While you can buy fully-made motion capture suits, with a bit of time, money and know-how it's also possible to make your own. There are different ways of creating a mocap suit (and of utilising motion capture), but the basic principle is that in order to record movements you need to create a way for your performer's outputs (movements) to be inputted into a computer. You can do this by creating a mocap suit that has reflective markers in key positions on the body (in conjunction with special cameras), or by making a wearable mocap rig that includes inertial sensors (or IMUs) which transmit movement data directly to the computer.