Swimming is fantastic. It's a great way of working on your cardio whilst allowing you to rest your joints. If you've had an injury it will be a great for rehab.
It's a useful skill to have and train if for no other reason that it can save your life. I was on a float trip in Missouri and got caught in a current that I had to swim against without a life jacket (dumb decision). I had crossed the river to jump off of a small cliff, and the current was against me on my way back. It was a nail biting experience for me, and I'm thankful that I didn't drown. I made it back to the shore I came from after a grinding swim, and I was basically immobilized that night from the pain in my muscles.
A heart rate monitor is the key to cardio. So many things can *feel* hard -- find something that let's you do HIIT / sprint-intensity-training -- 30s intervals above 85% Max HR -- rest to
Swimming is great. Period. But, the BEST conditioning tool is an Echo bike. Easy to sell if you have to move. Low impact. Push and pull upper body that can be done separately. Allows MUSCLE GUYS to CRUSH the littles! ALLOWS FOR AGGRESSION!
