Leg sweeps are a great setup to a string of offensive techniques. If your opponent has poor stances, a foot sweep can knock one of their legs out from under them, causing them to stumble. This atemi will cause a brief moment where the opponent must take their mind off of the fight as they scramble to keep themselves upright; the opponent is completely vulnerable to attack in that moment. This is why stable stances are so important -- because the punishment for a poor stance is a leg sweep. A well-timed leg sweep can literally sweep your opponent off of their feet, dumping them onto the ground.
[Successful leg sweep from the side, with no part of the uke touching the ground.]
Keep in mind that there was nothing special about that technique you just saw -- it was just a basic leg sweep -- but in the martial arts, and in life, there is nothing more spectacular than simple things done extremely well. The secret is in the timing -- when the opponent is stepping forward, sweep his leg just before they set in their stance (that is, before they put any weight on that leg). If you can’t dump the opponent, don’t feel bad -- a leg sweep does not need to takedown the opponent to be effective -- it only needs to disrupt their balance.
To execute a leg sweep, first notice your opponent’s stance -- if it is wider or narrower than the width of their shoulders, or if they are in the middle of transitioning to some other stance, then you can proceed. If your opponent is in a solid stance, do not attempt a leg sweep; your foot will just awkwardly bounce off your opponent just the same as it would if you tried to foot sweep a tree, or a load-bearing column.
To sweep your opponent, step your rear leg up to (but not past) your front leg, just like in a step-up front kick. The sweep itself takes on a J-shaped path. First, swing your foot diagonally out to the side a little bit, and then quickly snap your foot across your body in a straight line, until it is directly in front of your rear leg. When done properly, the knife-edge of your foot will sweep along the floor, like a broom. The ball of your foot should contact the opponent’s ankle. Do not stop when you feel your foot make contact; there is no polite way to foot sweep someone.
After executing a foot sweep, you will be awkwardly standing on one foot, so you need to quickly recover. Immediately pull your knee up to your chest, entering a fighting crane stance. A foot sweep followed by a front kick makes a winning combination, just like peanut butter and French toast. (No seriously, try that. It’s amazing.) This way, if your sweep succeeds, you can strike your stunned opponent -- and if the sweep fails, the kick will keep your opponent on defense while you recover.
[Leg sweeps In the air from the front and the side, in the air, fast and slow.]
Leg sweeps should always be directed at the opponent’s front leg. If you can reach the opponent’s rear leg, then you are also close enough to be punching, kicking, etc., and should concentrate on those things instead. It doesn’t matter if you sweep the inside or the outside of an opponent’s leg, as both will disrupt their balance. Leg sweeps should never contact the opponent any higher than the ankle. There are two reasons for this:
- High foot sweeps can injure your training partners, and if you break your partner, you do not receive a new one. The difference between a very high foot sweep and an inside crescent kick to the side of the knee is purely semantic.
- Foot sweeps use the leg as a lever to rotate the body. Sweeping as far down the leg as possible will maximize your leverage, and thus maximize the power of your foot sweep.