I did for a week or so up to a few days ago after doing my back in by the risky athletic activity of getting into the passenger seat of a mates car! Unbelievable... All I know is as my weight fully transferred to the seat I felt a painful twinge in my lower back, when I got out of the car I was aware of back pain and this got worse for a few days running until I was virtually crippled... putting socks on was about the worst bit! The lifting of one leg and placing it on the other was the difficult bit. Oddly I could still bend down no problem and riding the push bike was fine. Walking was slow, painful and involved that stance where you look like you've shit yourself! I'm glad to say I'm virtually back to normal now