Why do this drill?
The use of the fists drill encourages the swimmer to develop an early vertical forearm and use their forearm and hand effectively as a paddle through the underwater phase of their stroke. Fists drill is a good drill to develop feel for the water as it allows the swimmer to become aware of the water against their forearm.
How to do this drill
To perform the fists drill swim with your full stroke but with closed fists. Keep your fists tightly closed but relaxed throughout the complete stroke cycle. Since you no longer have your hands to use, you will feel like you need to get a better hold of the water and you should do this by bending your elbow early in the catch phase. During the pull phase, focus on your forearm – feel the pressure of the water as you move it backwards.