Forget crunches — these four ab exercises blast your entire core

a photo of a woman doing an ab toe touch outside
(Image credit: Getty/Westend61)

When it comes to working your core, not all abdominal exercises are created equal. In fact, there’s some exercises that experts really wish you’d stop doing, and sit-ups and crunches are at the top of this list. According to Harvard Health Publications, sit-ups can be potentially damaging to the back, as you’re pushing your curved spine into the floor, while flexing upward.

But what should you do instead? Fitness trainer Courteney Fisher has shared an intermediate ab circuit that works your entire mid-section in just four exercises. There are five main abdominal muscles you should aim to target when working your core: the internal and external oblique muscles, the rectus abdominus, transversus abdominis, and the pyramidalis. It’s also important to work on the erector spinae muscles, and the pelvic floor muscles. 

A reminder that a strong core is about far more than just a flat stomach. Core strength and stability are important to overall fitness, and strengthening your core can help you run faster, lift heavier, and walk with a better posture. 

If visible ab muscles are your goal, unfortunately, no amount of ab exercises will make a difference if your body fat percentage is too high. Here’s how to calculate your body fat percentage, and why it matters. 

No equipment ab burner workout 

The workout consists of four different exercises that you complete two to three rounds of. Fisher recommends resting for 1 minute in between rounds, so you can really push yourself for the number of reps. 

As a reminder, if you’re new to exercise or you’re returning to exercise following an injury, it’s a good idea to check your form with a personal trainer before adding reps. Doing ab exercises with incorrect form can put you at risk of injury. 

Tuck ins: 20 reps

  • To do a tuck in, or ab tuck, start in a seated position, with your legs out straight in front of you.
  • Place your arms by your sides, with your hands facing toward your feet.
  • Lean your bodyweight back until you can feel your abs working.
  • Engaging your core, raise your bodyweight up and at the same time, bring your knees in toward your chest.
  • Move back to your starting position. That’s one rep.

Opposite hand to toe touch: 10 reps per side, 20 reps in total

  • Start by lying on your back, with your arms and legs outstretched.
  • Engage your core and crunch your right hand up, at the same time, lift your left leg to the ceiling.
  • Reach your hand to your foot — it doesn’t matter if they don’t touch.
  • Extend back to your starting position, that’s one rep. Repeat on the opposite side.
  • Make sure you keep your lower back pressed into the ground for this exercise to avoid arching your back.

Hollow body hold: 30 seconds

  • Start by lying on your back, with your arms and legs outstretched.
  • Raise your arms, head and neck off the ground, and at the same time, raise your legs a few inches off the mat.
  • Squeeze your core and hold here.
  • Keep your eye gaze toward your feet — if you feel too much pressure on your neck, lower it back to the mat, or support your neck lightly with one hand.

Plank rainbows: 20 reps

  • To do a plank rainbow, or a plank hip dip, start in a plank position on your forearms. Think about creating a straight line from your heels to the crown of your head. Engage your core — think about sucking your belly button in towards your spine.
  • Twisting from your core, lower one hip down toward the mat, then the other. Keep alternating from side to side.
  • Remember the movement should come from your obliques, not your legs — keep thinking about moving from your core throughout.

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Jane McGuire
Fitness editor

Jane McGuire is Tom's Guide's Fitness editor, which means she looks after everything fitness related - from running gear to yoga mats. An avid runner, Jane has tested and reviewed fitness products for the past five years, so knows what to look for when finding a good running watch or a pair of shorts with pockets big enough for your smartphone. When she's not pounding the pavements, you'll find Jane striding round the Surrey Hills, taking far too many photos of her puppy.