This mini trampoline is well made and comfortable to use. We have not had any ankle, knee or other pain from using it daily for a month now. I can reach my target heart rate easily with fast rhythm running in place, and alternate that with the other steps. Exercise can be as gentle as you wish. The cellerciser works as well for my wife under 120 lbs as it does for me, 180. We find it more satisfying to stay with than other stationary exercise equipment. A mini trampoline was suggested by my PT as I was unable to resume jogging without pain in my injured knee. I was easily able to increase my jumping to a level where I am getting good aerobic exercise, without trouble with the knee. I expect this will be a permanent part of our fitness program, supplementing the running, and great to use when the weather is bad.