Roll the ball away on your forearms and fight to pull it back.
Keep hips tucked and back flat, never let your low back sag at full reach.
As the ball rolls away and your body lengthens, the abs have to resist your spine collapsing into an arch, which is anti-extension training at its purest, then they haul the whole line back in to finish the rep. The further the ball travels, the longer the lever and the more brutal the demand. It builds the same rigid trunk that heavy squats and presses depend on, which is why it shows up in serious strength programmes, not just ab circuits.
Same movement pattern, but the ball's height makes it meaningfully easier, so it is the better entry point. Own long, controlled reps on the ball first, then graduate to the wheel when you want more.
Only as far as you can go with your lower back staying flat and hips tucked. The rep ends where your back starts to sag, and that distance grows naturally as you get stronger.
Your hips are untucking and your spine is arching at full reach. Squeeze your glutes, shorten the roll, and rebuild range gradually, the exercise should live entirely in your abs.
