The prone (face down) bridge or plank is a great exercise if you are trying to develop the core. This exercise is unique in that it is done from a static position. There are no repetitive movements. The prone bridge strengthens the lower back, as well as several muscles in the upper body. If you are new to exercise, consider starting with a modified version of the prone bridge, then progress to a full bridge. A workout mat is recommended.
The starting position for the prone bridge is similar to the push-up, except the elbows are bent and the forearms are flat on the floor. The palms can either rest on the floor or they can be together with the fingers interlaced. Next, use your elbows and toes to hold the body up off the floor. It is important to keep your back flat, abs tight, and body completely straight. Hold this position for several seconds (between 30 and 60) and repeat. You can modify this exercise by doing it from the knees instead of the toes.
Get into the plank position. Keep abs tight and hold for 30 to 60 seconds.