I'd have to say it is correct to say swimming is a harder workout if done correctly. You have to make the turns and do the strokes right and there is always room for improvement in what you are doing strokewise. Try a IM: butterfly, back, breast, free and you'll see if you keep going and do all the turns right (the back is a backhand touch, not the flip turn, ect.) That's much harder than running. Do a backstroke, say a 200, with the flip turns, counting your strokes in from the flag. You have to figure out where you make the blind turn onto your stomach and then do the flip and come back up in stroke on your back ... Stay in the correct breast stroke. Come up and make a full blast freestyle turn ... Do the correct backstroke start. Hell, the free start off the blocks takes a lot of coordination ... Oh, and the breaststroke legal start off the blocks is hard as hell to learn.
And yes, if you are rehabbing, start slow. You may just want to walk in the water to start, depending on the injury. That itself is a tremendous workout.
This post was edited on 2/27 at 7:56 am