Double Leg Takedown
From FightWiki
One of the most basic and common takedowns. Derived from amateur wrestling. Usually set up with a glancing jab or straight punch. The fighter 'shoots' in towards the opponent's mid-section wrapping their arms around both legs. At this point the fighter can pull in both legs bringing the opponent off balance and to the ground or the fighter can shift his hips under the opponent and lift him up in the air and slam them to the mat. There exist two primary types of double takedowns. The normal variety and the Spear or Russian Double. The normal variety is generally not preferred in MMA because it forces the fighter to leave his neck to the outside of his opponent's body, perfect position for a guillotine choke. The Spear Double is derived from a football tackle and it requires the fighter to place his forehead square into his opponents chest, wrap or snake his arms around the legs, and drive through the opponent.
PRINCIPLES
Level change
Changing levels involves the lowering of your hips (with good posture) to bring you closer to the ground, helping to bypass your opponent's defences and put you in almost a "starting blocks" position from which you can perform a powerful and quick shoot.Change levels by bending the legs and dropping your hips, NOT by bending forward.
Penetration
A penetration step takes you inside your opponent's defences and within range of his legs.
There are two main types of penetration step:
Center step: This places your lead (penetrating) leg between your opponent's legs and is most commonly used with the Double Leg and Fireman's Carry.
Outside step: This places your lead (penetrating) leg on the outside of the leg you are attacking and is most commonly used with the Single Leg and High Crotch.
Penetration can be to your foot (snatch variation) or continued forward onto your knee.
Specific tips for the Double leg
The knee of you penetrating leg should land AT LEAST between your opponent's feet, and preferably beyond, making it difficult for your opponent to sprawl.
Drive your lead (inside) shoulder into and beyond the opponent's hips/pelvis transferring the momentum of you penetration into his body.
Keep your opponent's knees under, or in front of, his/her hips by pulling in on the backs of the knees. This will help to prevent a sprawl.

