The Dead Bug: A Core Exercise That Teaches Control

The dead bug is a floor exercise where you lie on your back, arms up and knees bent over your hips, then slowly lower the opposite arm and leg while keeping your lower back and ribcage still. Its job is not to tire your abs out. It teaches your trunk to resist arching while your arms and legs move, which is the same skill you need under a barbell, carrying shopping or lifting a child out of a car seat. Done well, it is slow, quiet and harder than it looks. Done badly, it is a lot of limb-waving that trains very little.

What the dead bug actually trains

Coaches call the dead bug an “anti-extension” exercise. As your arm and leg lower away from you, their weight tries to pull your lower back into an arch and your ribs up and open. Your abdominal wall works to stop that happening. The movement is in your shoulders and hips; the trunk stays still.

That matters because a great deal of everyday strength work depends on the same pattern: limbs moving, spine staying put. A press overhead, a deadlift lockout, a carry, a sprint on the air bike. The dead bug lets you practise it lying down, with no load and nothing to fall over, which is why I use it so often with people returning to training or learning to lift.

It also teaches you to breathe while keeping tension, which is harder than it sounds and something many people cannot do at first.

How to do a dead bug, step by step

1. Lie on your back on a mat. Knees bent, feet flat to start.
2. Set your ribs and pelvis. Breathe out fully through your mouth, as if fogging a mirror. Feel your lower ribs drop down towards your hips. Your lower back will settle towards the floor. You do not need to crush it flat, just remove the large arch.
3. Lift into position. Raise your arms so your hands point at the ceiling, directly above your shoulders. Lift your legs so your knees are over your hips, bent at roughly 90 degrees. This is the start position.
4. Breathe in through your nose without letting your ribs flare up.
5. Lower the opposite arm and leg. Reach your right arm back overhead and extend your left leg out long, heel a few centimetres above the floor. Take two to three seconds. Breathe out as you go.
6. Stop where you can still hold position. If your lower back starts to lift or your ribs pop up, that is your range for now. Go no further.
7. Return slowly to the start, then switch sides.

Start with 2 or 3 sets of 5 to 8 reps per side. Rest 45 to 60 seconds. It should feel like steady, deep work in the front of your trunk, not a burn in your hip flexors or neck.

The faults I see most often

Fault	What it looks like	Fix
Back arching	A gap opens under your lower back as the leg lowers	Shorten the range. Keep the knee bent as you lower the leg.
Rib flare	Ribs lift as the arm goes overhead	Exhale longer on the way down. Only reach as far as the ribs allow.
Rushing	Reps done in a second, limbs swinging	Count three seconds out, one second pause, three seconds back.
Breath holding	Face reddens, the set feels frantic	One full breath per rep: in at the top, out on the way down.
Neck straining	Chin poking up, head lifting off the mat	Rest the head down. Tension belongs in the trunk.
Same-side movement	Right arm with right leg	Opposite arm and leg. It is a cross-body pattern for a reason.

A useful self-check is to slide your fingers under your lower back at the start. If the pressure on them changes a lot during a rep, your pelvis is moving and the range is too big.

Easier versions if the full move is too hard

There is no shame in regressing. Most people who struggle are trying too much range too soon.

• Legs only, arms held up. Keep both hands pointing at the ceiling and just lower one leg at a time, heel tapping the floor with the knee bent.
• Arms only, feet down. Feet flat on the floor, reach one arm overhead at a time. Good for people whose ribs flare easily.
• Heel taps. Keep the knee bent at 90 degrees throughout and lower the foot to tap the floor. Much shorter lever, much easier.
• Hold the position. Simply hold the start position with tension for 20 to 30 seconds, breathing slowly. Build to three rounds.

Harder versions when it gets easy

Only progress when you can do 8 slow reps per side with no change in back position. Then add one thing at a time:

• Longer pauses. Hold the extended position for three to five seconds and take a full breath there.
• Light dumbbell or plate. Hold a light weight in the moving hand. It lengthens the lever and adds challenge to the shoulder and trunk.
• Cable or band resistance. On the cable station, hold a handle at arm’s length above your chest with the cable pulling from behind your head. The cable tries to pull your arms overhead and your ribs up; you resist it while the legs move. This is one of my favourite versions because the load is constant.
• Both legs, then both arms. Lowering both legs together is a big jump in difficulty. Leave it until the single-leg version is solid.

Where it fits in a session

I use the dead bug in two places. First, in a warm-up before squats or presses: two short sets to switch on the trunk and practise breathing before the bar comes out. Our guide on how to warm up before lifting weights shows how that fits around the other warm-up work.

Second, in the core block at the end of a session, paired with an anti-rotation drill like the Pallof press and a loaded carry. Together they train the trunk to resist arching, twisting and side bending, which covers far more than crunches do. The dead bug is not about bracing hard under a heavy bar; it is about learning control at low load first, so that heavier bracing has something to build on.

Who it suits, and when to be careful

The dead bug suits almost everyone because you are lying down, the load is your own limbs and you control the range. That makes it a common choice for people coming back after time off, for desk workers whose posture has drifted, and for lifters who arch too much under the bar.

A few cautions. If you have had abdominal surgery, are pregnant or postnatal, have a hernia, or have current back pain that is getting worse, check with your GP or a physiotherapist first. Postnatally, a coach should check for abdominal separation and adjust the exercise rather than assuming a standard version suits you. The NHS has general guidance on exercise for adults if you want a starting point.

How I coach it in the studio

In a private personal training session in our basement studio on Archway Road, the dead bug often appears in week one. It tells me a lot quickly: how well someone breathes, whether their ribs flare under effort, how much hip-flexor tension they use to make up for the trunk. Then I adjust the version, the range and the tempo, and we come back to it as the main lifts get heavier. Because the studio is booked to you alone, there is room to slow it down and get it right. If you want that level of attention on the basics, our page on 1-1 coaching in Highgate explains how sessions are structured.

Questions we get asked

Should my lower back be flat on the floor?

Close to it, but not crushed. Remove the big arch with a full exhale, then keep that position steady. Pushing hard into the floor often turns into a different, tense movement.

Why do I feel it in my hip flexors?

Usually because the leg is going too low or too straight, and the front of the hip takes over. Bend the knee, shorten the range and slow down.

Is the dead bug better than a plank?

They train similar qualities in different ways. The plank is a static hold; the dead bug adds moving limbs, which makes it better for teaching control. Most programmes have room for both.

How often should I do it?

Two or three times a week is plenty, as part of a warm-up or a core block. It is low fatigue, so it fits easily around other training.

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