Abstract: A method of training and simulating physical skills using a digital motion analyzing device that measures the necessary and sufficient information to describe uniquely a rigid body motion. The device, comprising a programmable digital signal processor and a universal accelerometer, measures the acceleration and calculates the linear velocity, the angular velocity, the orientation, and the position of a moving object, and stores and plays back the motion using audiovisual means and compares it with other pre-recorded motions. The student can choose a model and try to imitate the model with the help of audiovisual means and biofeedback means. The device is portable. It can also be connected to a computer where the motion can be further analyzed by comparing it with a database comprising many other characteristic motions. If a projectile is involved, such as in a golf swing, the trajectory of the projectile is calculated.