I started reading the Breaking Muscle blog and it's been a mixed bag. But then I saw a post on "3 Ways Hot Yoga May Benefit You". I have a strong aversion to "alternative" practices. By definition alternative means that it's not supported by the science. But this post is about some published scientific studies on the potential benefits of hot yoga.
I have no problem with yoga - when it's benefits are accurately described. Yoga can be a perfectly good way to meet the flexibility aspects of a complete physical activity program.
I just get all uppity when people say it's great for everything. (And I get that way when anything is called great for everything.)
Some of you may be wondering why I'm going to go on this rant about one study of hot yoga, when this is supposed to be a HEMA training blog. The point is to demonstrate the skills necessary to be a good consumer of science. To learn appropriate caution when encountering science-y sounding fitness claims on the internet.
So, is Hot Yoga good for Fitness?
Well, this blog post went over one study that looked at strength and cardiovascular measures and another for cardiometabolic risk factors. And both studies are flawed. And the results of both studies are overstated. This is a common problem with reporting on science - the results are overstated, and generalized beyond the scope of the study. Furthermore making strong claims about anything based on one study is bad science.
The basic prescriptions for how to improve strength and cardiovascular ability are based on hundreds of studies. So before it can be claimed that yoga improves other fitness components we should have a good evidence base. Not. Just. One. Study.
Bikram Yoga and Physical Fitness in Healthy Young Adults
This study appeared in the Journal of Strength and Conditioning Research. It's not terrible. But it's results are weak and then exaggerated. The study looked at just 21 people. Well, it started with 32 but 11 dropped out of the hot yoga group. That's a big red flag right there! 50% dropout from only hte experimental group severely effects the outcome of a study. The subjects were divided into two groups: hot yoga and control. The hot yoga group was allocated twice as many people, because they expected a high number of dropouts. So, they knew in advance that there would be a problem and went ahead anyways. Not encouraging.
Why did people dropout? We are told that some had scheduling issues and others were "dissatisfied". Quite a number of studies are published in this field without such high dropout rates from scheduling issues. So I think it's much more likely that half of their experimental group just couldn't take the hot yoga program - which is done with the thermostat set extra high and plenty of humidity to boot.
If only the strong survive your study then that will skew the results towards a positive outcome. We don't end up measuring the people who are struggling.
And since they knew in advance that the program was so hellish that half of the subjects (who are volunteers getting paid to do yoga) would dropout you have to wonder whether or not any benefit is going to be worth it.
The control group was doing no exercise and the subjects were all sedentary to start with. In such a group of people any exercise will show improvement. So comparing four and a half hours of exercise a week to no exercise isn't a test of hot yoga versus other methods. It's a test of whether or not it's better than literally nothing.
So what were the results? Unimpressive. Two strength measures were used: grip strength and isometric deadlift. The grip strength showed no improvement, but there aren't any gripping activities in Bikram so that's not surprising. The other test showed some modest improvement*. But it's an isometric test following an isometric program. It's not going to translate well into real world performance and health measures. Since in the real world you don't just pull on a chain attached to the floor, you move.
* Or it didn't because they used shady statistics. I'm not certain about this. But they used a statistical measure that is not common in this field. And they also reported the common measure, and that one came up negative. However, this other test (group x time point comparison) did show statistical significance. Anytime I see a brand new test I get curious - I asked my stats professor about this. So it seems like the test is legit for this purpose. But did the researchers pick this because the regular test didn't support their hypothesis? I don't know.
Flexibility: They measured two flexibility components, low back/hamstring, with a sit-and-reach; and shoulder flexibility. Unsurprisingly, the yoga training produced substantial increases in the sit-and-reach test. But that measure of flexibility is not well correlated with either performance measures or health/fitness measures (like low back pain). So, who cares if that improved?
They also measured active shoulder range of motion. The test involves laying face down and holding a stick overhead. Then you lift the stick as high off the mat as you can. This measure improved as well. But not by a huge amount. Given some of the postures in Bikram this result is not surprising either.
Body Composition: The changes here were slight to none. And we get to see the researchers use the phrase, "trended towards significance". Ha! Individual p-values do not have a trend. When most of the p-values you get in a category are not significant, then you definitely don't have a trend. This phrase is researcher bunk for, "um, we didn't get a positive result, but, we . . uh . . . almost got one."
So, 4.5 hours of light exercise a week barely beat sitting around for improvements in body composition (weight, waist-to-hip ratio, body fat % and lead body mass) - not exactly surprising. Nor noteworthy. Only one actually significant result out of four tested also smells a bit like a fishing expedition.
Cardiorespiratory: I don't know why the researchers thought that standing still in various poses for 90 minutes would have improved cardiovascular health. Maybe because it was so hot that the heart had to work extra hard to keep the body cooled? Suffice it to say there was no improvement in blood pressure or aerobic capacity.
Why is it so Damned HOT in Here?
