The single leg bridge is a great exercise for strengthening your core muscles that support your lumbar spine, including your lower abdominals and lower back muscles. The single leg bridge also strengthens your hip muscles, including your glutes and hamstrings.
Get into a comfortable position on your back with both knees bent and your feet flat on the floor. You can rest your hands at your sides.
Lift one knee up toward the ceiling so that only one of your feet remains flat on the floor. Engage your lower abdominal muscles and lift your hips off the floor until your hips are high enough to form a straight line between your knee, hips, and shoulders. Hold for 5-10 seconds. Then lower your hips back to the starting position.