Filthy day

Today's WoD was the Filthy Fifty. I did well on many of the items, but really struggled with the knees to elbows. Then I had a major calf cramp in my L leg. I was unable to complete double unders "aargh". I subbed in 150 R leg only singles. I finished in 31:09. Not a bad time, but i need to not break up sets as much on the next time through.