In reply to kevin stephens:
Hi Kevin,
I used to live in Chester, and Sarah Ramsden is an excellent teacher with a class on Mondays there (630pm - 8pm for beginners, 8pm - 930pm intermediates). She calls it "sport yoga", but its ashtanga derived. Sarah is sport science trained and uses her yoga to coach footballers (Man City mainly), so in class will talk through muscle groups, where the stretch should/shouldnt be and why certain poses are useful for sports people. Aside from linking poses with breathing, there is no additional meditation or breath work, so if that side of things is what you are after its not that type of class. Lots of rowers, runners and cyclists attend, and if I hadnt moved away I would still be there too!
She will physically adjust (with your permission) if it means you better understand the pose you are working toward.
Who ever said that ashtanga and climbing dont go has a valid point - it is not active rest. It is hard work if you apply yourself. My tuppence is that all the press up positions strengthen and balance my shoulders, which prevents a niggly impingement injury flaring up, so for me its worth it.
Lastly, once you know the moves have a look at "The Athletes Guide to Yoga" book or DVD. Written by a triathlete, with sound knowledge on when yoga is useful, plus some sport specific routines.
Hope some of that helps!