"Mutter all you like," Duke said. "We can work on the zen later. Here." He moved in front of her and held up his arm a few inches from where she was stretching her hands. "You can grab onto me if you start to lose your balance again, so you don't have to fall all the way out of the pose.

"Try pressing back through your raised leg like you're pushing against a wall, even while you're stretching forward. And try not to lock your knee -- that means keep just a little bit of a bend. Your knees and ankles are natural shock absorbers. When you lock them, you're putting stress on your whole body."