That's one way to fix the hamstring
Did you "do" something to your hamstring ?
problems like tight hamstrings can sometimes be a result of something going wrong in your lower back
Yes physio thought so too, but in this case it more down to the xc race / 5hr run / excessive gym session / arthurs seat descent / intervals combo
pick any 3 with a bit of overstriding and cramp thrown in and you have a nice and shitty hamstring :)