1. Control your opponent's wrist with one hand. With your other hand, grab one or more of your opponent's fingers tightly -locking fewer fingers will make the technique more effective.
2. Hyperextend the fingers by pulling them in a direction outside of their range of motion - try bending the fingers towards the knuckles. Fingers can also be bent and twisted sideways.
3. A thumb compression lock can also be applied by curling it into itself and pressing the tip of the nail down into the palm of the hand.
By martial arts expert Markos Markou www.markstraining.com
Illustration by Nick Hardcastle