The bird dog exercise strengthens your belly, back, hips, and shoulders.
Here's how to do it.
First get down on your hands and knees.
Now tighten your belly muscles and raise one leg off the floor, straight out behind you.
Keep your head in line with your spine, keep your body straight, and don't let one hip drop lower than the other.
Hold this for about 6 seconds, then lower your leg back down.
Repeat this with your other leg.
Do it 8 to 12 times with each leg.
Eventually, you should be able to hold your leg up for 10 to 30 seconds at a time.
Once you feel stable and secure while your leg is raised, you can try raising the opposite arm straight out in front of you at the same time.
Remember, if an exercise makes you feel worse, stop doing it.