The trunk resists movement more than it produces it. That is why bracing work belongs beside flexion work.
PrimarySecondaryNot worked
Rectus abdominis flexes the trunk. The obliques, external and internal, add rotation and side bend. Transversus, deepest, produces no visible movement — it compresses and stabilises. Under a heavy bar, most abdominal work is stopping the trunk moving, not bending it.
Ten to twenty sets a week across three families: flexion (crunches, leg raises), anti-flexion (planks, ab wheel) and anti-rotation (Pallof press). Add load rather than reps — sets of a hundred stop paying past a point.
Pulling on the neck during crunches. Hands support, they do not haul: keep the chin off the chest.
Names are the ones the app uses.
The journal, the anatomical map and nearly 300 movements, each with its own video — free to start.