Tai Chi Movement

In Tai Chi, there are 13 main types of movement called the Eight Gates and Five Steps. This is a type of categorization that is used to analyze moves in a fight. Here I will explain what they are and how they apply to combat sports. Tai Chi is more focused on clinching than other ranges of fighting, so these movement styles are usually presented from that perspective.

The Eight Gates are elements of martial arts techniques:

1. "Ward Off" is posture, especially keeping the opponent at the right distance from your body for what you want to do. It is also "having a good fighting stance." Keeping your hands up is good "Ward Off" in boxing. One example from grappling is "framing" when you are on the bottom and you are trying to avoid someone getting decent side control on you.
2. "Press" is staying on the opponent - the same concept as "being sticky" - keeping in contact with the opponent so they can't get out of range. In MMA this could be grabbing someone in a Thai clinch to avoid their kicks. In boxing it could be continuously jabbing to judge distance and keep pressure on the opponent.
3. "Yield" is getting out of the way. When someone pushes at you too hard, you can unbalance them by moving or turning in such a way that they miss most or all of your body. In boxing this could be bobbing and weaving. In grappling if someone is completely overpowering you in the clinch, and you realize you will soon be thrown, and you manage instead to pull guard for a more neutral potion on the ground, this would be another example of yielding movement. In the clinch, if you briefly turn away from your opponent in order to get a Russian tie arm bar, this is actually be categorized as a "roll back", an arm bar as a result of a yield.
4. "Push" is an attack that accelerates AFTER contact is made with the opponent. In boxing simply shoving the other boxer would be a push. In grappling, going from guard to a "hip bump" to get into full mount is an example of a pushing attack.
5. "Pluck" is to unbalance an opponent by pulling on them. In Muay Thai if you pull someone with an over hook or under hook in order to sweep them, this is an example of plucking. In grappling most ankle picks are examples of plucks.
6. "Strike" (or "Elbow") is opposite of Push, it is an attack that fully accelerates before it makes contact with the opponent. Most punches, kicks, knees, elbows etc. are strikes. In grappling striking movement is usually forbidden, but in MMA raining down elbows in mount would be an excellent example of strike.
7. "Bump" (or "Shoulder") is an attack that begins to accelerate before it makes contact with the target, but tries to keep going at the same speed after it makes contact with the target. In Tai Chi this is a shoulder check, not entirely unlike what you see in some team sports like American Football. In kick boxing a "push kick" intended to knock the opponent back is a good example of a bump. Using a Judo-type foot sweep in grappling, which is moving quickly before it makes contact with the targets leg, and is supposed to keep on moving after it makes contact, is another example of bump movement.
8. "Split" is moving the opponent's body into two different directions, like blocking the back of their leg with your knee, and then pushing them over your knee... or standing arm bars. In Muay Thai a clinch sweep that aims to make the target's upper body go in a different direction than their lower body could be considered splitting. Virtually all arm bars in submission grappling would be considered splitting in Tai Chi. A "snap double" take down where your head goes forward into their abdomen while your hands pull on the back of their knees is another example of splitting.

The Five Steps are working for position:

1. "Rooting" is being able to resist moving when someone is trying to move you, for example when someone tries to shove you and then nothing happens and you hold your ground with your feet not moving significantly, this is rooting. Keeping your knees bent in boxing so that you don't get knocked around easily by the force of oncoming punches is good rooting. In grappling, if you have a low mount, and you put your feet in the prayer position to make it difficult for the opponent to throw you off of them, this is an example of rooting.
2. "Forward step" is moving towards your opponent just like in boxing. In grappling this could be transitioning from a low mount to a high mount.
3. "Backwards step" is moving away from your opponent, as footwork would normally allow in stand up fighting. On the ground, a back door escape from mount would be an example of backwards step.
4. "Left step" is moving to your left around the opponent, as footwork normally allows in stand up fighting. On the ground, going from side control with your right side closer to your opponent's head to full mount would be an example of step left step.
5. "Right step" is moving to your right around the opponent, as footwork normally allows in stand up fighting. On the ground, going from side control with your left side closer to your opponent's head to full mount would be an example of step right step.

Tai Chi is usually cross trained (with other Kung Fu styles,) and I think part of why is because Tai Chi by way of this above theory begs the analysis of other styles. And as you have guessed by now I think the best way for Tai Chi people to learn more about this kind of movement is to cross train in kick boxing or MMA.