Hook feet under foot brace and lie supine on incline board with hips bent. Extend arms down to sides or cross arms on chest.
Flex waist to raise upper torso from bench. Keep low back on bench and raise torso up as high as possible. Return until back of shoulders contact incline board. Repeat.
If no knee support is built in to incline board, ball can be placed under legs. Hip and knee flexors may be involved as stabilizers if incline is steep and no calf support is used. See Spot Reduction Myth .
To make this movement easier, perform crunches on lower height incline or on flat surface.
Exercise can be made more challenging by placing hands further up toward head. See Arm Position During Waist Exercises . Exercise can also be performed on higher incline board or with additional weight.