Here, Crunch Fitness master trainer Matthew Harling, CPT, CSC, CES, shares beginner-friendly instructions on how to do a plank. Lie face down on a mat. Push upon your elbows and extend your legs, making sure your back is straight and your hips are level. Look directly at the ground in front of you so your neck stays in line with your spine.

Here’s how to perform a plank: Start on the ground with your elbows stacked directly under your shoulders. Straighten your legs out behind you and rest your weight on your forearms and toes. Engage your glutes and core and create tension in your entire body to maintain the position.

To perform a plank with an arm lift, follow these steps: Start in plank position. Carefully shift your weight to your right forearm (or palm). Extend your left arm straight out in front of you. Hold for three seconds while keeping your core tight. Slowly bring your arm back to starting position. Switch arms and repeat.