I've just done W4R1 and I ran for the first 3minutes better than I thought I could (positive bit!). Then during the 5 min I had to have 2x 10 second breaks to walk out a cramp in my left leg. So bad I couldn't run through it. I did the next 3mins, then the cramp hit me again in the final 5min run, so 2brief walks again. I made sure each time that I ran to the end of the set, so I felt like I hadn't given up but been set-back. I'm doing stretches after runs and on days off. How do I get rid of this cramp? I can't run through it.
On a positive note my bad knee doesn't hurt at all throughout all this! (The cramp is in the left leg, bad knee is left knee, is it related/compensating etc etc!?!)