A seated crunch on the end of a bench that draws the knees in as the torso comes forward to meet them. It works the abs from both ends and needs no floor space.
Primary muscles
Secondary muscles
This information is general fitness guidance, not medical advice. Stop if you feel pain and consult a qualified professional.
Main muscles working (thicker lines)
Sit on the end of a flat bench holding its sides, lean back about 45 degrees and extend your legs out in front of you slightly below parallel.
Brace your abs and keep your chest up.
Pull your knees in toward your chest while bringing your torso forward to meet them.
Pause for a second in the tucked position.
Extend your legs and lean back to the start without letting your feet touch the floor.
Breathing: Exhale as you tuck, inhale as you extend.
Knees and chest meet in the middle
Feet stay off the floor
Smooth, even tempo
Rocking back and forth for momentum
Hunching the shoulders instead of curling the abs
Letting the feet touch down between reps
Grip the bench firmly and sit far enough onto it to stay balanced.