Seriously? No attempt is made by the authors to explain why they thought that yoga in a super hot, humid room would be better than regular, comfortable room yoga. And none of the things they measured seemed to be related to the heat. None of the minor benefits that were seen can be attributed to the heat since they were all similar to what you would expect from a regular yoga program.
Why do I care, though? Because hot yoga is an unnecessary risk for heat injury. It's hot enough in that room to mess you up. There's a reason that half people in the program decided not to finish it.
A nice description of the risks is given here, and from the same website to boot.
And, no, hot yoga does not sweat toxins out of the body! That's just not a thing. Human physiology doesn't work that way. Sweat glands only selectively excrete specific substances - they don't sieve your bloodstream and leak out whatever they find.
Higher risk than regular yoga or exercise.
Minimal benefits that can just as easily be achieved cheaper and comfier.
Conclusion: not worth it.
But why did I rip so hard into this one study? Because proper science means that the more outlandish the claim the better the evidence required. Saying that a single exercise mode will help everything while in an excessively hot room is an extraordinary claim. So it requires extraordinary evidence. This study fails to meet that bar.
Tracy, B. L., & Hart, C. E. F. (2013). Bikram Yoga Training and Physical Fitness in Healthy Young Adults: Journal of Strength and Conditioning Research, 27(3), 822–830. doi:10.1519/JSC.0b013e31825c340f
Yoga for Cardiovascular Risk
The same blog entry also talks about a study looking at cardiometabolic risk factors. That is risk for heart attacks, strokes and diabetes.
You've got to be kidding me. Light intensity exercise like this has no plausible mechanism for improving any of the things they measured.
And this can't be taken seriously. We can see that with information contained within the citation alone. It's from the Journal of Alternative and Complementary Medicine, which makes the Quackwatch list of Non-recommended Periodicals. This journal has an impact factor of 1.5 which means that most scientists won't cite stuff from it. Neither of these pieces of information is perfect in determining quality, but they show a trend.
The actual study continues the trend.
No control group. Seriously, this journal published a study without a control group. Why?
A large number of disparate measures are used. I feel like they just used everything they had in their lab.
Paradoxical results. One group improved in one measure the other group did not. But the other group improved in something else, unrelated, which the first group also did not improve.
This is not a good study. It should be ignored. Instead of cherry-picking weak studies that show what you want if you squint, the blogger should have looked for good research and clear patterns in the literature.
Yoga for Mental Health
There was one other study in the blog post that I'm ripping on. It was on mental health improvements. However, that exercise and a meditative practice improved some mental measures is not noteworthy. Of course it did. And that's a good thing. If you want to do yoga for the meditative aspect then more power to you.
We have three weak studies of hot yoga. None of them even attempts to address the core issue: does hot yoga have any benefit over regular yoga? Read any text on exercise, personal training, sports medicine etc. and you will have a section on how high heat and humidity is dangerous. How training in those conditions should be avoided, and when it can't be avoided you have to take additional precautions to keep people safe. 90 minutes straight of activity in that heat would not be considered safe in any other context.
Only in alternative practices would this even be considered. Take something known to be dangerous and then declare it superior. Then don't bother testing it. Remember, none of these studies compared regular temperature yoga to hot yoga.
This is the kind of research that's considered good enough for alternative medicine. And it's why these kinds of claims must be scrutinized more closely.
Continuing to talk about how to improve the healthcare system (like I did here) there is another clear place for primary care to improve - exercise and fitness advice at the doctor's office.
Too many times I have had friends complain, legitimately, that the doctor just tells them to get more exercise and says nothing more about the topic. They just hope that this is enough. Or maybe there is a pamphlet.
Exercise is too big a topic for most people to just jump right in because their doctor said so. And those who do are quite likely to overdo it, injure themselves and then stop exercising because last time they got hurt. (Commonly this is thinking that you have to do 30 minutes of cardio as a minimum; which is too much as a starting point for most folks - I talk more about this here.)
Furthermore, most doctor's don't know what's involved in a complete approach to physical activity for health. Doing a lot of running, without any kind of strength training can cause injury and does little for some of the common problems of aging like muscle loss and osteoporosis. As I've said before, I don't fault the doctor's for not knowing everything. But it is a reason for primary care to have some fitness and/or PT component attached.
What people need is someone who can guide them through getting started with an exercise program. Doctors' offices are already incorporating dietitian's to provide nutrition advice, so let's add the other half of healthy living: physical activity.
The emphasis of such a program should be on behavior change. A topic well-covered in my undergrad program. Basic exercise advice is easy. Helping a person make long-term changes to their life is different. It requires a different skill set. It takes a lot more than just a personal trainer certification.
UMass Boston's major in Exercise & Health Sciences has a mandatory track of classes in behavior change. Graduates from this program would be the ideal kind of person to add to the staff at a doctor's office. Because this person doesn't get paid like an MD they can spend more time with each patient. They would be dedicated to just one topic when they meet with the patient, unlike an MD doing a physical which has to cover every organ system of the body.
I'm going to see what I can do about just this as part of my time at the Institute of Health Professions. Health promotion and community outreach is a part of our the program at IHP. Perhaps I'll get to run a small pilot program. I don't know.
