This is an excerpt from Janet Evans' Total Swimming by Janet Evans.
Simple Workout Logs
For some swimmers, a simple log book is sufficient, whereas others like to go into much more detail. In general, the more information that's recorded, the easier it is to analyze past workouts and current progress. For some, the time it takes to remember and write down the details is not worth the effort. Their goals are more process oriented than outcome oriented, and studying which weeks were good and which were not is not important to them. For others, though, especially competitors, knowing how they felt during a particular workout or noticing a pattern of especially good or bad workouts can be extremely helpful in preparing for the next race or season. In fact, log books usually aren't optional when you swim on a team, and they become more necessary as the competition gets better. The usefulness of a log book is not restricted to swimmers. Coaches also use log books frequently, studying how an athlete performed in past workouts before writing future workouts. Details of interval, total distance, times, and athlete comments about workouts are invaluable in planning for the next season. For those groups, and for those who find statistics and details fascinating, a more detailed log is advantageous. Here's an example:
I can't emphasize enough how important it is to keep a log book. It might seem hard enough to remember a workout at the pool, much less the times for each lap, and it might be next to impossible at first. With experience, paying attention to details becomes second nature, and each week more and more details stick with you. Recording the workout while still at the pool will help you get the details down before they're pushed out of your mind by other facts and information. The process itself is therapeutic and motivating. Inspiration comes not only from flipping back through the pages to see how much faster you now swim or how substantial the gradual increase in total distance has become but also from simply wanting to record a positive workout.
I encourage swimmers to gain an appreciation for the rate at which progress takes place. A lack of understanding can bring frustration and dejection if expectations are unreasonable. Frustration and dejection too often are followed by skipping workouts here and there or quitting the sport altogether, so avoiding the mistake of expecting too much too soon will do wonders for your improvement in your swimming and fitness level. There's no infomercial claiming that swimming guarantees the loss of 10 pounds in 10 days or your money back. Results come gradually, and what results you get depends heavily on how long you've been swimming, how frequently you swim, and how hard you work in the pool.
This is an excerpt from Janet Evans' Total Swimming.