Butterfly Sit-Up
The butterfly sit-up is a bodyweight ab exercise where you sit up with the soles of your feet together and knees dropped out to the sides, then reach back overhead on the way down. It mainly works your abs, with your obliques helping. It needs no kit, so it suits beginners and anyone who wants a simple core exercise at home or in the gym.
Muscles worked
The Butterfly Sit-Up mainly works your abs, with your obliques helping.
Setting up
- Lie on a mat or a softer surface, not bare floor, so the base of your spine is comfortable as you roll up and down.
- Bring the soles of your feet together and let your knees fall out to the sides. Slide your heels towards your hips until your knees feel relaxed rather than forced down.
- Place your fingertips lightly behind your head with your elbows wide. Your hands are there for support only, not for pulling.
- Settle your ribs down towards your hips and take a breath in before you start.
How to do the Butterfly Sit-Up
- Breathe out and tighten your abs, as if bracing for a light poke in the stomach.
- Curl your head and shoulders up first, then keep rolling up one section of your spine at a time until you are sitting tall.
- Reach both hands forward and touch them to your feet, keeping your knees wide and your chest lifted.
- Breathe in and slowly roll back down, lowering your spine to the mat bit by bit rather than dropping.
- As your shoulders reach the floor, stretch your arms overhead and touch the floor behind your head.
- Bring your arms back to your head or reach them forward as you start the next rep, keeping the movement smooth and controlled.
Form tips
- Think about pulling your ribs towards your hips as you come up. You should feel the work low and in the middle of your stomach, not in your hands or head.
- Take about two seconds to lower. The way down is where your abs work hardest, and rushing it wastes the best part of the rep.
- Breathe out as you sit up and in as you lower. This helps you keep your stomach tight.
- Keep your feet in the same spot throughout. If they slide away from you, your starting position was too far out.
- If you can't reach your feet yet, reach as far as you can towards them. A smaller, controlled rep is better than a big, rushed one.
Common mistakes
Pulling on your head
Keep your elbows wide and fingertips light, as if holding a pair of headphones in place. If you catch yourself yanking, cross your arms over your chest for a few reps.
Swinging up with momentum
Slow the first part of the rep right down and start by curling your head and shoulders. If you need a swing to get up, reduce your reps or pause at the top for a second.
Flopping back down
Treat the lowering phase as half the exercise. Keep your abs tight and lower over about two seconds, touching the floor behind you without crashing into it.
Forcing your knees down or feet too far away
Keep your heels at a distance where your knees sit out comfortably. Forcing them flat adds nothing and makes it harder to keep the movement smooth.
Sets and reps
| Build strength | 3-4 sets of 6-10 slow reps with a two to three second lower and a short pause at the top. Rest 90 seconds. Make it harder by holding a pause at the bottom or finishing the reach overhead. |
|---|---|
| Build muscle | 3 sets of 10-15 controlled reps, resting 60-90 seconds. Stop each set when your form starts to slip, not when you are completely exhausted. |
| Fat loss and general fitness | 2-3 sets of 12-20 reps, resting 45-60 seconds, as part of a full-body workout. Core exercises build your abs but won't burn fat from your stomach specifically, so combine them with other training and daily activity. |
Pick a weight where the last rep or two of each set is hard but your form stays clean. When every set feels easy, it's time to go up.
Butterfly Sit-Up alternatives
Machine taken, or want some variety? These work the same main muscles.
Butterfly Sit-Up FAQs
What muscles do butterfly sit-ups work?
They mainly train your abs, which do the work of curling you up and controlling you back down. Your obliques help to keep the movement steady, especially with your knees wide.
Why can't I touch my feet on a butterfly sit-up?
It's common, especially when you're starting out. Move your heels a little closer to your hips and reach as far as you can, focusing on a slow, controlled curl. Your range will improve as you practise.
How many butterfly sit-ups should I do?
Most people do well with 2-4 sets of 8-15 reps. Choose a number you can complete with smooth, controlled reps and add a rep or a set over the following weeks. Stop if anything hurts and get it checked.
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