reckonerDead bug
On your back, arms up, knees up, and then one arm and the opposite leg reach away while your lower back stays flat on the floor. It looks like nothing. Done with the back genuinely down it is one of the plainest tests of whether you can brace under a moving limb.
Press the lower back flat throughout.
- Pattern
- Core anti-extension
- Trains
- Abs
- Kit
- Bodyweight, floor
- Loading
- Your own bodyweight
- Reckoner prescribes
- 3 sets of 8 to 12 reps at RPE 8
- Progression step
- Nothing to add, so the sets climb instead
- Skill
- Simple to learn
- Recovery cost
- Very low
Muscles worked
How to do it
Get the back flat first
Lie down, knees bent to a right angle over the hips, arms straight up over the shoulders. Press the small of your back into the floor until there is no gap under it. If you cannot get it there lying still, nothing after this counts.
Breathe out and hold the flat
A long breath out helps the ribs settle and makes the flat back easier to keep. Hold that position. This is the reference you are protecting for the rest of the set.
Lower one arm and the opposite leg
Reach the arm back over your head and straighten the leg toward the floor at the same time, slowly. Go only as far as you can go with the back still pressed down.
Come back and swap
Return both to the start under control, then do the other pair. The set ends the moment a gap appears under your back, whatever the rep count says.
What goes wrong
Letting the back lift as the leg goes down
This is the whole exercise failing, and it is invisible unless you check. The leg gets lower, the range looks better, and the back arched to buy it. Put a hand under the small of your back if you are not sure.
Holding your breath through the reach
It makes the position feel more solid, which is why people do it. The skill you want is bracing while breathing, because that is what a heavy set of anything actually demands.
Going fast to make it feel like something
It is a quiet exercise and the temptation is to speed up until it feels like work. Speed lets momentum carry the limbs and takes the load off the thing being trained.
How Reckoner progresses this lift
Six weeks of this lift, run through the real engine. Nothing below was typed in: the prescription, the decision and the sentence beside it all come from the same code that writes your week.
| Week | Prescribed | What it did |
|---|---|---|
| 1 | 3 x 8 | More reps 8 → 9 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 2 | 3 x 9 | More reps 9 → 10 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 3 | 3 x 10 | More reps 10 → 11 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 4 | 3 x 11 | More reps 11 → 12 repsYou finished every set at RPE 7, with room left in the range, so the reps climb before the load does. |
| 5 | 3 x 12 | Deload 40% of sets offFive weeks of building, then one week lighter. About 40% of the sets come off. The load holds and your reps stay where you earned them, so you keep the strength and lose the fatigue. |
| 6 | 2 x 12 | One more set 2 → 4 setsYou hit the top of the range at RPE 7 and there is no weight left to add. When a lift runs out of load, the set is the increment, so it does four sets next week. |
Real engine output, not an illustration. Every row was produced by running the engine itself when this page was generated.
The full rule, and why the reps move before the load does, is in how Reckoner decides to add weight.
Questions people ask
This feels too easy. Am I doing it wrong?
Probably the back is coming up. Slow the reach down, take the limbs closer to the floor, and stop the set at the first rep where the gap appears. If it is genuinely easy with the back flat throughout, the hollow hold and the ab wheel rollout are the next things along.
Is this a strength exercise?
No, and it is worth being clear about it. Bodyweight trunk exercises of this kind sit below the activity level usually taken as a strengthening stimulus, which makes them better suited to training endurance and control than to building a muscle1. Load lives elsewhere in your week.
Why does Reckoner give me this rather than crunches?
They train different things. A crunch moves the spine, a dead bug stops it moving. Both are in the library and the engine picks from what your gym has and what your week already contains.
Similar movements
There is no load to ease on this lift, so Reckoner offers one of these the first time it stalls. Each of them has a page.
Sources
- Ekstrom, Donatelli and Carp, Journal of Orthopaedic and Sports Physical Therapy, 2007. Electromyographic analysis of core trunk, hip, and thigh muscles during 9 rehabilitation exercises thirty healthy adults across nine bodyweight exercises, where the side bridge was one of only three to pass 45 per cent of a maximal contraction, at the gluteus medius and the external oblique, and the quadruped arm and leg lift did so at the gluteus maximus, with every other exercise below that line and therefore better suited to endurance than to strength