I completed W6R2 yesterday and I don't have any problems with my thighs or knees, but am finding that I get real tightness in the lower half of my lower legs and I've no idea why. With my left leg it's below the main calf muscle at the back and on my right leg it's all the way round but again, below the big calf muscle. After 6-7 minutes of running both get so tight that it's really painful. Dreading attempting my 25 minute run tomorrow as this pain in both legs is really uncomfortable. Does anyone else suffer from this and is there anything you can do about it?