Firstof all whoever said once a week on this topic, listen to him. The other thing is not to go all the way down if you can't, remeber you are supplementing your boxing skills so don't get hurt . Try to start low like another fellow suggested earlier and work your way up in weight. Three or four sets with one really low wieght warmup with a two to three minute rest break for recovery and you are done. If you feel tempted to overdue, just remeber that they call the squats the king of weight workout exercise. In other words don't push it to the limit, you still have rope skipping and roadwork to do. As with the other excercises you should do weight training on a heavy, light, medium pace with two straight days off at the end. That's three on with one day in between and the weekend off.