Exercise movement reviewed by:Marie Braga, PT, DPT, CSCS

How Iridium Programs This

Iridium programs this bodyweight movement as a volume-focused accessory, relying on RPE scores rather than weight to track progressive overload over time. To protect your performance on heavy compound lifts, the AI monitors oblique-specific fatigue separate from the rest of your core and adjusts set volume to ensure stability is not compromised.

Form Cues

Press your lower back firmly into the floor
Lift your shoulder blades slightly off the ground
Crunch your rib cage toward your hip bone laterally
Exhale sharply as you reach for your heel
Maintain a neutral neck position with a slight chin tuck

Don't

Don't arch your lower back off the floor
Don't pull on your head or strain your neck forward
Don't swing your body using momentum
Don't let your shoulders drop back to the floor between reps

Common Mistakes

Arching the lower back
Straining the neck forward
Rushing the tempo
Insufficient lateral range of motion
Holding breath during the movement

Muscles Worked

This exercise isolates the internal and external obliques through lateral flexion, which is crucial for rotational power and side-to-side stability. While the obliques do the heavy lifting, the rectus abdominis (upper abs) remains isometrically engaged to keep your shoulders elevated, providing a comprehensive core burn.