How to avoid injuries on astro turf?

I play in a local indoor arena flag football league and I'm always getting my knees and elbows scd up really bad. I've tried the neoprene sleeves and they always ride up on contact so they really only work for the initial contact with the turf. Anybody have any suggestions on what I can do? It's getting to be ridiculous the field looks like its polka-dotted from all the blood from different players(scary in itself)