Maintaining a stable core in freestyle is an important part of a good freestyle. This standard drill is a good one to remember to help accomplish this. Why do it: Freestyle is faster when you rotate through a solid tube in the water, rather than squiggle down the pool. This drill requires the swimmer to tighten the abs a bit to maintain the straight line through the entire body. How to do it: 1) Put on a pull buoy at the ankles, not between the thighs as typical. 2) Push off and start swimming. 3) Hold the pull-buoy tight between the ankels by squeezing the legs together. 4) Keep the hips at the surface by tightening the abs. How to do it really well (the fine points): Limit the side to side movement of the legs while you're swimming. Taller swimmers will move a bit more than swimmers who are more vertically challeneged simply because of the longer line. Holding the pull-buoy in for longer swims will also show you another benefit of working the groin and inner parts of your legs. Less