Although not even the world's best coach would be capable of providing a written list that could guarantee success, the following 10 points are core things to remember when attempting a perfect freestyle stroke (also known as the crawl).
With luck and perhaps a little poolside advice from another swimmer or instructor, these 10 items should ensure that you have the basic freestyle stroke mechanics down pat. You may already have several of them mastered, or you may just be starting to learn how to swim. Either way, there's no better time to make technical improvements than now.
Take one tip per week and only concentrate on that specific aspect of your stroke. The next week, choose to work on another tip, but remember the one you practiced the week prior. In 10 weeks time, not only should your stroke be markedly improved, but the improvements will feel natural and require less concentration because you added them together slowly over the course of a few months.
Rather than information-overloading yourself with too many things all at once (a common problem at weekend-long swim clinics), you will have taken several months to carefully master all the different, basic elements.
1. Head Position
Body position in the water is the most important component to swimming efficiently, and the position of your head dictates the position of the rest of your body. Look forward, with your hairline cresting the surface of the water in front of you (if your hairline is receding, then make sure that your forehead is just below the surface!).
Your neck and upper-back muscles should be relaxed, and assuming that your body is parallel to the bottom of the pool (as it should be), your head should be cocked forward about 45 degrees. If you "bury" your head into your chest, it will serve as a 25-pound form of resistance. It also will alter your body position by forcing your upper body to dive down and your hips to breach.
Conversely, if you look forward too far, your face will serve as resistance and your neck and upper-back muscles will tense up, causing fatigue and discomfort.
2. Reach Forward
With each stroke, make sure you are extending your arm to its maximum length. Many swimmers place their hand in the water in front of their head and begin their underwater pull. Instead, concentrate on placing your hand in the water about 15 inches in front of you, and then reach forward an additional 6 inches by extending your arm from your shoulder.
That little movement involving your shoulder (imagine you are standing and trying to reach for a ceiling just beyond your reach) can lengthen and smooth out your stroke for maximum efficiency.
3. Body Rotation
Body rotation is somewhat related to reaching forward, in that by pivoting your body with each stroke, you facilitate your shoulders extending forward at the end of each stroke. When your right arm is fully extended in front of you (and your left is about to exit the water behind you for its recovery), your body should be pivoted right.
This means the entire right side of your body should be submerged and facing the bottom of the pool, while the entire left side of your body should be breaching toward the ceiling/sky. With the next stroke, your body pivots to the left, altering your position about 120 degrees. Picture a rotisserie chicken being pivoted on the axis of the spit, and that is how your body should rotate with each stroke.
4. "Hourglass" Pull
When you are pulling your body through the water with your arms, you want to maximize the amount of water pulled. Since the shortest distance between two points is a straight line, the last thing you want to do when swimming is pull your arm through the water in a straight line. Instead, practice an S shape (a longer way of completing each stroke), so that if you were to pull both arms together simultaneously, the resulting path would resemble an hourglass silhouette (this simultaneous silhouette should also diagram your butterfly underwater pull).
At the beginning of the stroke, the hand extends out, away from your body. Keep your elbows high. As you catch the water, curve your hand back inward toward your belly button, then out again by your hip as your hand exits the water.
5. Finish the Stroke
Even some of the world's best swimmers end up shortening their strokes when they get tired, pulling their hands out of the water prematurely at their waist area rather than by their upper thigh. As your arms complete their underwater hourglass pull, they should fully extend behind you, by your sides, so that your thumbs graze the side of your thighs below your suit-line.
Many swimmers begin bending their elbows toward the end of their stroke and pull their arms out of the water before allowing them to finish their path. By shortening their stroke, these swimmers lose efficiency while actually expending more energy because they are taking more strokes per lap (essentially spinning their wheels).
A former swimmer at Stanford University, Alex Kostich has stayed strong in the sport at the elite level even while maintaining a day job. The three-time Pan-American Games gold medalist still competes in—and wins—numerous open-water races around the world each year, as well as competing in the occasional triathlon and running race.