Have you ever failed to execute a technique in class as demonstration?

Yes, I have. A kick causes me to lose balance, for example. Or, a lock requiring a step - and I forget the step. Or, I intend to demonstrate a technique and end up demonstrating a variation. Or, I demonstrate a form and forget a movement. Or, in demonstrating a sparring combination, it didn't go as planned. Or, a break get missed.

It's not like it happens all the time, but, I'm human and occasionally make mistakes. I apologize, fix it, and move on. The one thing I have never consciously done was try and hide a mistake. If I make a mistake, I own up to it. All of my instructors have, at one time or another, made a mistake, owned up to it, and moved on. I'm no different.

There are instructors who try not to get into that situation at all: sometimes, they rely on senior students to do the demonstrations, etc. They can make the mistakes, but, it's hard to tell if the instructor can pull off the technique or not since you never seem them do it. I'm not like that: If I want a technique done, I demonstrate it. I'm not particularly flexible, so, I will enlist the aid of a student who is flexible and can do the technique, but, I will also do the technique.

I think one of my problems is I sometimes get caught monologging... I start talking about something, I forget what I'm doing, and then I mess up what I'm trying to demonstrate. After thinking of your question, I rarely make technical mistakes when testing or competing, such as in forms or breaking, though, in sparring, I'm not that great - so I make a lot of mistakes here. So I'm curious now, what you mean by mistake?

Two people can look at a third doing a technique; one says he's not doing it properly, the other says he is. Who's right? What about an instructor who doesn't kick very high... is that a mistake? When I do a form, I sometimes don't land exactly on the spot I started. Is that a mistake? Yes, I've brain-farted before, and in the middle of a form, my mind has gone blank - couldn't figure out what the next movement was if my life depended on it.

And what about non-technical mistakes: an instructor pairs off two people for sparring who shouldn't be sparring together. Or who pushes a student too far and that student gets injured?

I am both an instructor and a student. It seems foolhardy to suggest an instructor would never make a mistake, but that same person as a student can make mistakes. such a person making a mistake while in the context of a student is still an instructor making a mistake.

I would never believe someone who told me they never made a mistake.

Yes I have once or twice and usually it was because I was not paying attention or not really into being committed to the technique and executing it like it should have been executed. In a real situation neither of these two things would have been a factor. Sometimes when you are coaching or teaching six days a week, several hours per day each day you get a little bored or sometimes tired and maybe don't pay attention to what you are teaching, demonstrating, or doing for a few seconds or minutes. Then you just have to laugh at yourself some and take it in stride and get things back on track. Otherwise what you are alluding to in some ways has never happened to me simply because a technique does not work or is not something that would be effective.

I agree with the others here, many many times as a student but never as an instructor. To be a quality instructor you should know everything you are teaching simply by muscle memory alone which would mean it doesn't fail. If you are failing to show the technique correctly then you do not know the technique with complete control and therefore should not be instructing it. Of course when it comes to a balance problem or a one of flaw then i suppose that could happen to anyone but its not a good look to students.

Though i am not an instructor and still have alot to learn, i have seen my instuctor mess up a couple times when he gets lost in his thoughts

As a student many time. But not as an instructor. As an instructor we often have to change or transition to a different application. But that is not a fail. The change happens because someone does something different. Therefore, we must be able to adapt to the current situation with something appropriate.

Example we may be teaching a redirection into an arm bar when the attackers tries to punch you in the face. The attacker/student or assistant instructor does something different. So now instead of the arm bar we might have to switch to a take down then an arm bar.

This happens all of the time when you have that one what if student. What if you do this. That is the student that don't believe you can do it to them. Then when you modify what you were doing because they changed that mean we must adapt.

Another example of a change we will do as an instructor.

Example:

When teach a technique to defend against a take down like a double leg or single leg take down I will give a student X amount of time to do the counter. If they don't do it right I will try to talk them through it. But after so much time I will show them they don't have all day. So I'll counter and take them down and choke them out or use a joint lock. Of course the student resists and tries to do something. So in the middle of the take down I see they are going to end up off of the mat or into a wall. That is fine for the street. I'll tell my students to use the wall, ground, etc. But as an instructor I must look out for the safety of my students. So I'll turn and move them away from the environmental danger and put them own in a more safe environment.

