Bird Dog

How to do it

1. Start on all fours with your hands under your shoulders and knees under your hips.

2. Brace your midsection so your lower back stays flat, not arched or rounded.

3. Reach one arm straight forward and the opposite leg straight back at the same time, both roughly level with your torso.

4. Hold for a second, return, and switch sides. Keep your hips square to the floor throughout. If they tip, you are reaching too far.