Short, Frequent Workouts vs Longer, Less Frequent Workouts
I took up triathlon this past summer. I am a lifelong cyclist, having taken up riding a bike at age 4, and have been running off and on since age 15. I'm in my late 40s now, and I finally got around to taking the advice I got at age 16 to give triathlons a try. So, I would describe myself as highly fit and knowledgeable about endurance training, but I'm woefully lacking in skill, experience and knowledge of swimming. Since I do need to keep riding the bike and running in order to remain strong in those disciplines, I have fairly limited time to hit the pool.
Based on my experience in the other sports, if I knew a swimmer/runner who wanted to take up cycling or a swimmer/cyclist who wanted to take up running, I know what I would tell them to try in order to get the most out of the time they had, but I wonder how it works with swimming. If I could take, for example, 20 minutes 3 times a week or an hour once a week to swim, which would benefit me more?