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

How Iridium Programs This

Since this movement utilizes a static plank hold, it generates significant fatigue in the anterior deltoids alongside the lower abs. Iridium checks the recovery status of your shoulders based on recent training volume to ensure they can support the movement without limiting your core work. The AI also tracks your repetition performance relative to your current body weight to accurately gauge progressive overload.

Form Cues

Start in a high plank with your shins resting on the center of the ball
Press your hands firmly into the floor to keep shoulders active
Exhale as you tuck your knees toward your chest using your lower abs
Allow your hips to lift slightly as your knees come in
Extend your legs back slowly to the starting position

Don't

Don't let your lower back sag or hyperextend at the bottom
Don't use momentum to jerk the ball forward
Don't let your shoulders shrug up toward your ears
Don't drop your head; keep your neck neutral

Common Mistakes

Sagging hips (lumbar extension)
Rushing the extension phase
Rounding the upper back excessively
Placing hands too far forward
Resting on toes instead of shins

Muscles Worked

This exercise primarily targets the rectus abdominis, specifically the lower region, and the hip flexors as they work to pull the knees toward the chest against instability. It also heavily engages the anterior deltoids, triceps, and serratus anterior to maintain a rigid plank position, while the transverse abdominis acts to stabilize the spine throughout the dynamic movement.