The Drill: To begin, stand upright on a flat surface, feet about 4-6 inches apart. Drop your arms by your side and mentally mark where your thumbs naturally line up with each thigh. Once swimming freestyle, you want to lightly drag your thumb across this spot during the underwater pull-through. This will insure that your arm is extending behind you (refer to swimmer in figure 2). Very simply, this drill taps into your muscle memory. You want to get used to pulling all the way through extending the arm behind you.