I have to cycle 20 miles each weekend just to ride my downhill bike and cycle around 30 miles each week on my hardtail. Probably keeps me pretty fit but my knees are really really suffering now. when i get up the next morning i have to walk or cycle really gently to get them to work properly. A XC bike and 2 sets of tyres. One slick one normal so it does road and XC.

Beast yourself for say 2 mins back off till you are ready to do it again and repeat. There was a stall at the Champs last year see how far you cycle in 2 mins i was 0.79 miles so pretty go but it screws you over.

Thanks buddy, advice taken!

Greg