Hi, Some one on here suggested the dynoband, sorry cannot remember where I saw it, been all over. They had a link for e-bay and it cost about 10.00. Another member had got one and was raving about it as it is simple to use and they are seeing results.
Sorry to be so vague, I will look around and try find it for more info for you. Hopefully they will see this thread and you will get it all first hand.
Good luck