The Plank Walk Up
This excercise is a great way to strengthen your core and shoulders while maintaining tension throughout your body.
Here's how you do it:
Start in a plank position on your forearms
Push-up to a straight arm position using your right arm as your lead arm. Left follows.
Repeat 8-10 times on the right side and then 8-10 times with your left arm as your lead arm.
If you are a beginning start with 8 reps, and if you have been working out, start with 10 reps.