Modified plank

This core exercise is called the modified plank:
• Lie on your stomach. Raise yourself up so that you're resting on your forearms and your knees. Align your head and neck with your back, and place your shoulders directly above your elbows. Tighten your abdominal muscles.
• Create resistance by pressing your elbows and your knees toward one another. Neither should move from their positions on the floor. Hold for three deep breaths.
• Return to the start position and repeat.