Boston Crab
Submission
The Boston crab is a spinal-lock submission borrowed from catch wrestling: from crab ride or a rolling exchange you turn the opponent face-down, hook both of their legs under your armpits, and sit back onto their lower back while lifting the legs, arching the lumbar spine. Genuine finishes exist in MMA and no-gi grappling, but it is a fringe attack — and as a spinal lock without a joint target it is illegal under IBJJF rules and many grappling rulesets.
Quick Reference
Key principles
- · It is a spine attack, and rulesets treat it that way: confirm legality before it ever appears in competition preparation.
- · The turnover is the technique — the crab ride's leg control is what rotates them face-down with your hooks already threaded.
- · Sit on the lower back and hips: sitting too far up their back tips your weight where they can roll it forward and out.
- · The legs lift and fold toward their head while your hips drive forward — the arch comes from both directions at once.
- · Their arms are free the whole time; expect them to crawl and roll, and finish before their base rebuilds.
Execution
- 1 From crab ride or a rolling scramble with both of their legs controlled, steer them face-down.
- 2 Thread both of their legs under your armpits, clamping above the ankles with your elbows tight.
- 3 Step over their body and sit down onto their lower back and hips.
- 4 Lean back and drive your hips forward while folding their legs toward their head.
- 5 Increase the arch gradually to the tap, and abandon it for the back or turtle attacks if their crawl breaks the seat.
Common mistakes
- × Sitting on the shoulder blades, where their bridge-and-roll unseats you and the arch never loads the lumbar spine.
- × Hooking the legs loosely at the ankles so a strong kick strips both hooks at once.
- × Applying it in rulesets where spinal locks are banned — the tap you get may cost the match.
Do it from
Positions and situations where the Boston Crab shows up.
