Sounds like a good idea. It's probably applicable/sellable across more sports than rugby. Being from Canada, I could see a use for this in professional Hockey.

In my opinion, you should look into getting a patent or at the very least file a PPA (provisional patent application) which is available in the US and maybe in other countries as well. Once you are *protected* shop the idea (and a prototype) around to existing sports equipment / support garment manufacturers for a percentage royalties deal. Get them to license the idea from you.

That way you don't risk too much in manufacturing a product that may or may not sell. Put the risk on the manufacturer who already has facilities, sales, and distribution channels in place.