Six exercises, all on the floor, all targeting the core from different angles - and none of them are easy. Crunches work the upper abs. Leg raises lift both legs together and load the lower abs, which most people discover they have been neglecting. Cycling crunches rotate the torso and bring the obliques into the conversation. Crunch kicks add a leg extension to the crunch, which lengthens the working range. Heel taps reach side to side from a crunch position and keep the obliques firing. Reverse crunches curl the hips off the floor instead of the shoulders - the opposite direction, the same relentless intent.

The abs of steel part is not a promise, it is a destination. The route there is repetition, variety, and not skipping the exercises that are uncomfortable. Every movement here targets a different part of the abdominal wall, which means there is nowhere to hide and nothing gets to rest for long.

Keep the lower back pressed into the floor throughout. If it lifts, the abs have stopped working and the back has taken over. That is not the goal.