[A930Rocket]

My son swims several miles a day as a year round swimmer. It's a great way to lose weight and tone up (as well as eating right).

I would say the free and fly would be the best for conditioning, but doing all four would give variety. Learning the flip turn also makes it quicker and more consistent.

That said, I swim some, but have terrible sinus allergies in the local pool and started walking more.