Originally Posted by Mister Paruyr

The reason behind that is because swimming requires the usage of more muscle groups than most other sports. Also, those muscles are constantly moving.

In the water, you are also constantly moving against a resistive force, so your muscles are constantly working out.

The main idea of having a great cardio is not running in place for 30 minutes, because your body will hit a plateau and won't progress anymore. A really good cardio workout works when it trys to maximise efficiency, and to do this, you have to have variety in the exercises you do.

Originally Posted by swpthleg

The power of Aleks, his small baby and pimp hardcore dogs has granted you useful insight, my friend.

Originally Posted by wukkadb

Perfect post, repped. The only thing I could add to that list is cycling but why not wait for Cyclist to come? Haha. Great advice though. Something else you can do for cardio is bodyweight circuits. There are a bunch of things you can do such as burpees, push ups, clap push ups, sprawls, sit ups, different ab work outs, etc. Here's a good example of one:

Burpees x 15
Push ups x 15
Sit ups x 15
Burpees x 10
Push ups x 10
Sit ups x 10
Do that circuit once, rest for a minute, do it again, rest for a minute, do it again. Tell me how ya feel.

If you want the ultimate conditioning work out, try the 100 burpee or 100 snatch challenge

Originally Posted by BigAGraffy

Great circuit training right there do that three times and your going to feel it burn all the next day.