Put simply, running economy is a measure of how much oxygen is being consumed and how much carbon dioxide is being produced whilst running at a given speed.
The difference between running economy and running efficiency, is that running efficiency is a measure of the mechanical work completed by the working muscles, and the energy expended to do it.
If you want to know more about the physiology of running, details will be released over the next few days for the Physiology of Running Webinar on July 12.
With running economy being an important determinant of distance running performance, there number of biomechanical and physiological factors influence running economy these include metabolic adaptations within the muscle, the ability of the muscles to store and release elastic energy, and more efficient mechanics leading to less energy wasted on braking forces and excessive vertical oscillation.
If you'd like to improve your running economy, make sure you register for a technique workshop near you. If you found this article useful make sure you subscribe to receive regular articles direct to your inbox.
Conley, D. L. and G. Krahenbuhl. 1980. Running economy and distance running performance of highly trained athletes. Med. Sci. Sports Exerc.
Saunders, P. U., Pyne, D. B., Telford, R. D., and Hawley, J. A. 2004. Factors affecting running economy in trained distance runners. Sports Medicine.