The Colorado Experiment was a bodybuilding experiment run by Arthur Jones using Nautilus equipment at the Colorado State University in May 1973.
It is of interest due to its claims that incredible results can be achieved with a small number of sessions using single sets of high intensity repetitions to momentary muscle failure focusing on negative or lowering multi-joint exercises. The first subject, Casey Viator, was said to have gained 63 pounds of muscle in 28 days and the second, Arthur Jones, gained 15 pounds in 22 days.
These claims are considered controversial because it was only performed with two subjects who were not "average," but regaining pre-existing muscle mass.
The results of the experiment do not appear to have been repeated in a scientific study.