One of my students said: “If you ever been attacked or in a situation where someone is trying to do you harm, your adrenaline goes through the roof and it difficult to think straight and getting hit adds to this difficulty and you need power to stop an attack. Just like Mike Tyson says, everyone has a plan until they get hit… I do believe you can deflect, if you’re lucky or quick enough, then move to execute a technique. Just an experience observation.”

This is an interesting and relevant point of view. And he backed it up with this video:
https://m.youtube.com/watch?v=qmeW9MQIsfM which pushes the view that power is more important than speed.

The guy in the video is right, and he’s wrong.

Power is important, but misused power can be as ineffective as no power, worse, it can work against you. This is what the unbendable arm is about – about not fighting yourself. (And everybody does fight themselves to an extent.) Still, if you have less power than the other guy in a given situation, you will lose in a head to head confrontation.

Power is not a simple thing, either. If you think of an arm wrestling contest, it is mostly about simple strength. (Yes, there are ways to use your strength more effectively there too, but it is mostly strength of certain muscles and position.) Martial arts is like cheating at arm wrestling. You know what a fair fight is? An oxymoron. A story I like is one I heard at a party when I was a kid. This gate crasher was wanting to come in to a private party. The guy on the door said if he didn’t leave in three seconds, he was going to hit him. He counted: one….two… and he hit him. Fight over.

You can be the weaker of the two, overall, and still have the greater power where it matters. In kote gaeshi, for example, to break uke’s balance it is the power at the end of uke’s arm that matters. So you can be much smaller, and still be able to do technique.

We train a lot. And that is important, because you eventually find you are reacting without thinking – what the Japanese call mushin. Tyson is right in that plans go by the board when you get hit. Training, however, does not necessarily. Good training does not. Bad training (e.g. inappropriate training, unrealistic training) does. A plan is a good thing when training. It is often counter-productive when fighting. Randori is all about training under stress, in unpredictable situations. It is about as good as it gets in the dojo, and can be very good indeed. But on the street there are no referees, and the adrenaline will be pumping more.  It is hard to replicate that amount of stress in the dojo.

Speed and power are not unrelated. In fact, energy equals mv2. So the best way to increase power is often to increase speed. Double mass, and double energy. Double speed, and quadruple energy. Big muscles can increase power, but fast muscles are also important. There is another aspect to speed. If you want to kick or punch somebody, you want all the energy to appear in the last inch or two. Energy elsewhere is irrelevant. If you want to throw somebody, you want the energy to be spread out over maybe as much as two or three feet. And it isn’t the simple integral. There are certain times in any technique where energy is more important than others. So the relevant power differs according to the technique and art. And almost all power comes from gravity. (Think about fighting in weightlessness.)

People working to bulk up often fail to work at flexibility enough, so they are tense, stiff, and their speed falls.

The things that are important for martial effectiveness include the following, not necessarily in order of importance: attitude, technique (including leverage, position, timing, etc), power, and stamina.

Where power fails is when it is overmatched, but that applies to all of the above. Combat is the weighing of the different attributes of the two sides, which lets you see which is the more useful of the two mixes in a given situation. In the dojo, you are pretty much on your own for strength, stamina, etc. All I teach is technique. Coming to class, you will get some attitude, stamina, strength, flexibility, but the focus is on technique.