I have always had problems with lace up shoes keeping the laces tied.  If I did a single knot the lace would come undone quickly and if I did a double knot it would be difficult to untie the laces. The lock laces came to the rescue. They make the tie up shoes almost like a slip on shoe.  The shoes go on or off very easily and are very easy to tighten/loosen once you get them on.  I will probably use these on all my tie up shoes from now on.