Originally Posted by
gobicycling
People don't realize that swimming takes a whole different set of muscles and aerobic endurance. I've seen folks who were fit from bicycling and or running get entirely pooped out the first time they tried to swim a lap in the pool.
Swimming is a very technical sport. A person can have muscles and endurance and still perform poorly in the pool. I can see in the swimming pool some people struggling and barely moving forward, others just glide seemingly effortlessly lap after lap.
These days it is so much easier to improve the technique with all those instructional videos on the YouTube. I have learned to swim in my school days, however, the swimming technique has evolved considerably over the years, noticeably in freestyle/crawl stroke. When I have returned to the pool a few years ago and watched online videos I have discovered the miracle of "high elbow", s-curve, rotation, the importance of relaxation, control, synchronization. My personal observation is that aerobic endurance transfers well between swimming, biking and running.