Nope, not selling pills or anything, but I thought I'd share one of the stories here in Taiwan. Recently, 2 TKD'ers won gold metals at the Olympics, and so a lot of people started having Olympic dreams. One of my friends wanted to train, and so he went to a famous trainer.. The trainer's response: "I'll train you for free, if you can jump rope for 20 minutes, none stop, not messing up once." My friend took his challenge, and failed. He said he's done running a few miles, recently out of the Military etc, but he said 20 minutes none stop of jump roping kicked his ass like he never imagined. He said it was the ultimate cardio. Now I jump rope (like 3 minutes) and it kicks my ass. I can't imagine going 20 minutes. The trainer said, "150-180 rotations a minute, 20 minutes, you hit that, and you will never have to worry about cardio." A jump rope cost me about $5, some cheaper, some more expensive. But under $10 easily. Get the ones with the larger handles. The added benefit is much better timing.. also, you don't need a lot of space. Anyplace will work, and it's a great warmup too. Also, the risk of injury is minimal, and if you want to work on good explosiveness (as jump roping is actually a form of plyometrics) you can go 5 rotations, and then a double, 5 rotations, and then a double. Crossovers, backwards, single foot, etc... I sometimes go "double, left foot, right foot" and repeat. The variations are endless, so you won't get bored. I thought I'd share, since most seem to have difficult cardio programs. It need not be that difficult people, to get good cardio. And please, save me the "I did jump ropes in the 3rd grade, it wasn't hard". Because anybody who says the jump rope isn't difficult, is lying. Hope this helps someone in their quest for better cardio.