A shoe to create a problem not correct one. If you look at the picture posted on their website of the woman running gravitydefyer.com/
you will note she is running with absolutely faulty running mechanics. You never want to land on your heel with you knee locked and your center of mass behind your foot strike. Doing that will cause major injuries over time. Adding the springs to the heel of the shoe do nothing to correct that problem or mitigate it since landing on with a heel first foot strike is faulty body mechanics.
It is called WORK-ing out for a reason.
I said getting fit was simple, I did not say it was easy.
Cardio burns calories, strength work burns fat.
Eat well to lose weight, exercise to get fit
You can not build a six pack using twelve packs
Often when we seek a magic bullet for fitness we end up shooting ourselves in the foot.
"I think calories are little germs in food that all moms are afraid of" Dennis the Menace