Did you know that swimming can build up mussel? It just depends on how approach swimming. Also before you start swimming strokes you might want to stretch so you don't tare something. There are many types of strokes. Like the crawl, breaststroke, butterfly, and the back stroke, but there are many more. The hardest swimming stroke is the butterfly, many people think the is the hardest one because it takes a certain amount of strength. the easiest stroke for many people is the breaststroke. In the Olympics there are 16 Olympic swimming events that take place in a swimming pool. My favorite one is the diving. When you are watching the summer Olympics that is when swimming is on. if you want to become a Olympic swimmer you have to at least practice 1-2 hours a day. That's all I have to say. I hope you learned how to become a Olympic swimmer.