Strength Profile is a trade name first utilized by Tom Purvis in January of 1999. It represents the collective findings discovered via a procedure utilizing proprietary equipment for analyzing, measuring, and graphically representing human torque in specific activities. Currently there are four general categories: L-H-L (formerly Single Joint A), H-L (formerly Single Joint B and Trunk), Load Line Specific Multiple Joint Extending, and Load Line Specific Multiple Joint Flexion.