This article originally appeared in Shape.

A strong core acts as the foundation to help you crush every other workout, not to mention prevent lower back pain. Start with this beginner ab workout, then work your way up to challenge your abs in new and increasingly intense ways.

How it works: Three to five times a week, add these beginner ab workout moves, designed by Tom Seabourne, Ph.D., a personal trainer and karate expert, to your usual exercise routine. (Need some inspiration? This is what a perfectly balanced week of workouts looks like.) Once the beginner ab workout moves start to feel easy, progress to intermediate, then advanced.

What you’ll need: A yoga mat, two sturdy chairs, a resistance band, and a stability ball.