Sit on the edge of a bench with your legs extended in front of you.
Grasp the edge of the bench for support.
Lean backward and raise your legs a little off the floor, keeping them straight and together.
Exhale as you lean forward and raise your knees toward your chest.
Inhale as you lean backward and return your legs to the starting position.
Comments and tips
Keep your back straight and your feet off the floor.
Make the seated knee raise more difficult by holding a dumbbell between your feet.
Many people, including personal trainers, think that the seated knee raise targets your rectus abdominis. In fact, this is a hip flexion exercise, so the targets are your iliopsoas (hip flexors). Your rectus abdominis isn’t even a synergist. Along with your internal and external obliques, your rectus abdominis only acts as a stabilizer of your waist and pelvis. Your rectus abdominis and obliques will become synergists only if you flex your abdomen, which is impossible if you keep your back straight.
You might even hear people saying that the seated knee raise and similar hip flexion exercises target your “lower” abs. There’s no such thing as your lower abs! Your rectus abdominis is a single muscle. When it contracts, it does so in its entirety. There are no upper and lower sections.
Also known as the seated knee-up or seated knee tuck.