I have been rebounding off and on since the 1970's. My last purchase was a spring rebounder and I started noticing my back would hurt after I finished only 10 min. I'm getting older and realized it was probably too hard a bounce for me. So i started researching and found the bellicon and I love it. I can really feel the difference and love the bounce and the availability of the videos so I don't get bored. My core strength is improving so much I even hit a 200 yard drive at my age of 69; I've never done that before and the bellicon is the only thing I have been doing that is different. So glad I bought it and am enjoying it immensely.