A Slow Worm In The Grass

I was doing the washing up just now when I spotted this slow worm wriggling frantically on the garden path and getting nowhere fast as if it couldn't get any traction on the concrete.

After I'd helped it on to the grass, it was able to move freely but it kindly hung around to pose for this blip and save you from the golf blip I had planned!

Any slow worm experts out there able to explain its behaviour?