A system for diagnosis and treatment of musculoskeletal disorders, the system comprising: a motion capture system; a computer; a display device; wherein said computer is arranged to receive data from said motion capture system; a computational pipeline of algorithms disposed on said computer; said computational pipeline being configured to: derive joint orientations, accelerations and velocities from said data received from said motion capture system; calculate joint torques, muscle forces, and joint forces from said joint orientations, accelerations and velocities; wherein said system is further arranged to: provide a computer generated image illustrating a three dimensional anatomical muscle layer disposed on an anatomical three dimensional skeleton, Characterised by the system being arranged to calculate said joint torques, muscle forces, and joint forces from said joint orientations in real time; and to visually display on said display in real time said calculated muscle forces and joint torques as real time animations of colors of the respective muscles in the three dimensional anatomical muscle layer. a motion capture system; a computer; a display device; wherein said computer is arranged to receive data from said motion capture system; a computational pipeline of algorithms disposed on said computer; said computational pipeline being configured to: derive joint orientations, accelerations and velocities from said data received from said motion capture system; calculate joint torques, muscle forces, and joint forces from said joint orientations, accelerations and velocities; wherein said system is further arranged to: provide a computer generated image illustrating a three dimensional anatomical muscle layer disposed on an anatomical three dimensional skeleton, Characterised by the system being arranged to calculate said joint torques, muscle forces, and joint forces from said joint orientations in real time; and to visually display on said display in real time said calculated muscle forces and joint torques as real time animations of colors of the respective muscles in the three dimensional anatomical muscle layer. derive joint orientations, accelerations and velocities from said data received from said motion capture system; calculate joint torques, muscle forces, and joint forces from said joint orientations, accelerations and velocities; wherein said system is further arranged to: provide a computer generated image illustrating a three dimensional anatomical muscle layer disposed on an anatomical three dimensional skeleton, Characterised by the system being arranged to calculate said joint torques, muscle forces, and joint forces from said joint orientations in real time; and to visually display on said display in real time said calculated muscle forces and joint torques as real time animations of colors of the respective muscles in the three dimensional anatomical muscle layer. provide a computer generated image illustrating a three dimensional anatomical muscle layer disposed on an anatomical three dimensional skeleton, Characterised by the system being arranged to calculate said joint torques, muscle forces, and joint forces from said joint orientations in real time; and to visually display on said display in real time said calculated muscle forces and joint torques as real time animations of colors of the respective muscles in the three dimensional anatomical muscle layer.