Stabilizers (not highlighted): Rectus Abdominis, Internal and External Obliques, Quadriceps
Lie supine (on your back) on a bench or on a mat.
Place your hands under your buttocks to support your pelvis.
Press your lower back against the bench.
Raise your feet a little off the bench or mat.
Keeping your feet together and your legs straight, exhale as you flex your hips and raise your legs until they are vertical.
Inhale as you lower your legs to the starting position.
Comments and tips
Keep your feet off the bench or mat.
Keep your lower back pressed against the bench or mat. This is important to protect your lumbar spine.
Many people, including fitness instructors, think that the lying straight leg raise is an exercise for the rectus abdominis. However, as made clear above, the rectus abdominis only acts to stabilize the pelvis.