Palm Springs Half Marathon part II

OK I ran 50 minutes....the 1st 35 were almost euphoric! At 40 minutes the tightening began, by 45 minutes I thought I may have to stop there, then I thought "one more minute...by then I felt the pain was not increasing so I added another 5 minutes for the full 50....It hurt. It has been so long since I have run....Good news??? Well I was able to play tennis the next morning! Yippee!