-aft impulse and vertical impulse. External joint work at the ankle for BXJ, CJ1, and CJ2 was 0.16 Jkg− 1, 0.43 Jkg− 1, and 0.97 Jkg− 1 respectively. These differences were reflected in ankle joint excursion patterns. doi:10.1016/j.cbpa.2008.04.144
A3.38 Integration of trophic system and locomotor apparatus during predatory behaviour in Tupinambis merianae S. Montuelle (Muséum National d'Histoire Naturelle); L. Reveret (INRIA); P. Libourel (Muséum National d'Histoire Naturelle); V. Bels (Muséum National d'Histoire Naturelle) Whatever the clade and the targeted prey-item, predatory behaviour involves three phases: (i) a locomotor approach to reach strike-distance, (ii) a pause to set the entire body in strike-configuration, and (iii) the strike with predator–prey contact. Locomotor patterns and trophicdesign actions have been mainly reported separately. Our aim is to lead a study of predatory behaviour in an integrative perspective in a classical squamate predator, Tupinambis merianae (Squamata, Scleroglossa, Autarchoglossa, Anguimorpha, Varanoidea, Teiidae). Locomotor and trophic kinematics have been apprehended through 2-dimensional recording, but integrating these kinematics requires 3-dimensional reconstruction. Four synchronized high-speed-videos-cameras (200 fps) were set up with overlapping: strictly frontal view (0°), strictly lateral view (90°), and two intermediate views (30 and 60°). The digitization of a draughtboard was used for calibrating (matlab-based software) and defining a referential where the 3-D position of each of the four cameras is determined. Repetitive digitization of relevant anatomical points on each of the four views enables to recalculate the 3-D movements of structures. From this reconstruction, we extracted classical 2-D data (i.e., timing of events, vertical/horizontal displacements, gape profiles), and several 3-D data that are necessary to fully understand the body configuration (i.e., spinal column bending, head positioning including
orientation/inclination/rolling). We compared 2-D and 3-D data to provide a methodological approach for analyzing the plasticity of postures and movements according to the structural and environmental constraints. This comparison is of primary relevance to understand the success of the predatory behaviour playing a key role in the individual fitness. doi:10.1016/j.cbpa.2008.04.145
A3.39 Dynamics of suction feeding in fish: Insights from unsteady, rotationally symmetric CFD models S. Van Wassenbergh, P. Aerts (Universiteit Antwerpen) Suction feeding fish capture prey by rapidly increasing the volume of their mouth cavity. Previously, considerable insight into the dynamics of suction feeding has been gained from the expanding, hollow, truncated cone model by Muller and coworkers. This analytical model assumed that flow streamlines in front of the mouth could be quantified as a combination of a circular vortex filament and parallel stream, which was confirmed by flow visualisation studies. In the present study, the potential of such analytical models to study the hydrodynamics of suction feeding was explored by means of computational fluid dynamics (CFD). We also reevaluated some of the assumptions and results of Muller's model. Although Muller's model was in general reasonably accurate in predicting flow velocities and pressures, CFD indicated that the highest flow velocities occur further inside the mouth cavity. Our simulations also showed that, during later stages of buccal expansion, vortices with anteriorly directed flow near the intra-oral surfaces start developing. Consequently, even for simple geometries such as axisymmetrically expanding truncated cones, relatively complex flow patterns may occur. Because of this apparent complexity, computational modelling is a very promising technique for studying the biomechanical interactions between expanding heads of suction feeders and their prey. doi:10.1016/j.cbpa.2008.04.146
A3.40 How to swim the Pufferfish way: A biomechanical and CFD analysis A. Wiktorowicz Conroy (The Royal Veterinary College); M. Gordon (University of California Los Angeles) The Porcupine Pufferfish (Diodon holocanthus) is a tropical bony fish that possesses the rigid-bodied median and paired fin (MPF) swimming mode. MPF swimming generally results in steady swimming with little recoil. We detailed the swimming biomechanics and recoil movements of five individuals. The insignificant levels of recoil measured during locomotion is likely the result of morphological features and complex fin coordination. We used blade element analysis and computational fluid dynamics (CFD) to create a thrust generation model of D. holocanthus. This model will ultimately lead to an understanding of how morphology and fin beat coordination affect the swimming stability of D. holocanthus. doi:10.1016/j.cbpa.2008.04.147