Abstract: A biomechanical system for testing a coupled joint is provided. The coupled joint has a fixed first end and a moving second end within the testing system. The testing system includes a servo actuation system operatively connected to the moving end. The system is able to impart at least four degrees of freedom to the moving end of the coupled joint. The testing system also includes a first force sensor disposed between the servo actuation system and the moving end of the coupled joint for sensing applied load, and a second force sensor disposed at the fixed end of the coupled joint for sensing transmitted load. The system also includes a controller for selectively directing input signals to the servo actuation system in order to apply selected forces and/or motions to the moving end of the coupled joint. The coupled joint may be a cervical spine specimen.