When I was younger, I swam in a near-constant state of over-training. To improve fitness, hard work is necessary but not sufficient. You also need rest - time for your body to recover and rebuild. Indeed, it’s during recovery that you get stronger. If you don’t rest enough, you don’t improve. If you’re over-trained - like I was for most of high school - increasing training load can ironically lead to decreased fitness.
My training load back then - 50K for an average week - wasn’t unusual for an elite age-group program. The problem was that I was only getting about 6-7 hours of sleep per night during the school year. (My natural sleep duration is 9 hours.) Over the course of a week, that produced a sleep debt that even a 14-hour “coma” on Saturday night couldn’t make up for.
I cut corners on my sleep because, well, I was busy. I don’t necessarily regret this choice… but I was naive about just how much it was affecting my swimming performance. When you’re that age, it easy to think you’re invincible. But over-training is very real - even for 16-year olds.
What are the symptoms of over-training? My intuitive sense is: If, for more than 30% of your training sessions, you feel crappy for most of the workout, you’re probably over-trained. For me, at times, that number was more like 60%. I didn’t understand how bad that was until years later, when I decided to respect my sleep needs and brought my “crappy workout ratio” down to 10-20%.
Dave Salo - legendary former coach of the Irvine Novaquatics and currently head coach at USC - is more scientific about it. To test for training adaptation (fitness improvements) vs. over-training, he recommends a set of 8×100 on a 4-minute interval. For the first 4, descending from 70-100% effort; for the second 4, ascending from 100-70% effort. After each swim, you take your pulse for 10 seconds, three times: immediately after finishing, then again after 30 seconds, then again after another 30 seconds.
Then, you take the sum of the three pulse measurements for each of the 8 swims, and make a chart like this:
The chart above shows three series of data, from three separate test sets. The circles show the baseline; the triangles show adaptation (improvement); and the squares show over-training.
I graduated college less than 10 years ago, but my sense is that even since then, swim coaches have become much more sophisticated about exercise physiology. One hopes these coaches are now more likely to recognize signs of over-training - leading to more athletes achieving their potential.
For more on this and other essential topics of swim training, I highly recommend Dave Salo’s book, Complete Conditioning for Swimming.