Exercise Physiology - Selective Breeding Experiments With Rodents

Selective Breeding Experiments With Rodents

Rodents have been specifically bred for exercise behavior or performance in several different studies. For example, laboratory rats have been bred for high or low performance on a motorized treadmill with electrical stimulation as motivation. The high-performance line of rats also exhibits increased voluntary wheel-running behavior as compared with the low-capacity line. In an experimental evolution approach, four replicate lines of laboratory mice have been bred for high levels of voluntary exercise on wheels, while four additional control lines are maintained by breeding without regard to the amount of wheel running. These selected lines of mice also show increased endurance capacity in tests of forced endurance capacity on a motorized treadmill. However, in neither selection experiment have the precise causes of fatigue during either forced or voluntary exercise been determined.