Straight Leg Sit-Up
Straight Leg Sit-Up Exercise Description
The Straight-Leg Sit-up is a bodyweight trunk-flexion and hip-flexion exercise that strengthens the anterior core and hip flexors. With the legs extended, the motion begins as a controlled spinal curl (bringing the ribcage toward the pelvis) and transitions into hip flexion to finish in an upright, tall seated position. Primary muscles include the rectus abdominis, with the external and internal obliques assisting, while the iliopsoas and rectus femoris contribute during the sit-up phase. Emphasizing a smooth, segmental roll-up, a neutral neck, and steady abdominal bracing helps focus the work on the trunk rather than momentum. A deliberate, equally controlled return to the floor reinforces core control through a long range of motion.
- Muscle Groups: Abs, Core, Waist
- Target Muscles: Rectus Abdominis
- Assisting Muscles: External Obliques, Iliacus, Internal Obliques, Psoas Major, Rectus Femoris
- Stabilizing Muscles: Multifidus, Transversus Abdominis, Vastus Intermedius, Vastus Lateralis, Vastus Medialis
- 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: Other
- Muscle Position: Anterior
- Gender: Male
How To Do The Straight Leg Sit-Up Exercise
‘- Lie supine with legs extended together, heels on the floor, toes pointing up; keep hips and knees straight.
– Cross arms over chest, or lightly support the head with fingertips near the ears; keep elbows wide and avoid pulling the neck.
– Brace the abdominal wall and gently posteriorly tilt the pelvis to flatten the low back against the floor.
– Exhale and initiate by curling the head, neck, and shoulders off the floor, drawing the ribs toward the pelvis.
– Continue the curl through the mid-back; then flex at the hips to sit tall with the chest lifted and ribs stacked over the pelvis.
– Pause briefly in the upright position with shoulders down and neck long.
– Inhale and reverse with control: hinge back slightly, then lower the spine to the floor one segment at a time, keeping heels grounded.
– Keep the movement smooth; avoid throwing the arms, jerking, or letting the legs lift.
Straight Leg Sit-Up Tips
‘- Keep legs straight with heels on the floor and toes pointing up throughout the movement.
– Cross arms over the chest or lightly support the head with fingertips, keeping elbows wide.
– Avoid pulling on your neck when the hands are by the head.
– Brace the abdominal wall and gently tilt the pelvis back to flatten the low back against the floor before you start.
– Exhale as you curl the head, neck, and shoulders off the floor, drawing the ribs toward the pelvis.
– Sit up until your chest is lifted and your ribs are stacked over your pelvis in a tall, upright position.
– Keep shoulders down and neck long when you reach the top.
– Inhale as you reverse the motion, lowering the spine to the floor one segment at a time.
– Keep the heels grounded and the movement smooth, avoiding arm swinging, jerking, or letting the legs lift.
Straight Leg Sit-Up Beginner Introduction
The Straight-Leg Sit-up is a bodyweight core move that blends a slow curl of the upper body with a bend at the hips to reach a tall seated posture. With the legs stretched out on the floor, the motion gradually brings the chest toward the thighs, emphasizing control rather than speed or swinging. This pattern challenges the abs and side abs first, with the hip flexors and the front of the thighs stepping in more as the torso lifts higher.
This exercise highlights smooth, continuous movement through the spine and a steady midsection from the first inch off the floor to the top position and back down again. The return to the starting position mirrors the lift, with an unhurried rollout of the back onto the ground, encouraging strength through a large movement arc. Because the neck and shoulders are carried in a relaxed, aligned way while the trunk works hard, the emphasis stays on building core strength and coordination instead of relying on momentum.