How to do sit-ups: learn how to nail this exercise and perfect your form

Here’s how to do sit-ups: with beginner and advanced tips, variations, and common mistakes to avoid

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

Wondering how to do sit-ups? If you answered yes to that question – keep reading. It’s fair to say sit-ups have gained superstar status as one of the best workouts for your abs. Why? Not only is this humble form of exercise often introduced at a very young age, but sit-ups are among the most well-known forms of training to add to any fitness regime. Especially if you’re looking to target your rectus abdominis - otherwise known as, abdominal muscles.

Different from crunches – which are designed to isolate your upper abdominal muscles – sit-ups are great for your lower abs. You might have learned how to do sit-ups in school, but we can all fall into bad habits caused by repetitive movement patterns.

So, whether you’ve had a short break from fitness or you are just starting your exercise journey, we’ve pulled together an expert-packed list of everything you need to know about how to do sit-ups. From how to engage your core to how to perfect your form, to the most common sit-up mistakes to avoid, in addition to advanced and beginner tips. 

Or, to take your training up a notch, check out the best online personal trainer and fitness apps to nail your workout with expert advice 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 (opens in new tab) 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, sit-ups 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 (opens in new tab), 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 is an experienced health and fitness journalist and is currently Fitness and Wellbeing Editor at TechRadar, covering all things exercise and nutrition on Fit&Well's tech-focused sister site. Matt originally discovered exercise through martial arts: he holds a black belt in Karate and remains a keen runner, gym-goer, and infrequent yogi. His top fitness tip? Stretch.

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