Turn your finger tips toward your feet and place your feet hip-width apart, pushing your hips up to the ceiling as high as they'll comfortably go. Make sure your head does not fall back, rather keep your eyes focused on your thighs in front of you.
In this position, bend your elbows and then straighten them back up and drop your seat to the ground, then push it back up to the bridge.
Alternate between the two moves. You will find you're working the upper back part of the arm known as triceps and then targeting the hips, thighs and glutes, all while stretching the front of your chest.
And if you want, you can try the moves on a sturdy bench first.
You can also do a sequence of eight tricep-dips while holding the bridge, then eight lower body dips to vary the move.
If you want to work really hard, try doing both together, which is a total-body workout.