Every runner wants to run the best they can without hitting "the wall". Ideally an athlete would run a race exerting a constant power at the rate that the athlete can maintain for the distance required. Cyclists can utilize a power sensor for their bike in order to monitor power output and maintain a constant value. No such power monitor exists for runners. However, Course Performance offers an alternative.

In the lab, sports physiologists monitor the rate of oxygen absorption. With the help of a scientist, and athlete can measure actual oxygen consumption, and attempt to control his/her running to keep his/her oxygen consumption constant. This method could be used to run an ideal marathon on a treadmill in the lab.

There are issues with controlling oxygen intake. The body regulates oxygen intake over a period of time. As the body expends more power, it takes a period of time before our rate of oxygen intake is increased to compensate. This can result in the body exerting more power than it produces aerobically, causing an oxygen debt. Once this oxygen debt is large enough, it takes its toll on the performance.