Running conditioning help please
I come from a mountainbiking background and have been riding singlespeeds mostly for the last year or so. I've just started running training and while I can easily run 4miles in sub 40mins I am struggling with hyper extension of my lower leg, culminating in really doing some damage this week am virtually crippled with pain from my knee. Have had lots of conflicting advice. What would you guys suggest? Cheers.