Edit:

I don't know if you call this a fail, but I wouldn't. My instructor was hosting a demonstration. I was recovering from having surgery on my tib/fib from being in a car accident. I had just started to come back to class. I was still tying to build my leg back and regain some of my balance. There were instructors from all over and different styles. I only showed up to support my sensei. I hadn't planned on doing anything because I was still hurting and limping and out of practice. But my sensei put me on the spot and called me demonstrate a few things. I should have known better...lol So he sent a brown belt to attack me. He asked if we needed the mats. I told him no because I wasn't going to throw him. I told him I would just demonstrate a few self defense applications and we get out of the way. I told him to just attack me I don;t care what you do I will counter it. I spoke to the crowd to explain that. He attacked when he was ready and I countered. We did a few tings. Every attack was different and so was the counter. I told him we would do one more and call it a day. He agreed. This time I had a plan..lol I was going to end the threat with me using a joint lock from the strike. I was about to explain to him what we were going to do as this was going to be the only one that was scripted. Bu while we I was telling the crowd this was going to be the last one and we were walk toward the center of the floor he attacked me. He went for a double leg take down. At that point everything went out of the window. (Mushin) My training just took over. I didn't see him. I didn't know who it was. The attack was a real threat. Before I knew it I threw hi on that hardwood floor. After he hit the ground I was on top and was about to break his nose I and then saw his face and realized it wasn't a threat and I pulled the punch not to hit him. I got up and helped him up and had to see if he was alright. He was fine. I'm glad he knew how to fall. I apologized for throwing him like that. We laughed about it and move on. Some may call it a fail because I didn't do the application that I was planning. But I don't call it a fail because I effectively countered the attack. You could hear the crowd hold their breath. I thanked the crowd while thy applauded and I limped of the floor. Later after more therapy my leg wasn't getting better so I had to have more surgery. But I still have problems with the leg as far as pain and swelling and some nerve damage. But I still can adapt at defend myself and teach others.

That depends on what you consider a fail. Things you learn from are not failures. You need to do things wrong in order to learn how to do them right.

I don't pretend to be perfect and I tell my students that I am not perfect. As a teacher I simply know more than they do and I am willing to share what I know. Am I perfect at it? No, of course not. I am still also a student of martial arts and will remain a student as long as I live. I am getting older, had 2 knee surgeries and my kicks are nowhere where they used to be but I fully expect my students to have better kicks than mine are now. It would be unfair not to teach them just because I can't do them well anymore.

Sure there were other occasions when I wanted to demonstrate something and my partner didn't give me what I needed for that specific technique so I did something else. Every really good teacher I had who taught with a passion and the intent to pass on his knowledge and had the courage to go out on a limb to do so had those moments. (Attention deficit moment: ever watch Jacki Chan's bloopers? They are funny as h@!!) I wouldn't consider this failure either as it clearly demonstrate that in a fight you do not get what you want and to have a 'favorite' technique is dangerous. You'll get hit waiting for the perfect moment to execute your favorite technique. So there is a lesson to be learned too.

Now did I ever try to boost my ego, had to show off and demonstrated something really stupid and it went wrong? NO! But I witnessed the most embarrassing moment of that in martial arts history I think. It was an anniversary demo with Sensei and his friends from Okinawa attending at a big celebration with probably close to 1000 people attending from all over the world. Every dojo did a demo and this guy tried a speed breaking demo with 1/4 inch balsa wood not taking into account that there also has to be some weight to the board to pull off a speed break. He had at least 10 boards hung up and didn't break a single one. To add insult, everybody could see how thin the boards were and he did not even pay attention to at least hang the boards so the audience could only see the front of the boards and it didn't show the sides. I ran into him behind stage after his demo and to top it off he had the biggest temper tantrum throwing, hitting and breaking everything in his path and cursing.

As an instructor, NO. As a student, many times.