If the test is accurate which I highly doubt, 4.7% is extremely low, if it is however, your problem will probably be your abdominal muscles aren't developed enough, avoid high repetitions and instead hit the muscles heavy using weight plates and/or dumbells, aiming for a weight where you can manage about 8-12, try weighted crunches, hanging leg raises, reverse crunches using the weight plates and dumbells, and don't forget russian twists and oblique crunches to hit the obliques aswell.
Hope this helps.