The hollow hold is a total-core isometric borrowed from gymnastics — you lie on your back, press your low back flat, and hold your body in a shallow "banana" shape. Here's how to do it with good form, the muscles it works, the mistakes to avoid, and how to program it.
The hollow hold is a total-core isometric that primarily works the rectus abdominis and deep core, with the hip flexors and quads helping hold the legs up. You lie supine, press your lower back into the floor, and lift your shoulders and legs into a hollow shape you hold under tension. The key is keeping that lower back glued down the whole time — which makes it a demanding anti-extension exercise straight out of gymnastics. Regress it by tucking the knees, and build toward straight arms and legs.
The hollow hold is an isometric, so nothing moves — the whole front of the core works to keep your lower back pinned and your body in the hollow shape. The abs do the most work, with the hip flexors and quads holding the legs up.
| Role | Muscles | What they do in the hold |
|---|---|---|
| Primary mover | Rectus abdominis, deep core | Pin the lower back to the floor and resist extension |
| Assisting | Hip flexors | Hold the straight legs up off the floor |
| Assisting | Quads | Keep the legs straight and rigid |
| Stabilizers | Obliques, shoulders | Keep the trunk square and the arms reaching overhead |
Step-by-step form. The one rule that matters: your lower back stays flat on the floor. If it lifts, regress.
If you want to train the same anti-extension pattern at a different difficulty or with movement, these are the common swaps:
The hollow hold works well early in a core block or as part of a warm-up for bracing. General starting points:
| Goal | Sets × hold | Notes |
|---|---|---|
| Core strength | 3–4 × 15–30 s | Straight arms and legs, low back flat; regress the position before form fails |
| Endurance | 2–3 × 30–45 s | Longer holds, still with a flat lower back; tuck the knees if it lifts |
| Frequency | 2–4× / week | Recovers fast; progress by lowering the legs, straightening the arms, or adding time |
The hollow hold builds strong abs, but seeing them is a separate job — visible abs depend on your body-fat level and nutrition, because abs are built in the kitchen too. See cutting and nutrition for lifting for that side of it.
Log every hollow hold — the duration and number of sets — in LiftHero, and it charts your progression so you can see your holds getting longer or your position getting harder over the weeks. Slot it into a core circuit, add a rest-timer between holds, and save it into a routine so it's ready the next time you train. LiftHero records what you log; it doesn't diagnose your form.
It's a total-core isometric that mainly works the rectus abdominis and deep core, with the hip flexors and quads helping hold the legs up. It trains the whole front of the trunk to resist extension.
Both are anti-extension isometrics, but the plank is face-down on your forearms while the hollow hold is on your back. The hollow hold demands you actively pin the lower back to the floor, which many lifters find harder on the abs.
Tuck your knees toward your chest, or keep the legs higher and the arms by your sides. Both shorten the lever and make it easier to keep your lower back flat. Progress toward straight arms and legs over time.
They build strong, well-developed abs, but whether they're visible also depends on body-fat level and nutrition — abs are built in the kitchen too. Training the muscle and managing body fat both matter.
Holds of 15 to 45 seconds with a flat lower back are plenty for most people. If your back lifts off the floor, shorten the hold or regress the position rather than pushing for more time.
Track your hollow holds, watch your holds get longer, and run a real program — free on iOS.
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This guide is educational and not medical advice. Consult a qualified coach or medical professional before starting or changing a training program.
By Meitar Lazimi, founder of LiftHero · Last updated July 9, 2026.