Exercise guide
Medicine Ball Oblique Crunch
- Intermediate
- Isolation
- Rep-based
- Waist
The Medicine Ball Oblique Crunch is a targeted core exercise that isolates the internal and external obliques by adding external resistance to a rotational crunching motion.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat with your knees bent and feet flat on the floor, hip-width apart.
- Hold the medicine ball with both hands directly over your chest.
- Tuck your chin slightly and press your lower back firmly into the floor to engage your transverse abdominis.
How to do it
- Exhale as you lift your head and shoulder blades off the floor, rotating your torso to bring the medicine ball toward the outside of your right hip.
- Pause for a second at the peak of the contraction, squeezing your side-abs (obliques) intensely.
- Inhale as you slowly lower your shoulders back to the starting position with a controlled 2-second tempo.
- Repeat the movement on the opposite side, alternating for the duration of the set.
Form checklist
- Keep your lower back glued to the mat throughout the entire range of motion.
- Initiate the movement from your core rather than swinging the ball with your arms.
- Ensure your shoulder blades clear the floor on every repetition.
- Avoid pulling your chin toward your chest; maintain a small gap to protect the neck.
Pro tips
- Focus on the 'mind-muscle connection' by visualizing your ribcage moving toward your opposite hip bone.
- Keep the medicine ball close to your torso to keep the tension strictly on the obliques rather than the front deltoids.
Make it harder
- Perform the exercise with your legs in a tabletop position (hips and knees at 90 degrees) to increase instability.
- Extend your arms further away from your chest to increase the lever arm, making the weight feel significantly heavier.
Frequently asked
- What muscles does the medicine ball oblique crunch work?
- The medicine ball oblique crunch primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
- What equipment do you need for the medicine ball oblique crunch?
- The medicine ball oblique crunch uses medicine ball.
- Is the medicine ball oblique crunch good for beginners?
- The medicine ball oblique crunch is rated intermediate. Build a base with simpler variations first, then progress to it with light load and strict form.