A condition of isoplasticity is defined for a beam as the development of plastic strains simultaneously at all points along the profile fibers. Two conditions must be satisfied simultaneously, one on the profile shape, and one on the mass distribution. It appears that the second condition can only be approximately satisfied if there is a relatively large mass concentration at the tip. Preliminary experiments using a massive striking force on a statically constant stress cantilever indicate that a condition of isoplasticity may be approached.