Like physical strength, swimmers fall into three distinct categories when it comes to flexibility: super flexible, stiff as a board, or somewhere in the middle. Most fall into the latter group. Unfortunately, limited flexibility and mobility make it difficult to master essential swimming skills, maximize propulsion, and reduce the drag within each of the strokes. For example, a lack of chest, shoulder, and lower back flexibility will limit the chest-pressing action in the butterfly, resulting in a weaker pull and kick. Poor mobility in the shoulder joints will result in a later and weaker catch in the backstroke pull. The inability to evert the feet in the breaststroke will severely limit kicking propulsion and speed potential. And a lack of flexibility in the ankles will reduce freestyle kicking propulsion while increasing the amount of drag. Dedicating fifteen minutes a day to stretch out the tightest areas of your body is an excellent first step to gaining greater flexibility. Attending yoga or pilates sessions two to three times per week is even better.
Recommended stretches for each stroke can be found in my book The Swimming Triangle. I also created a one-of-a-kind yoga video for swimmers. Both of these performance-enhancing resources are available here.