BOSU Spider Plank
A plank on the BOSU that adds an alternating knee-to-elbow drive, blending anti-extension bracing with dynamic oblique flexion.
Level: Intermediate
Primary: Abs
Secondary: Quads Shoulder
Movement: Isolation
Tags: Anti-Rotation Balance / Stability Core Stability
Type: Functional Fitness (Obstacle & Hybrid) ISO
Equipment: Balance Trainer
Target muscles
The rectus abdominis and transverse abdominis hold the plank, while the obliques produce the spider action as each knee tracks up toward the same-side elbow. The hip flexors drive the knee drive, and the shoulders and serratus stabilise hard against the moving, unstable base.
How to perform
Setup
Set your forearms on the dome, elbows under the shoulders, and extend into a straight-line plank. Brace the core and square the hips before you move.
Execution
Keeping the plank tight, drive one knee forward and out to the side toward the same-side elbow, opening the hip and crunching the oblique. Pause briefly, return the foot to the start without letting the hips swing, then repeat on the other side. Move slowly enough that the dome doesn't pitch you sideways. The torso should stay level the whole time — the legs do the travelling, the trunk does the bracing.
Common mistakes
- Letting the hips rock side to side as each knee comes up, which signals the core has stopped bracing.
- Dropping the hips into extension and stressing the lower back.
- Rushing the knee drives so the dome destabilises and form falls apart.
- Only half-bending the knee instead of bringing it up toward the elbow where the oblique actually works.
Progressions and regressions
Regress to a spider plank on the floor, or hold a static BOSU plank first, to build the base. Progress by pausing two seconds with the knee up, slowing the tempo, or moving to a hands-on-dome position. Adding a push-up between knee drives turns it into a tougher full-body movement.
Programming notes
Program it as core conditioning, 3 sets of 8-12 knee drives per side or 30-40 seconds of alternating work. Keep the pace deliberate so the anti-rotation demand stays high. It fits well in a circuit between pressing and pulling stations as active core work.
