What's the Name of That Book??? discussion

Sci- fi book. fighting tournament melee weapons. protagonist develops a kata of "useless" moves, I think he fights with a karambit, another character is a rich scientist with a performance drug that is trying to take top place before the army gets it from him and the substance is outlawed in the competition, one of the top 2 guys fights with a cane.

When did you read it or when was it published? Paper book, ebook, online, other? Cover art? Author male or female?

paperback, around 08-09 can't remember if it even had a cover, I was underway on a submarine and it all just blurs

musashi flex. excellent book

The Musashi Flex by Steve Perry for the link.