The Colorado Experiment was a bodybuilding

Bodybuilding

Bodybuilding is a form of body modification involving intensive muscle hypertrophy. An individual who engages in this activity is referred to as a bodybuilder. In competitive and professional bodybuilding, bodybuilders display their physiques to a panel of judges, who assign points based on their...

 experiment run by Arthur Jones

Arthur Jones (inventor)

Arthur Allen Jones was the founder of Nautilus, Inc. and MedX, Inc. and the inventor of the Nautilus exercise machines, including the Nautilus pullover, which was first sold in 1970...

 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

Casey Viator

Casey Viator was the youngest ever AAU Mr. America - gaining the title at the age of 19 in 1971....

, 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.