I posted about cardio recently and there were some nice suggestions about doing a HIIT type thing rather than just trog along on the treadmill for 40 minutes. So a couple of days ago I dusted off my skipping rope and did just over 30 minutes; skipping for 3 minutes, resting for one, then skipping for another 3 and so on. It was nice, I worked up a sweat and my arms felt tired but I'm wondering if this is a good way to jump rope. Before moving to Tokyo I used to train at a boxing gym and everyone there did jump rope in 3 minute intervals as its the length of a round. Does anyone have any suggestions for alternatives and improvements? I would like to continue with it because its something I can do in the parking lot behind my house, I don't have to get back on the train, and its also free. This city doesn't lend itself well to outside type stuff like sprints, let alone sled dragging.