BOSU Side Plank with One Leg Up

Target muscles

The side plank is an anti-lateral-flexion hold: the obliques and quadratus lumborum on the down side work to keep the hips lifted and the body in a straight line. Raising the top leg recruits the gluteus medius and hip abductors of that leg and increases the demand on the bottom-side core to resist collapsing. The shoulder stabilisers steady the supporting arm, and the dome's instability sharpens every correction.

How to perform

Setup

Set one forearm on the dome with the elbow under the shoulder, and stack your feet with the body turned sideways in a straight line. Brace the obliques and lift the hips so there is no sag at the waist.

Execution

Once the side plank is solid, raise the top leg toward the ceiling and hold it at hip height or higher, keeping the hips stacked and lifted. Resist the urge to let the top hip roll forward or the bottom hip drop — both hip bones should point straight ahead. Keep pressing the down forearm into the dome to hold the shoulder strong and the body still. Hold for the prescribed time, then lower the leg, switch sides, and repeat.

Common mistakes

• Letting the bottom hip sag toward the floor so the line breaks.
• Rolling the top hip and shoulder forward out of the side-on position.
• Dropping the raised leg below hip height as the glute fatigues.
• Letting the supporting elbow slide on the dome from lack of downward pressure.

Progressions and regressions

Regress to a standard side plank with both feet stacked, or perform it on the floor before adding the dome. Progress by extending the hold time, adding small leg pulses, or reaching the top arm overhead for a longer lever.

Programming notes

Prescribe it by time, 2-3 holds of 15-30 seconds per side, as lateral core and hip work. Stop when the hips start to drop rather than grinding shaky time. It builds the lateral stability that protects the spine in carries and single-leg work, so it pairs well with loaded carries and unilateral lower-body training.