Exercise guide
Half Sit-Up
- Beginner
- Compound
- Rep-based
- Waist
The half sit-up targets the rectus abdominis by focusing on the initial phase of spinal flexion, providing constant tension while minimizing lower back strain compared to a full sit-up.
Reviewed by the Crucible team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat with your knees bent at approximately 45 degrees and feet flat on the floor, hip-width apart.
- Place your hands lightly behind your ears or cross them over your chest to avoid pulling on your neck.
- Tuck your chin slightly toward your chest and press your lower back firmly into the floor.
How to do it
- Exhale and contract your abdominals to lift your head, shoulders, and upper back off the floor in a smooth, controlled motion.
- Stop the movement once your shoulder blades are completely off the mat (roughly 30-45 degrees), keeping your lower back in contact with the floor.
- Hold the peak contraction for a split second, then inhale as you slowly lower your torso back to the starting position.
- Maintain a controlled tempo of 2 seconds up and 2 seconds down, avoiding the use of momentum.
Form checklist
- Keep your lower back pressed into the mat throughout the entire range of motion.
- Ensure your feet stay flat on the ground; do not let them lift as you rise.
- Lead with your chest toward the ceiling rather than pulling your chin toward your knees.
- Keep your elbows flared out if your hands are behind your head to prevent neck strain.
Pro tips
- Focus on the 'rib-to-pelvis' connection, imagining you are folding your ribcage down toward your hip bones.
- Maintain a small gap between your chin and chest—imagine holding a tennis ball there—to ensure neutral cervical alignment.
Make it harder
- Extend your arms straight overhead to increase the lever length and resistance.
- Hold a light weight plate or dumbbell against your chest to add external load.
Frequently asked
- What muscles does the half sit-up work?
- The half sit-up primarily targets the abs, and also works the erector spinae as secondary muscles.
- What equipment do you need for the half sit-up?
- The half sit-up requires no equipment — just your body weight.
- Is the half sit-up good for beginners?
- Yes. The half sit-up is a beginner-friendly movement and a strong foundation to build on.