I think you may be over-reading the results of those studies. My understanding is that most of that research investigates task learning. Those 30-minute sessions aren't developing the broad motor skills involved in martial arts. That's based on what I've seen (looking at studies to better understand adult task learning in business), so it's possible you're looking at something I'm not. If that's the case, probably just ignore what I'm about to write.
If I'm training someone to process checks at a bank, that learning (the physical task) is best developed in small batches. Physical development, however, appears to need more time when combined with skill development and understanding of principles. We can see the faster progress most people make when they attend more than 1-2 classes a week. The same goes for them attending more than one class in a day. See, a class rarely (in my experience) covers only one physical skill at a time. So, take the 30 minutes you came up with, and consider that an ideal time to spend on a new technique (which a class shouldn't be all new material in most cases).
Of course, the bigger issue is that most students won't attend more than twice a week. I've held my classes to 90 minutes (many instructors have shortened theirs) because I don't see people progressing well when they have those shorter classes only twice a week. So you have to balance the two variables (time in topic vs. frequency). I'd rather teach someone three times a week for an hour than twice a week for 90 minutes, but that's not my call to make with most students.
And then you have to factor in some of the hard-to-measure variables. Shorter classes usually (in my experience) leave less time for exploration. The instructor spends 30 minutes on his topic, you lose a bit to warm-up and topic introduction, and a 45 minute class is already done....with the students never getting to play with what they need to explore. This is easiest to see in grappling arts, where some amount of free time is needed for students to tinker with techniques and figure out why some part or principle isn't working right for them.
And that last part leads me back to the problem with private lessons. The instructor has nothing else to do, so he often gets too involved to really let students explore. This isn't an issue if you have a partner and are tinkering outside class, but for the most common students, it can be a problem and can lead to them not learning to think those things through. With the 30-minute private lesson you speak of, the sequence you provide sounds like it might be okay if you're also training with a class or practicing outside those lessons, but 5 minutes of review then 25 minutes of new material doesn't really build skill on its own. It's just not enough time spent on revisiting material. In one lesson, I could teach one or two new techniques (two if they are very related). 5 minutes to review that the next time doesn't give enough repetition to develop skill, and the technique would likely be mostly forgotten by the next class (not enough reinforcement).
Of course, level of experience matters a lot. Even if you're brand new to an art, you still have some skill and understanding from past experience if you've trained before. So when I speak of beginners, I'm talking less about beginners to a new art (although some of what I said applies to them) and more about people getting their first serious adult taste of martial arts.
My reading was definitely in regards to athletic performance and motor skill acquisition in sports. I don't remember all the details because I did most of my research on the topic about 17 years ago and then held on to the parts I found applicable to working with my strength training clients and in my own training. I hope that we've learned some things in the intervening years and this conversation may be the spark that gets me to look at where research has gone.
When I was doing a lot of reading about motor skill acquisition it luckily coincided with my first effort to take a ballroom dance class. I was wondering why I was failing to learn the material when there is a lot of skill overlap between partner dancing and martial arts and I (at least believed) that I had some reasonable aptitude for martial arts. By happenstance at exactly that time I ran across an article by an expert on athletic training that perfectly described my experience (setting aside issues related to skill transfer between similar but non identical activities for the moment). The author cited a number of studies that indicated to me that my problems were likely because my classes were too long and too infrequent for beginners.
So, in my experience, ballroom dance classes run for 60-90 minutes, usually once (
maybe twice) a week and are done as a progressive series. For example, you take Tango 1 before Tango 2 and each class runs for a set period of time (usually 4 weeks, sometimes longer) and progresses through a set curriculum much like a standard college course. If you miss a session you're going to need to "make it up" outside of class with someone or you'll be missing things for the next lesson. Most classes try to cover a lot of vocabulary each class, usually they teach you a new dance move, you practice it for a couple of songs with different partners and then you're on to the next one.
I found that in the first class I was really getting it at first but by the end of the class I was clinging to the material with my finger tips. As the class progressed and there was more and more material that I only sort of understood it got worse and worse. This was true even though I was practicing regularly between classes. After reading the article I mentioned, when I started another dance class I started checking my watch as soon as I started to feel overwhelmed and sure enough it was right about the 30 minute mark (as suggested by the research) that things would start to jumble together in my head.
This seems to hold true for me when I'm a beginner in martial arts classes as well, but it tends to be less pronounced. First, unlike partner dance, most MA classes are ongoing. I think this both masks and somewhat mitigates this issue because it's expected that students will miss classes and that there will be a mix of experience levels in each class. This means that the material is more likely to be presented as if to a new audience or at least to get some review and it's expected that you'll see it repeated in future classes. Second, unlike dance, martial arts classes tend to be more forgiving of imperfect technique and in general it's less obvious for a variety of reasons, both positive and negative. Third, most MA classes tend to throw fewer new techniques at you each class. Finally, having done MA of a lot of different types for ~ 30 years I've probably forgotten what it's like to be a
complete beginner in an MA class.
