I have this problem, especially if I try to walk on an uneven surface. When in better shape, I never had a problem with rocky uneven surfaces but I do now. The yard for this building is a surface I need to cross sometimes (to move plants off the patio if work on the building is being done), and every time it's been a problem. The surface is muddy, uneven, and rocky, with exposed tree roots, pine cones, and even sprinkler heads included. My feet feel as if they are about to collapse at any minute.