Had a game at Bodington Hall for my Uni accommodation team. The pitch we were due to play on was a disgrace so we warmed up on the pitch next to it which was not being used for a match. Someone crossed the ball in, I headed it in.. seemed a simple warm-up. Except as the pitch wasn't being used for football match that day, the concrete blocks placed infront of the goal hadn't been involved. Eyes planted on the ball, running full-pelt, straight into a knee-high concrete block causing me to swandive over it. Was in absolute agony, got bandaged up. Just took the dirty bandage off so I could put the clean one on, and my knees swollen up like a balloon with a chunk of it missing. Lovely. Absolute agony.
I've seen the blocks you mean.. I live in Headingley, so regularly go up past those pitches. Having seen the size of them, I can only sympathise!