Straight Leg Sit-Up
Straight Leg Sit-Up Exercise Description
The Straight Leg Sit-up is a bodyweight trunk flexion exercise performed from a supine position to a tall seated position with the legs extended. It primarily trains the rectus abdominis, with assistance from the external and internal obliques, and a strong contribution from the hip flexors (notably the iliopsoas and rectus femoris). Keeping the legs straight lengthens the lever arm, increasing the demand on trunk control compared with bent-knee variations. The movement begins with controlled spinal flexion to lift the shoulders, then transitions to hip flexion to bring the torso upright. Emphasize smooth, segmental motion, a neutral neck, and steady breathing to limit momentum and maintain quality technique throughout.
- Muscle Groups: Abs, Core, Waist
- Target Muscles: Rectus Abdominis
- Assisting Muscles: External Obliques, Iliacus, Internal Obliques, Psoas Major, Rectus Femoris
- Stabilizing Muscles: Iliocostalis, Longissimus, Multifidus, Transversus Abdominis
- Body Area: Upper Body
- Body Parts: Core, Torso
- Body Surface: Front
- Body Symmetry: Other
- Equipment: Bodyweight
- Exercise Patterns: Other
- Exercise Type: Strength
- Functional Grouping: Trunk Flexors
- Joint Involvement: Multi-joint
- Muscle Location: Stomach
- Movement Direction: Vertical
- Muscle Position: Anterior
- Gender: Female
How To Do The Straight Leg Sit-Up Exercise
‘- Lie on your back with legs straight, heels on the floor, toes up.
– Cross arms over your chest or place fingertips lightly at your temples; elbows stay wide.
– Brace the abdominal wall; set a slight chin tuck to keep a long neck.
– Initiate by curling the upper back off the floor—bring the sternum toward the pelvis.
– Continue by flexing at the hips to sit tall, shoulders stacked over hips; keep heels grounded.
– Pause briefly in the upright position without collapsing the ribcage.
– Lower with control: reverse the motion, rolling down through the spine to the start.
– Keep knees extended and feet relaxed; avoid yanking the head or using momentum.
– Maintain even breathing—exhale on the way up, inhale on the way down.
Straight Leg Sit-Up Tips
‘- Keep your legs straight with heels on the floor and toes pointing up throughout the movement.
– Cross your arms over your chest or place fingertips lightly at your temples, keeping the elbows wide.
– Brace your abdominal wall before you start moving and maintain this tension.
– Set a slight chin tuck to keep your neck long and neutral.
– Start the sit-up by curling your upper back off the floor, bringing your sternum toward your pelvis.
– After the initial curl, flex at the hips to come to a tall seated position with shoulders stacked over hips.
– Keep your heels grounded as you rise to and hold the upright position.
– Pause briefly at the top without letting your ribcage collapse.
– Lower with control by reversing the motion, rolling down segment by segment through your spine.
– Keep your knees extended, feet relaxed, avoid yanking your head, and use even breathing—exhale on the way up, inhale on the way down.
Straight Leg Sit-Up Beginner Introduction
The Straight Leg Sit-up turns a simple floor movement into a more demanding challenge for the midsection. Instead of bending the knees, the legs stay long on the ground, which extends the distance between the upper body and the hips. This longer lever means the abs, side abs, and hip flexors, along with the front of the thighs, are heavily involved as the body travels from lying flat to an upright seated stance.
The motion blends a gradual curling of the spine with a strong fold at the hips, so the shoulders leave the floor first and the torso eventually arrives stacked over the hips. Because the legs are straight and remain on the ground, the trunk has to work harder to control the rise and the return. Smooth, connected movement, a relaxed yet aligned neck, and calm, regular breathing define a quality repetition, turning this into a core exercise that emphasizes control and coordination rather than raw momentum.