WeightLossResourcesUK says Some people (and NASA!) think rebounding is the best exercise yet. Here's a roundup of the benefits and some comments from rebounding devotees. Possibly the Perfect Exercise! It’s fun, it’s easy, and it’s safe for almost anybody of any age… It’s quoted by NASA as “the most efficient and effective exercise yet devised by man”, and you can do it at home whilst watching TV! What is it? Rebounding!