A short item in New Scientist reports that cats use convert only 20-38 percent of the energy they put into walking into forward motion, especially when in a stalking mode. Dogs, in comparison, are about 70 percent efficient. The work was done by Kristin Bishop, now a postdoctoral researcher at UC Davis, while studying for her Ph.D. at Brown University. Unfortunately, I can’t find a link to an original paper, and half the New Scientist story is hidden behind their subscription wall.
Bishop has shifted fields a bit in moving to UC Davis: instead of studying cat-crawls and flight in sugar gliders, she is working on the biomechanics of fish feeding with Peter Wainwright’s lab in the Section of Evolution and Ecology.