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The one ab exercise you should stop doing — and what to do instead

A photo of a young man doing sit ups
(Image credit: Shutterstock)

Sure, you’re hoping to get the six pack of your dreams, but did you know that not all ab workouts are created equal? In fact, there’s some exercises that experts really wish you’d stop doing, and sit-ups are at the top of this list. 

We don’t need to tell you that doing hundreds of sit-ups a day won’t get you abs — how visible your abdominal muscles are actually depends on your body fat percentage (take a look at these exercises to help target belly fat, plus the cardio exercises that burn more calories than running). In addition to not being all that effective, according to Harvard Health Publications, sit-ups can be potentially damaging to the spine.  

Medical professionals explain that when you perform a sit-up, you’re pushing your curved spine into the floor, while flexing upwards. If you suffer from tight hip flexors, or sit down a lot, your hip flexors can tug against your lower back during this upward motion, creating pain or discomfort in the lower back. It’s thought to be even worse if you perform sit-ups with your hands behind your head and almost pull your body upwards. While you might not notice this initially, over time, doing endless sit-ups could lead to back pain. 

While sit-ups do target the rectus abdominal muscles, there are thought to be more cons than pros of this exercise, and, to a lesser extent, crunches. Luckily, there are plenty of other effective ab exercises out there that can be performed without flexion or pressure on the spine. As always, if you do experience any back pain when exercising, it’s a good idea to check with your doctor or physiotherapist. 

The ab exercises to do instead of sit-ups:

1. Front planks  

In order to correctly get into the plank position, start in a press-up position, with your arms slightly wider than your shoulders and your body weight resting on your hands flat against the floor, or your forearms, depending on which variation you opt for. Think about creating a straight line from your heels to the crown of your head, engaging your core. Here’s how long you need to hold a plank to get results (spoiler — its not as long as you think!)  

2. Mountain climbers  

To do a mountain climber, start in a push-up position, then as quickly as you can, pull your right knee into your chest without letting it touch the floor as you extend it back out. Then repeat with your left knee. That's one rep.  

3. Deadbugs 

Start with your back and shoulders flat and heavy on the floor. Lift your arms straight above your shoulders and your legs in table top position, your knees directly over your hips. Take a breath in and as you exhale, slowly lower and straighten your left leg and your right arm until just above the floor. As you inhale, bring them back into the starting position. Repeat on the opposite side and you've completed one rep.

4. Toe taps 

This is a classic Pilates exercise that works the rectus abdominals and the traverse abdominals. Start with your legs in a table top position. Engaging your core and keeping your knee bent, lower your right and tap your toe on the floor. Your left leg should stay in a table top position. Reverse the move and repeat on the opposite side.

5. Leg raises 

Start lying on your back, making sure your lower back stays pressed into the floor. Keeping your legs straight and pressed together, lift them up towards the ceiling and lower them back down, never putting them fully back on the floor. 

5. Bicycle kicks 

To do a bicycle kick, lie on the floor with your back flat against the ground. Place your hands next to your head and raise your shoulders off the ground. Bend your knees and draw your legs up off the ground. Bring the right knee towards your chest as you straighten your left leg, as your right knee comes up, twist your body so your left elbow touches your right knee. Repeat on the other side and make sure your legs and shoulders remain off the ground for the entire exercise. 

Jane McGuire

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 four 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.