If you are over the age of 35, you probably grew up being told by your coaches that in freestyle your hand should enter the water thumb and forefinger first, above your head, and pull underneath your body in an s-shape. Since then things have changed quite drastically.
Many of you reading this may be too young to know what the heck I'm talking about, but the rest of us suffer from old muscle memory from s-pull freestyle. Those affected often have what’s considered a crossover problem, usually indicated by sore shoulders at the end of a freestyle workout.
The crossover problem comes from improper hand entry, and it puts a lot of stress on the shoulders. Because we were trained to make sweeping s-pulls, our brains tell our arms to grab as much water as possible. This causes us to do a lot more work than is actually necessary. You can eliminate the crossover problem by taking the 11-train:
Imagine a straight line that divides your body in half, with two parallel lines running directly over each of your shoulders. These three parallel lines form a train track down the length of the pool. The center track contains the engine, guided by your head, while your legs power up and drive your body down the tracks. Each arm stays on its respective track, adding propulsive force to the kick. Seen from above, your arms held straight out would look like the number 11.
By jumping on and off these imaginary tracks with an s-pull, we exert more energy than we realize. That inefficiency can damage your body in the long run. When swimming freestyle, take the 11 train instead for your most efficient stroke yet.