The short answer
Dead bug or Plank?
Start with the dead bug if your lower back aches after planks, your wrists or shoulders object to holding your weight, or you are in the first year after giving birth. You lie on the floor, nothing loads the hands, and you feel the moment your back lifts. Move to the plank once 10 slow reps a side stay flat: it adds your body weight held against gravity. The two share a job, keeping the lower back from arching, so most people end up with one in the warm-up and the other as the main work.
Side by side
| Question | Dead bug | Plank |
|---|---|---|
| What it is | Lie on your back with arms pointing at the ceiling and knees over the hips, then lower one arm and the opposite leg toward the floor while the lower back stays down. | Face down on your forearms and toes, hold a straight line from head to heels without the hips sagging or piking. |
| Equipment | A floor and a mat | Nothing |
| The job | Keep the lower back still while an arm and the opposite leg move away from it | Keep the trunk straight against gravity while nothing moves |
| Where the load goes | The floor supports your back; the challenge grows as the limbs lower and straighten | Your weight hangs between forearms and toes; if the hips sag, the lower back takes it |
| Wrists | No load at all | None on the forearms; a high plank on the hands bends the wrists back under load |
| Counted in | Slow reps per side, usually 6 to 10 | Seconds held with a clean line |
| To make it easier | Knees bent and legs only, or a shorter reach | Knees down, or forearms on a bench |
| To make it harder | Straighter legs, a light weight or band in the hands, a 3 second pause just above the floor | Elbows further forward with the pelvis tucked, feet on a step, or one foot lifted |
| Midline stretch in healthy adults | No different from the plank on ultrasound | No different from the dead bug |
Choose the dead bug when
- Your lower back aches during or after a plank, or you cannot tell whether it is arching. On the floor you feel it lift.
- Your wrists, elbows or shoulders complain when they hold your weight.
- You are back to exercise after giving birth, cleared to start, and want a trunk move where you can watch the midline and stop a rep if it bulges.
- You are starting from nothing and want a move with many easy steps before it gets hard.
Choose the plank when
- Ten slow dead bugs a side are easy and your back stays flat. The control is there; what you need now is load.
- You are working toward push-ups. A push-up is a plank that moves, and many beginners sag at the hips before the arms tire.
- You want a simple test to repeat: seconds on a clock, compared week to week.
- You lift, and want the trunk used to holding still while the shoulders take weight.
Using both in one week
The dead bug teaches the brace and the plank loads it. Early on, two or three days a week, do the dead bug first, 6 to 10 slow reps a side for 2 or 3 sets, then 2 or 3 plank holds. End each hold when your line changes, whatever the timer says. Once both feel easy, the plank takes over the progression (a tucked pelvis, a longer lever, feet raised) and the dead bug becomes part of the warm-up.
From the first dead bug to a hard plank
- Dead bug, legs only, knees bent at a right angle: tap one heel to the floor and bring it back, 2 or 3 sets of 6 to 10 a side. Move on when the lower back stays down on every rep.
- Full dead bug: opposite arm and leg together, the leg straightening as it lowers, breathing out on every reach. 3 sets of 6 to 10 a side, then add a 3 second pause just above the floor. Move on when 10 a side are slow and flat.
- Plank with the forearms on a bench, or with the knees down: 3 holds of 20 to 30 seconds.
- Forearm plank on the toes: 3 holds of 20 to 45 seconds, each one ending before the hips drop.
- Long-lever plank: elbows a hand's width further forward, glutes squeezed, pelvis tucked under. The longer lever and the tuck each raised abdominal activity when tested, so expect holds of 10 to 20 seconds.
The numbers
- Forearm plank to failure
- 124 s for men, 83 s for womenAverages for 471 college students, with a spread of about a minute either way. Athletes held longer than non-athletes (Strand 2014).
- Midline stretch, plank vs dead bug
- No differenceUltrasound of the linea alba in 13 healthy adults. The deepest abdominal muscle, the transversus abdominis, thickened about the same in both (Bini 2021).
- Pelvic floor training after birth
- 37% lower odds of leakingUrinary incontinence in the first postpartum year, 7 trials and 1,930 women, moderate certainty (Beamish 2025).
- Six weeks of planks and dead bugs for low back pain
- Disability down 29% and 39%Two home groups, 30 finishers: scores went from 15.9% to 11.3% and from 13.0% to 8.0%. Both groups exercised, so nothing here is compared with doing nothing (Devorski 2025).
Mistakes that cost the most
- Holding your breath through the plank. If you cannot breathe in the position, it is too hard: drop the knees or shorten the hold.
- A rushed dead bug. Fast reps let momentum do the work, and the slow lowering is the exercise.
- Lowering the leg further than you can control. The rep ends where your back starts to lift, even if that is 30 cm (1 ft) above the floor.
- Adding minutes once the plank passes a minute. Change the position instead: tuck the pelvis, move the elbows forward, or lift a foot.
Questions people ask
Dead bug or plank: which should I learn first?
The dead bug, for most beginners: the floor tells you the moment your back arches. Add the plank when you can do 10 slow reps a side with the back down the whole time. If you already hold a clean 30 second plank without back ache, do both.
Is the dead bug or the plank better?
The plank is harder; the dead bug is easier to do well. In one ultrasound study of 13 healthy adults, the deepest abdominal muscle thickened about the same in both and neither stretched the midline more. Choose by what your body tolerates now: control from the dead bug, load from the plank.
Are dead bugs better than planks for a bad back?
Often, at first, because the floor supports your back and you set the difficulty by how far the limbs travel. In a 2025 trial in nonspecific low back pain, six weeks of home planks, side planks, dead bugs and bird dogs went with lower disability in both groups. Every group exercised, so it shows the moves were tolerated, not that they fixed anything.
Sources
- Comparison of linea alba length and core-muscles engagement during core and lower back orientated exercisesJournal of Bodywork and Movement Therapies, 2021
- Norms for an isometric muscle endurance testJournal of Human Kinetics, 2014
- An electromyographic comparison of a modified version of the plank with a long lever and posterior tilt versus the traditional plank exerciseSports Biomechanics, 2014
- Impact of postpartum exercise on pelvic floor disorders and diastasis recti abdominis: a systematic review and meta-analysisBritish Journal of Sports Medicine, 2025
- Gamified delivery of at-home rehabilitation for individuals with nonspecific low back pain: a randomized controlled trialDisability and Rehabilitation, 2025
Figures on this page come from the studies above or from the arithmetic shown. Read how claims are reviewed and updated in How the guides are written.