I can't seem to do a crunch without hurting my back. Every time I sit up, it feel like my spine is pressing into the floor and hurts really bad. Am I doing something wrong? Is there a better way? It seems the only way I can do a crunch without it hurting my back is on the bed. Then I end up just rolling around because my bed is really... what's the right word?... fluffy.
Should I get an exercise ball? What about those ab lounges? Are they worth it?