How to do sit ups: Beginner and advanced tips, variations and common mistakes

Work your abs and hips with this very simple move: Here's how to do sit ups with good form

Woman doing sit-ups in a studio
(Image credit: Getty Images)

The sit-up is one of the best-known, most-often performed abdominal exercises around the world. Often introduced at a young age, sit-ups are a classic exercise most of us have done before, and still one of the best workouts for abscertainly the most popular. 

It’s different to the crunch, which is a much smaller movement, designed to work your upper abdominal muscles, but it falls into the same family of simple abs exercises you’ll have likely learned about in PE or gym class. 

However, like with any exercise, we can fall into bad habits reinforced by repetitive movement patterns. If you're just coming back into fitness after a long time away, or even if you're just beginning your fitness journey, you might need some new guidance on how to engage your abs. That's what this article is about: ensuring we've got the correct form so you can start developing core strength. Even experienced fitness fans should scroll through, check if they've been performing the move to its fullest potential, and discover new variations to hit your core several different ways. 

If you want to get more advanced with it, consider looking into some of the best online personal trainer and fitness apps, which can offer some expert guidance from afar.

Why do sit-ups?

The classic sit up can help in muscular development that contributes to maintaining muscle well into old age. A 2016 study published in Interventional Medicine and Applied Science showed older women with the ability to perform more sit-ups suffered less age-related muscular atrophy, known as sarcopenia, helping them to stay mobile and live longer.

In addition to providing a longer life, situps help athletes and amateur sportspeople alike. A good foundation in sit ups will provide a stronger core, working the rectus abdominis, transverse abdominis, and obliques muscle groups.

Woman doing sit ups helped by a male PT

(Image credit: iStock)

If you exercise regularly or play any kind of sport, your body's "trunk" will be twisting and turning, whether carving a wave while surfing or pivoting to kick a football. 

But have we been doing it correctly? Some critics claim sit ups are bad for your hip flexors and lower back, which sometimes take the strain of the move instead of our core. In order to avoid this, we need to learn (or in some cases, re-learn) how to do a sit up with proper form. 

How to do sit ups modified for beginners

Demonstrating a sit-up

(Image credit: Future)

Getting the sit up right does require excellent core strength, so beginners should start with the modified sit up. It’s a great alternative to the classic sit-up for those starting out on the road to fitness, or anyone who hasn’t built up their core strength and flexibility. 

Remember to keep your feet grounded throughout and your legs firmly together. The movement should come from your core.

  • Lie flat on your back with legs together, bent at the knees, and feet flat on the floor. 
  • Place your hands on your shoulders and raise your elbows, so your arms are crossed in front of your body. 
  • Raise your upper body until you’re sat upright. Lower yourself back to the start position.

How to do sit ups

Man demonstrating a sit up

(Image credit: Future)

If you’ve mastered the modified beginner sit ups, it’s time to try the regular version. Sit ups should be smooth, not awkward, with correct form and technique applied throughout. 

Take your time to begin with – it’s better to do it slowly, with correct technique, than quickly with poor technique.

  • Lie flat on your back with your fingertips behind your head, your knees bent, your legs together and your feet flat on the floor. Your elbows should be in line with your ears, or just below.
  • Raise your upper body until you’re sat upright, or as close as you can get. As you do the exercise, you should feel your abs tighten.
  • Don’t push or pull your head forward while performing the sit-up – your hands and arms should remain still throughout.

How to do sit ups: Common sit up mistakes

Woman demonstrating a v-up

The v-up is a more dynamic variation on the standard sit up

(Image credit: iStock)

Sit ups can be a tricky thing. The traditional sit up can place a lot of pressure on the lower back if you perform the move on a hard surface, as the floor places pressure on the spine as it curves. 

If you do find you're suffering from lower back pain. don't continue to perform sit ups in spite of this, as this could increase your chances of injury. Instead, make sure your exercise programme incorporates moves that tone your core without putting pressure on the spine, such as planks. 

If you do suffer from lower back pain and want to give sit ups a try, consider performing crunches on a stability or swiss ball. According to the American Council of Exercise, a swiss ball supports the curvature of your spine, allowing for a full range of motion while avoiding undue pressure on your lower back.  

Whether you're doing sit ups on a stability ball or on the floor, always focus on form over speed. Lowering your body slowly adds an extra dimension of core strength to the workout. 

The most common sit-up mistake

Think those sit-ups are going to give you six-pack abs? Not if you’ve been doing them wrong. The most common mistake people make is sitting all the way up. Remember the focus should be on how your abs feel, not necessarily on how far you sit up. It’s all about engagement, and if you sit far enough up that you feel as though you’re “resting”, you’re not giving your abs their due.  

When you do a crunch, you only need to do little pulses, crunching your mid section and releasing, over and over. Sit-ups are very much the same – don’t sit up all the way to your knees. You’ll feel those muscles working a lot harder and can probably cut the number you’re doing in half.

Variation: V-up

Man demonstrating a V up sit-up

(Image credit: Future)

The V-up adds arm movement for a greater workout. If you’re bored of regular sit-ups, this is an excellent alternative. The V-up is so-called because in the upright position, your body should make a ‘V’ shape.

  • Lie flat on your back with arms stretched out behind your head, palms facing upwards. 
  • Simultaneously raise your arms, legs and torso, as if you are trying to touch your toes. The movement should come from your trunk. 
  • Go back to the starting position and begin the next repetition straight away.

Variation: frog leg sit-up

Frog leg sit-ups are a good variation on classic sit-ups

(Image credit: Future)

A frog leg sit-up involves sitting upright as per a classic sit-up, but with your knees bent and splayed out towards the floor.

  • Lie flat on the floor with your arms overhead. 
  • Feet should be together and close to your groin area, with knees spread wide.
  • Using your ab muscles, bring your arms forward and pull yourself up to a seated position. 
  • Return to lying and repeat.

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Matt Evans
Matt Evans

Matt Evans is an experienced health and fitness journalist and Channel Editor at Fit&Well. He's previously written for titles like Men's Health and Red Bull, and covers all things exercise and nutrition on the Fit&Well website. 

Matt originally discovered exercise through martial arts: he holds a black belt in Karate and remains a keen kickboxer and runner. His top fitness tip? Stretch.