Once you learn front crawl of freestyle and have a good grasp of the stroke, there are a number of things you can do to help improve your stroke, even without formal instruction. These are called stroke drills. I’m going to go over some of the more popular drills for the front crawl, describing them and explaining how to do them and how they can improve your stroke.
1. Catch-up Drill.
The ketchup drill is very simple. You swim front crawl but instead of stroking constantly like you are used to, you hold one hand in front of you while the other recovers. Once your hands touch, you can begin stroking with the other side. This drill is a very common one used by competitive swimmers. The idea of the drill is to make you slow down your stroke. It helps prevent wind milling (doing the arms super fast) and helps increase the potential to roll as you stroke. Slowing down the front crawl stoke can be important, you are not going to go as far as fast if you have a sloppy, fast stroke, the key is to pull the water the right way and to make each stroke slower and more powerful.
2. Hands as Fists
This drill goes along with making each stroke as effective and powerful as possible. What you do is simply make your hands into fists and swim with them like that. With out your palm to pull the water, you will either go significantly slower and have to work a lot more or, you will do what the drill is designed to do, which is to make you keep your elbow up and use your forearms as your paddle, rather then your hands. One of the most common mistakes in front crawl is dropping the elbow during the stroke eliminating all the potential power you can have from your forearm pulling water, and this drill can help you fix your problem.
3. Finger Tip Drag
This drill sounds just like its name, during your stroke recovery, you drag your fingertips along the surface of the water. This drill is designed to help you learn to keep your elbow up during the stroke. When your fingertips drag along the surface, your elbow will naturally sit higher then it would normally, which means that it is already higher when you begin the pull, assisting is getting all the pull you can from your forearms during the stroke.
4. One-arm Stroke
This drill is also just like it sounds, you swim the stroke with only one arm. Keep one arm in the streamline position and use one arm to do the freestyle stroke. This drill is designed to help you learn the roll that goes along with swimming freestyle.
5. Counting Drill
With this drill you count either seconds or kicks right before your recovery for the stroke. You do your pull as normal and with your pulling hand at your side and the other hand in the streamline position with your body sideways in the water you count out three seconds or ten kicks before doing your stroke recovery, then do the other side.
All these drills are designed to help you swim the freestyle properly and, when it is swam correct, you will also be faster. The key to swimming freestyle is to remember to roll your body, because your side has less space for water to move around then your stomach, which makes you on whole, more streamlined and more aerodynamic. The other point is to remember to always use everything you have to pull the water during your stroke, including your forearms and not just the palm of your hands.
Remember that to become a good swimmer you need to practice, and these drills, along with the knowledge of what you need to do to make your stroke match what the ideal front crawl should look like.