Natural terrain constantly challenges locomotor stability. Bipedal parasagittal runners rely on proximo-distal control mechanisms and passive mechanical mechanisms to rapidly adjust to changing environments. However, it is not known how sprawled bipedal runners, like the basilisk lizard, adjust to unexpected perturbations. This study examines how basilisks navigate visible drop perturbations to elucidate the control strategies used to maintain stability. We ran four basilisk lizards along a 2.7 m long trackway with an embedded 6-d.o.f. force plate. Control trials were recorded with the force plate mounted flush to the track surface. We lowered the plate to 40% of the lizards’ limb length, relative to the track surface, for perturbation trials. We hypothesized that much like parasagittal runners, basilisks would rely on three distinct compensatory mechanisms to convert the potential energy (PE) change from the drop into fore-aft and vertical kinetic energy (KE) or to increase the total energy of the system (Ecom), as well as a fourth potential mechanism converting PE into medio-lateral KE, as a result of their sprawled limb posture. On average, lizards ran slower (T-ratio30=2.548, p = 0.0162) and with a more vertical limb posture (T-ratio28=-6.119, p < 0.0001) during the drop perturbation. As expected, vertical KE increased in drop surface trials. However, contrary to our hypothesis, the drop perturbation appeared to have little detectable effect on fore-aft and medio-lateral KE. Preliminarily, these results suggest that the sprawled limb posture may afford increased robustness to perturbations such as a sudden drop in surface height, facilitating kinematic compensations independent of significant kinetic changes. / Kinesiology
| Identifer | oai:union.ndltd.org:TEMPLE/oai:scholarshare.temple.edu:20.500.12613/4149 |
| Date | January 2016 |
| Creators | Tucker, Elizabeth Lonsdale |
| Contributors | Hsieh, Tonia, Jeka, John J., Thomas, Stephen |
| Publisher | Temple University. Libraries |
| Source Sets | Temple University |
| Language | English |
| Detected Language | English |
| Type | Thesis/Dissertation, Text |
| Format | 53 pages |
| Rights | IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available., http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | http://dx.doi.org/10.34944/dspace/4131, Theses and Dissertations |
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