And then you have to factor in some of the hard-to-measure variables. Shorter classes usually (in my experience) leave less time for exploration. The instructor spends 30 minutes on his topic, you lose a bit to warm-up and topic introduction, and a 45 minute class is already done....with the students never getting to play with what they need to explore. This is easiest to see in grappling arts, where some amount of free time is needed for students to tinker with techniques and figure out why some part or principle isn't working right for them.
For a general class I completely agree with all of this ^^^^. I absolutely agree that it's a non trivial task to create a class format that works for a variety of learning styles, availability, skill levels, etc. and I think it's completely realistic that the best practical results in many instances may be to run 90 minute classes, especially when you've got a wide mix of skill levels among the students and can only run or get people to attend 2 classes a week.
Based on my experience, I think that if I were running a class designed strictly for beginners that 45 minutes to an hour at least 2x/week (3-5 would be better) would be ideal. I'd structure it with a progressive curriculum and make it a set duration - probably ~4-8 weeks. I'd do something like 3 levels intended to be taken as a series with a goal of providing a solid foundation in the art so that they could join an ongoing class with confidence and safety in 3-6 months.
To make this work well students would need to be on time and ready to start. Optimally the students would need to be getting the bulk of their exercise in outside of class. It would probably work best for many students if I were to run a 3 month "strength training and conditioning for MA" class prior to the start of the beginners class.
Assuming an hour, I'd do about 5-15 minutes of warm up, depending on the material I had planned for the given class. I'd follow that with 15-30 minutes of instruction covering 1 or maybe 2 related techniques, and then allow the students to practice what was covered, experiment and ask questions for the remainder of the class. I'd strongly encourage students to do at least one open mat type session to practice with a partner in between each class. I'd probably end up experimenting with repeating each class so that an 8 week class with 2 classes/week would have 4 unique classes and each week would be the same class 2x. This would allow students got more chance to absorb the techniques and prevent someone who has to miss a session or two from getting completely left behind. Some things, like rolls and break falls, might make up the majority of an entire short course.
I'm not trying to suggest that this is practical in the real world, but look at it as an exercise to figure out what I'd like to do so that I can see what parts of that I can do. I like to optimize because I think it's fun and interesting and probably because I don't particularly like being a beginner though I really do like to learn new things. I think that if you can make it easy to start a new MA that more students will stick with it and they'll get better faster than if they're thrown in the deep end from day 1.
And that last part leads me back to the problem with private lessons. The instructor has nothing else to do, so he often gets too involved to really let students explore. This isn't an issue if you have a partner and are tinkering outside class, but for the most common students, it can be a problem and can lead to them not learning to think those things through. With the 30-minute private lesson you speak of, the sequence you provide sounds like it might be okay if you're also training with a class or practicing outside those lessons, but 5 minutes of review then 25 minutes of new material doesn't really build skill on its own. It's just not enough time spent on revisiting material. In one lesson, I could teach one or two new techniques (two if they are very related). 5 minutes to review that the next time doesn't give enough repetition to develop skill, and the technique would likely be mostly forgotten by the next class (not enough reinforcement).
Yes, I agree that 30 minutes probably isn't enough for most people if they're completely new to martial arts and are unable to go to group lessons. It's probably often too short if you aren't able to get some sort of real practice with a partner in outside of the private lessons even if you've got some experience with the art in question. It's definitely too short if you go into it without the desire and ability to focus all of your attention on the class for the entire time you're there. The key part for me with 30 minutes is that it's the absolute longest time that I think should be spent teaching new material to a beginner in a single session. An hour is probably fantastic if you spend 30+ minutes of it just practicing the material you've learned and getting feedback.
I also think that being a proactive partner in one's training rather than a passive receptacle for the instructors knowledge is tremendously valuable. Obviously, this is really hard to do if you are completely new to martial arts as you don't even know what you should really be trying to get from your classes. On the other hand, I feel confident based on your posts and my past experience that if I were in North Carolina and you were available to give me private lessons that we could work together to create a training program that would allow me to pick up NGA very quickly. I believe that we could collaborate to combine your knowledge of the art and teaching with my understanding of what I want to learn and how I best learn to arrive at a very effective format. Not all instructors are open to that sort of experimentation, but I don't need to train with everyone.
When I talk about doing lessons as short as 15 or 20 minutes, my thought is strictly to experiment with how to optimize things for me. My idea is to take as many short classes as I can attend and afford, practice the material from the lesson on my own and in a group class and repeat the material in subsequent private lessons until I've got a good handle on it. If I can find a training partner to try this with me, expanding it to 30 minute lessons for the two of us and then doing a lot of partner training would probably be even better. I'll probably post here and see if anyone is interested when I get to that point.
