Gravity Straps
 

I like the kettle bells too, but I recently saw something on Dr. Oz called gravity straps. They are different than resistance bands because they don't stretch out, you just use them to pull your own weight. They are hard to find, I had to buy mine online. I am looking forward to working with them because I have an old hip injury that prevents high impact workouts. They said that 20 minutes 3 times a week produces good muscle toning results.