Shoe Question!

[shmi85.livejournal.com]

Quick question for you crafty folk:

I painted some gym shoes a while back with acrylic paints and then I sealed them with a spray sealer. It's been working great, except that the paint is cracking near the toe where the shoe bends. I don't care too much, since they're gym shoes.

However! I have a pair of grey heels that I want to paint black. When the paint cracks along the toe bendy lines, it's going to look really awful. Does anyone have any good (inexpensive) tips for how to avoid this problem?

Thanks a ton!