Exercise guide
Sitting Thoracic Spine Flexion
- Beginner
- Isolation
- Timed hold
- Back
- Shoulders
- Upper arms
This isolation exercise targets the upper rectus abdominis while improving thoracic mobility by focusing on controlled spinal flexion. It is highly effective for developing mind-muscle connection with the core and relieving mid-back stiffness.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Sit upright on the edge of a flat bench with your feet planted firmly on the floor, shoulder-width apart.
- Place your hands lightly behind your head with elbows wide, or cross your arms over your chest.
- Engage your core and ensure your pelvis is in a neutral position, anchored to the bench.
How to do it
- Exhale and slowly curl your upper back forward, tucking your chin slightly and pulling your ribcage down toward your belly button.
- Focus on articulating only the middle and upper spine, keeping your lower back and hips completely stationary.
- Pause for one second at the point of maximum contraction, squeezing your abdominals tightly.
- Inhale as you slowly reverse the movement, returning to a tall, upright seated position.
Form checklist
- Keep your lower back (lumbar spine) still; the movement should occur from the mid-back up.
- Avoid pulling on your neck with your hands; let the abs drive the flexion.
- Ensure your hips do not tilt or lift off the bench during the movement.
- Maintain a slow, controlled tempo to prevent using momentum.
Pro tips
- Imagine a hinge located right at the bottom of your sternum and focus all the folding movement around that specific point.
- Visualize 'shortening' the distance between your sternum and your belly button to maximize upper abdominal recruitment.
Make it harder
- Hold a light weight plate or medicine ball against your chest to increase resistance.
- Extend your arms straight overhead to increase the lever arm and difficulty of the flexion.
Frequently asked
- What muscles does the sitting thoracic spine flexion work?
- The sitting thoracic spine flexion primarily targets the abs, and also works the rhomboids and trapezius as secondary muscles.
- What equipment do you need for the sitting thoracic spine flexion?
- The sitting thoracic spine flexion requires no equipment — just your body weight.
- Is the sitting thoracic spine flexion good for beginners?
- Yes. The sitting thoracic spine flexion is a beginner-friendly movement and a strong foundation to build on.