ARX Adaptive Resistance Training. Precisely measure your resistance every step of the way and compare your numbers with previous workouts to see where you progressed or regressed. 3 different types of contractions you can isolate or combine with the ARX (Isometric, Concentric, Eccentric). Torso Extension, which is a safer and more basic version of a Dead Lift. Great for people that have no clue how to perform it and once you achieve proper form you can get off the machine and perform it in a classic weight lifting fashion.