title: Exercise training enhances aerobic capacity in juvenile estuarine crocodiles (Crocodylus porosus).
abstract: Aerobic capacity (VO2max) of endothermic vertebrates is known to increase with exercise training, but this effect has not been found to-date in non-avian reptiles. We exercised juvenile estuarine crocodiles (Crocodylus porosus) to walk at 0.75-0.88 km/h on a treadmill for up to 20 min a day over 16 weeks, and compared their aerobic performance with that of unexercised crocodiles. In the exercised group, VO2max increased from 6.9 to 8.5 mLO2/kg/min (+28%), and locomotor endurance increased from 3.8 to 6.9 min (+82%). Neither VO2max nor endurance changed significantly in the sedentary group. This finding extends the exercise training effect onto another vertebrate clade, and demonstrates that ectothermic amniotes are capable of elevating their aerobic capacity in response to exercise training. We propose that differences in cardiopulmonary structure and function in non-avian reptiles may be responsible for the absence (in squamates) or presence (in crocodilians) of a strong training effect on aerobic capacity.
authors.affiliation: School of Earth and Environmental Sciences, University of Adelaide, South Australia 5005, Australia. towerkow@uci.edu
authors.forename: Tomasz
authors.initials: T
authors.lastname: Owerkowicz
authors.forename: Russell V
authors.initials: RV
authors.lastname: Baudinette
mesh_terms: D000489:Alligators and Crocodiles / Q000502:physiology*; D000818:Animals; D001481:Basal Metabolism / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D008124:Locomotion / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D053833:Wetlands
chemical_list: D002245:Carbon Dioxide