This is not how you should ever bend to clean anything!!!!! I recently had quite the experience scrubbing my shower after letting my kids paint the bathtub with a water-soluble paint I mistakenly thought was washable paint. I had to do a lot of work to get this green paint off of my kids and my shower bathtub.
When scrubbing a tub, sit whenever possible and always bend with your knees. You may even want to place a soft folded towel on the floor and kneel down. Here are the images of how you should clean the tub.
I even look a lot happier. Happy ergonomic mommy! The moral of this story: check the labels closely before you buy the wrong paint. LOL At least my bathtub is really clean now.