A method allowing the synchronizing collection of motion and ground reaction forces data at the start of a sporting event which are received from motion and force sensors embedded in insoles worn in the user's footwear. Furthermore, this method allows synchronization of said data with video or television transmission, and if used during, for example, during ski racing, provides information of skis' pitch, roll and heading in a 3-D space, as well as linear and angular velocity, g-forces, and the location and distribution of pressure points and ground reaction forces transferred to the user's feet in a numerical or a graphical form.