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

How Iridium Programs This

Iridium evaluates your lateral deltoid recovery status before assigning this variation, as significant shoulder fatigue can cause your arm to fail before your obliques. If your 7-day training history allows, the system tracks hold times relative to your body weight and uses RPE to determine when to extend duration. When shoulder fatigue is high, Iridium prioritizes forearm-supported variations to ensure the core remains the limiting factor.

Form Cues

Place your supporting hand directly underneath your shoulder
Stack your feet and fully extend your legs
Drive your hips up to create a straight line from head to heels
Squeeze your glutes and brace your core tightly
Keep your head neutral and gaze straight ahead

Don't

Don't let your hips sag toward the floor
Don't allow your top shoulder to roll forward
Don't place your hand too far out in front of your shoulder
Don't let your head drop or neck strain
Don't hold your breath

Common Mistakes

Sagging hips breaking the straight line
Hand placed too far forward
Rotating the torso forward or backward
Shrugging the supporting shoulder
Bending the knees

Muscles Worked

This exercise primarily targets the obliques and the quadratus lumborum, which are crucial for lateral spinal stability and preventing lower back pain. Unlike the standard forearm version, the straight-arm position places significant demand on the lateral deltoid and rotator cuff stabilizers, strengthening the shoulder complex while engaging the glutes to maintain hip alignment.