From a suspended plank, pull your knees toward your chest by curling the hips and spine, working the abdominals. Return under control to the straight-plank position between repetitions.
How to do the Jack Knife (Suspension)#
- Place your feet in the suspension cradles and set up a high plank with hands under your shoulders and your body in a straight line.
- Tighten your core and initiate the movement by tucking your hips and drawing both knees toward your torso.
- Allow your hips to lift as your knees approach your chest while keeping your shoulders stable over your hands.
- Pause briefly at the top, maintaining abdominal tension.
- Slowly extend your legs back out to the starting plank position with a controlled motion.
Muscles worked#
- Primary: Abs, Hip flexors
- Secondary: Obliques, Front delts, Chest, Triceps
Common mistakes#
- Letting the hips sag during the starting plank.
- Lifting the hips excessively so the movement becomes a pike rather than a core curl.
- Using momentum to swing the legs instead of a controlled abdominal contraction.
- Collapsing or shrugging the shoulders instead of keeping them stable over the hands.
