Here is Dr Ron's Power Matrix 3rd Principle demonstrated on the Powertec Multi System leverage bench press.
The beauty of this type of training is that you get an intense muscular workout but without over loading the joints. You only can lift a fraction of the weight you could lift in traditional set and rep formats. As I get older I find my joints simply can't take the load they once could. You still should train heavy, but not as frequently as you did when you were younger. So these Matrix workouts are a great way to add variety to your workouts and give your joints a well needed rest.