This exercise adds additional hamstring work to the bridge. It also creates an environment that allows the body to practice pelvic stability.
To do this exercise you will need a mat. Start by lying on your back with your knees bent and your feet planted into the ground. Let one knee float into the air so that it is right above the hip. Inhale into the belly and then exhale as you hollow your abdominals and rock your pelvis toward the belly button. Continue exhaling as you press the standing leg into the ground to lift the pelvis into the air vertebra by vertebra. At the top inhale and then exhale as you reach the top toe to the ground and lift it up again. Repeat this 3-5 times, then inhale and roll down the spine vertebra by vertebra. Repeat on the other side.
Things to think about
The hamstrings of the standing leg will work really hard during this movement. If the hamstrings happen to cramp then simply lower the pelvis and reach the cramping leg straight into the air.
To avoid cramping, initiate the pelvic rock with only the abdominals.
It is also important to keep the pelvis level, often the side of the lifted leg will drop toward the ground. Be sure to use the standing leg to hold the entire pelvis level in the air.