New disability testing and evaluation software combined with an isometric strength testing machine provides a very complete and standardized means of determining disability in comparison with the norms of the general population. The software utilizes not only the machine but also the digitization of photographs taken of the subject person during each strength test. Combining the digitized photographic data, the force monitor information from the load cell of the machine and extensive anthropomorphic data the software calculates for loading of the weakest joint in the subject person and compares this loading to normative values from the general population. In this manner a percentage disability for a subject person can be calculated with reasonable assurance of the validity and reproducibility of the result. New specialized hand grips for an isometric strength testing machine are disclosed to test grip strength and torsional strength of the hand.