BOSU Single Arm Plank
A plank on the BOSU with one arm lifted, forcing the core to resist rotation while the single supporting arm steadies the dome.
Level: Advanced
Primary: Abs
Secondary: Shoulder
Movement: Isolation
Tags: Anti-Rotation Balance / Stability Core Stability
Type: ISO
Equipment: Balance Trainer
Target muscles
Lifting one arm from a plank turns an anti-extension hold into a powerful anti-rotation drill. The obliques and transverse abdominis fight to keep the hips and shoulders square as the body wants to twist toward the supporting side, while the rectus abdominis stops the lower back sagging. The supporting shoulder's rotator cuff and serratus work hard to keep the dome steady under the single point of contact. The glutes and quads hold the line from heels to head.
How to perform
Setup
Set both forearms or hands on the dome in a strong plank, feet a little wider than usual for a stable base. Brace the abs, squeeze the glutes, and set a flat, neutral spine before lifting anything.
Execution
Slowly lift one arm off the dome and either reach it forward or tuck it to your side, keeping both hip bones and both shoulders pointing straight down. The body will want to rotate toward the planted arm — resist it by driving the brace and pressing hard through the supporting forearm. Hold steady for the prescribed time without the hips twisting or sagging, then return the arm and switch sides. The stillness is the work.
Common mistakes
- Letting the hips rotate open toward the planted arm.
- Allowing the lower back to sag once the arm lifts.
- Lifting the arm quickly and snatching at balance instead of moving slowly.
- Narrowing the feet so the base is too unstable to control the rotation.
Progressions and regressions
Regress to a standard two-arm BOSU plank, or perform the arm lift from a floor plank first. Progress by reaching the lifted arm further forward, holding longer, or combining it with a single-leg lift on the opposite side for a full contralateral challenge.
Programming notes
Prescribe it by time, 2-3 holds of 15-30 seconds per side, as anti-rotation core work. Keep the feet wide enough to control the twist and stop when the hips break square. It directly trains the trunk stiffness that transfers to single-arm pressing and carrying, so it complements unilateral upper-body work.
