Directing your weight: I’m sure you’ve all had the experience of sparring with a well trained opponent who doesn’t appear very heavy, but who FELT extremely heavy when he was on top of you. In Jiu jitsu your ACTUAL weight and your PERCEIVED weight are two different things. What makes you appear heavier than you are is your ability to direct a large percentage of your weight through a small percentage of your body’s surface area on to a vulnerable point of your opponents body such as the jaw or shoulder.  You will find that getting up into a tripod will allow you to direct your weight down with great precision on to a specific target that can make you feel far heavier to an opponent than your actual weight. Here Gordon Ryan uses a tripod to direct his weight down through his shoulder and make his cross face feel like it belongs to a man twice his weight. Pressure like this can have a devastating effect from top position

Directing your weight. John Danaher