I teach beginning readers, and the best guess I have is, they're sight words (high frequency words that don't follow phonetic rules - you just have to recognize them on sight).

That being said, I don't know what good just having these words around will do. Sure, you have to be able to recognize them, but there's no context if they're just randomly on stairs.

In them? Not at all. But by reading it and understanding probable causes and stretches/exercises that can alleviate or prevent the pain, hopefully things would get better.

That being said, consulting a doctor would still be a good idea. But having something you can do immediately, that gives you tools that could help right away, isn't bad either.

My husband had the worst sciatica, and this book helped him so much

Hot Fuzz is what I came here to suggest - it's the best ACWATNOBI (A Cop With A Theory No One Believes In) spoof/film ever.

I also think Cabin in the Woods did a great job balancing spoof (or at least meta) with actual horror.