I can touch my toes when I am standing up. When I am sat on the floor with my feet against the wall, toes pointing upwards, I cannot bend at all from the waist.
What muscles cause this?
I've just tried both, the only thing I can see really, is that when you are sitting on the floor, your lower half is stationary, and you are fully relying on the top half to move. When you are standing, you can also use your hips and leg muscles to stretch more.
Maybe it's flexibility more than just muscles? Your hips are more flexible than your back?
Good thought, dave. So using those tendons to pull my feet up is pulling the tendons the opposite way that is needed for bending forward.
That could be it.
As I said, Pixie, if I am sitting with feet facing forward I have no problem bending enough to hold my feet. It was when my feet are pointing up that my back seems to lock.