Technically, your abdominal muscles consist of five major muscles: (1)

Rectus Abdominis Located between the rib cage and the pelvic bone, this is more commonly referred to as the “six-pack.”External Obliques These sit on the sides of the rectus abdominis and allow your trunk to twist.Internal Obliques These also flank the rectus abdominis, but inside the hipbones, and also help with twisting motions.Transversus Abdominis These sit behind the obliques and help stabilize your trunk. They’re also sometimes called the corset muscles.Pyramidalis This small, triangle-shaped muscle sits in the pelvis and helps maintain internal abdominal pressure.

Together these muscles are responsible for your ability to bend over or curl up. (Hello, crunches.) But those muscles are just one part of your core, which refers to the muscles that are essentially the foundation of your body, allowing you to hold your body up, explains Eric Botsford, a National Strength and Conditioning Association-certified personal trainer and a frequent participant in high-level fitness competitions like the CrossFit Games and Tough Mudder events. “All movement originates in the core, so there’s an importance to prioritizing some form of core-centric exercise in your everyday routine,” he explains. Your core also includes the erector spinae muscles, which are the muscles in your spine that help stabilize you as you stand or sit up, lift something, or rotate your upper body. (2) Working all of these muscles — your abdominal muscles, as well as the muscles in your spine — together is how you get a midsection that looks more sculpted. And more important for your health and overall functioning, this stronger core improves balance, posture, and mobility, while also decreasing risk of injury and some types of chronic pain (like in your lower back). The bottom line: Stronger abs will make aging overall a little bit easier. But that doesn’t mean you need to hit your bedroom floor and crank out the crunches, Botsford says. “The biggest misconception is that you need to do sit-ups in order to train the core.” Instead, he suggests a mix of isometric exercises (static ones, such as a plank or wall sit, whereby a muscle gets stronger by stabilizing itself) and dynamic exercises. (3) And Botsford recommends focusing on moves that engage all your core muscles, not just ones that focus on the rectus abdominis. And remember: Just because you can’t see a visible six-pack doesn’t mean that you don’t have strong abdominal muscles. “Don’t be fooled by what social media defines as a strong core,” says Botsford. “There are people out there who don’t have washboard abs but can 100 percent carry more weight than that model on Instagram.” Repeat the exercises in each circuit three times to complete one workout. Rest as little as possible between moves (and no more than 90 seconds, Botsford says). Aim to finish whichever level workout you choose twice weekly — and when you’re ready to up the intensity, do it three times per week Note: If you have any injuries or medical conditions that might limit your ability to exercise, check with your doctor before starting a new workout.

Beginner Circuit

  1. Dead Bug via GIPHY Lie on back with arms extended, reaching straight from shoulders to the sky. Bend and raise knees so they form a 90-degree angle. (Shins should be parallel to the floor.) Squeeze abs and press lower back into the floor. hold this position for as long as possible up to 45 seconds, then rest for 15 seconds. Repeat two more times.
  2. Plank via GIPHY Place hands and knees on the ground, then place forearms on the ground to support your body weight. Elbows should be directly beneath your shoulders; hands can be holding one another (forearms angled in toward one another) or flat on the ground (forearms parallel to one another). Step feet back so your body forms a straight line, parallel to the floor from your shoulders to your ankles. Brace your core and hold this position for as long as possible up to 45 seconds, then rest for 15 seconds. Repeat two more times.
  3. Side Plank via GIPHY Begin in plank pose. Place right elbow directly beneath the middle of your chest facing forward, then lift left hand to your waist, stacking your left foot on top of your right (so left leg is stacked on top of right, too). Lift your left arm to the sky, keeping hips lifted and glutes squeezed. Hold for as long as possible up to 45 seconds, then rest for 15 seconds. Repeat two more times, then switch to the other side and repeat.

Intermediate Circuit

  1. V Bicycle via GIPHY Begin seated in a V position on the floor, balancing on your butt with legs extended diagonally in front of you and arms extended diagonally behind you (so your limbs form a V shape). Bring right elbow toward left knee, keeping chest open and extending right leg out long. Repeat on opposite side with left elbow coming to right knee. Do as many reps as possible while maintaining proper form, up to 20 reps.
  2. Elbow Plank Pass Through via GIPHY Return to a side plank position. Lift top arm straight to the sky. (If too difficult, modify by dropping your bottom knee to the floor with that leg pointing behind you.) Bend slightly at the waist to reach down and pass your top arm through the gap between your side and the floor. Return to your original position and repeat. Do as many reps as possible while maintaining proper form, up to 20 reps. Repeat on the other side.
  3. Side Plank Knee to Elbow via GIPHY Start in a side plank position with your right elbow on the ground supporting you, keeping hips lifted and glutes squeezed. Extend left arm overhead, then slowly bring your left knee to touch left elbow, crunching your body inward. Return to start. Do as many reps as possible while maintaining proper form, up to 20 reps. Repeat on the other side.

Advanced Circuit

  1. Hip Touches via GIPHY Begin in a plank position (forearms resting on the ground supporting your body weight) with hips slightly elevated in a piked position. Drop the left hip to the floor, return to piked hip position, and drop right hip to the floor. Continue alternating to do as many reps as possible while maintaining proper form, up to 18 reps.
  2. Squat Thrusts via GIPHY Start in a standing position with feet positioned slightly wider than your hips’ width apart. Lower butt back down into a squat position. Quickly place your hands on the floor and jump legs out into a full plank position. Jump legs back to a squat and return to standing. (If jumping is too difficult, modify by stepping back instead.) That’s one rep. Do as many reps as possible while maintaining proper form, up to 15 reps.
  3. Lateral High Knees via GIPHY Start standing. Bring left knee up towards chest and right palm to ear in a runner’s stance. Quickly switch arm and leg (as if you were jogging), and move a step to the left. Continue alternating for three steps; that’s one set. Move back the opposite way for three steps; that’s a second set. Do 12 sets total, six on each side.