Making Olympic lizards: the effects of specialised exercise training on performance

Area of Science:

• Comparative physiology
• Exercise science
• Vertebrate biology

Background:

• Exercise training effects on physiological and performance traits are well-documented in mammals.
• However, training responses in other vertebrate tetrapods remain inconsistent.
• Green anole lizards (Anolis carolinensis) serve as a model to investigate training adaptations in reptiles.

Purpose of the Study:

• To examine performance and physiological differences in green anole lizards after specialized sprint or endurance training.
• To understand the muscle plasticity and physiological adaptations in response to different exercise regimens.
• To provide insights into the phylogenetic distribution of muscle plasticity in vertebrates.

Main Methods:

• An 8-week rigorous training regimen involving sprint and endurance protocols was applied to green anole lizards.
• Performance metrics (sprint speed, endurance capacity) were assessed post-training.
• Physiological analyses included haematocrit measurements and muscle fiber cross-sectional area determination.

Main Results:

• Endurance-trained lizards exhibited significantly higher post-training endurance capacity compared to control and sprint-trained groups.
• No significant differences in sprint speed were observed among the treatment groups post-training.
• Endurance training led to increased haematocrit and larger fast glycolytic muscle fibers.
• Sprint training resulted in significantly larger slow oxidative muscle fiber areas, despite no change in maximal sprint performance.

Conclusions:

• Exercise training elicits distinct physiological and performance adaptations in lizards, with endurance training enhancing endurance capacity.
• Muscle fiber plasticity in response to training appears to be a conserved trait across vertebrates.
• Findings suggest caution when extrapolating training research from mammals to other tetrapod groups and highlight the potential for widespread muscle plasticity.