One question we are frequently asked is: How do I know when my swimming technique is “good enough?”
Many swimmers get to the point where they know that their technique is pretty good. Naked eye observation and even an underwater video by a coach may confirm the swimmer’s personal assessment. But, is this a reason to stop working on technique?
Measurement of the active drag coefficient (Cd) is the only way to really determine if a swimmer’s technique is “good enough.” Most swimmers who “look good” have a Cd that is below 1.0, maybe even as low as .8. However, proportionally bigger improvements in swimming speed occur as the Cd drops below .8. So, even if your technique is “really good,” you can still swim substantially faster by continuing to improve technique.
By the way, swimmers with a Cd = .7 (or lower) are rare, and (because of limitations in strength or cardiopulmonary function) they are not necessarily the fastest!