I voted spinning, because it is a great workout and the class environment is typically very motivational. The only bad thing is when you start going, your butt gets so sore from the seats. I highly recommender bike shorts or getting a cushioned seat cover. I also like the elliptical trainer because it is so easy on your joints.
If you live where it snows - do cross country skiing. It has become one of my favorite ways to exercise right now!! It is supposedly one of the best workouts. I did it two days in a row - and I feel so much muscle already. It truly is sooo much fun and such a great workout.
I voted kickboxing, the kind with the heavy bags and you get to actually wrap your wrists and wear gloves. It is so stress-relieving, I just imagine the person causing stress in my life and beat the crap out of the bag
I like the ellipticals. I feel like I'm still working hard and you can work different muscle groups by going backwards, but I don't think it's as hard on your body as your feet pounding on the treadmill.
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Bad taste is like a nice dash of paprika. We all could use more of it. It's no taste I'm against. -Diana Vreeland