The approaches I commonly see for training 'balance' for HEMA are a problem. The problem is lack of specificity. Single-leg balance and yoga poses are encouraged. Long holds in various stances are recommended. Even things like wobble boards and BOSU's sometime are suggested.
Don't Do This!
(updated when this topic came up on the HEMA Alliance forum)
These all fail to be good choices for a simple reason: they are based on the idea that balance is a singular trait that you can improve. Like your Dexterity score in D&D. The human body just doesn't work that way. Our wires are not set-up that way.
Balance is always task specific. The best programs for preventing falls in the elderly aren't yoga and single-leg standing. They are obstacle courses. Walk and deal with obstacles - 6 inch high hurdles and the like in this situation - and that makes a person less likely to fall while walking.
Avoiding falling is also about power. When you are off-balance it does not take a 30 second sustained low-intensity contraction to right yourself. It takes a brief high-intensity action. And this is another way that strength training benefits HEMA and long-term human health and wellness.
And in HEMA the kinds of situations that lead to falls are when you are almost always when you are moving and moving fast.
So really, balance for HEMA is agility training.
I write this now because of a recent post over at the HEMAists. But I'm not picking on them. There is good stuff there too, just scroll down to see the part I liked. I've encountered similar suggestions in many places.
One guy on the Alliance forum FB page suggested holding a lunge position with arms extended out to the side for 60 seconds. He said I should try it to see how hard it is. But how hard that would be is irrelevant. In fencing I will never hold the end of a lunge that long. And the difference is an order of magnitude. And I'll never hold my arms out to the side that long either.
So the fact that it is hard tells us nothing about whether or not it is relevant to fighting. These are separate characteristics being measured.
How do we train 'balance' for HEMA?
We do it with agility drills. Exercises like ladder (or sword) drills, dots, cones, rings and hurdles. (Nah, I don't get any money from these folks. I just like their products (however their are frequently cheaper options available.))
I'll be talking about agility drills some more in the next few weeks. And I've talked about it a bit before.
Balance v. Stability
Balance and stability don't mean the same thing. This is me being pedantic because I'm professionally a nerd on this topic. But I think the difference is relevant and I'll provide an example in a moment.
In exercise science we use the terms to mean:
Balance - keeping the whole body upright or in position
Stability - a characteristic of an individual joint being capable of holding a position
I'm not thrilled with the balance exercises from that HEMAists article. But I do like the stability exercises at the bottom. The exercise is a plank with a punch out, then rotate to a side plank and punch up. This exercise doesn't train balance. It trains maintaining a stable spine while moving around it. It's another way to do dynamic core work. I'm starting my guys on this exercise tomorrow.
I would make one addition about the exercise as described. An easier version is to start with the down arm on the elbow. A lot of people will need to start there.
Think hard about what specificity means before adding in new, neat exercises.
P.S. I've got a sale going on right now for in-person training.
Hey everybody, my semester has finally wound down enough for me to have spare brainpower. I had 19 credits in 8 classes. 17 hours of lecture, 9 hours of lab and 4 hours of clinical. Plus all the reading and studying necessary to absorb that much information. It was intense. But I do truly love my course material.
This post is not on-topic for this blog. Well, not obviously on topic. But I want to write about this topic anyways because it's a big part of what I want from my schooling and how I think I can improve the healthcare system. Big stuff.
I have this hypothesis. The hypothesis is that if a consult with a physical therapist was a part of the regular physical then we could improve health outcomes over the long-term. Right now, almost all PT is treatment. There is almost no component of screening or prevention. The stuff I write about strength training and physical activity for wellness are more prevention work than most PT's can do.
Our national profession organization, the APTA, my professors and others in the field are all well aware of this limitation. And their is a desire to improve the situation. That's part of why the switch to doctorates and self-referral are important to the future of the profession.
This Canadian physical therapist elaborates nicely on the topic. If, as a part of every physical, you had an expert who checked out your posture and your gait (the way you walk) then hopefully we can spot problems while they can still be prevented. This consult could also include talking about workplace ergonomics since that will have a huge impact on a person's body over time.
Preventing even a small percentage of low back pain cases would be huge. Low back pain is the most common cause of missed work and represents a huge drain on people's lives and the economy. Physicals weren't called annual check-ups where I worked, when I worked for a PCP. How often you needed a full health review was based on age and specific health conditions - health 20-somethings were only expected to get a physical every five years. Part of the experiment and study needed to validate my hypothesis would be figuring out how often makes sense, both from a health standpoint and an economic standpoint. I'm not certain that this kind of screening and prevention will pan out to work well. But it seems likely. So I want to find out.
Recently, I ran a class at Iron Gate Exhibition (IGX) on the topic of Speed & Agility. I co-taught the class with Dakao Do of Schwert am Schwert of Houston, Texas. Below is the class description and the outline of the class.
I'm going to flesh out the outline a bit, but I actually ran the class with just a sketch. Not only that but the first time that Dakao and I got to talk in-person about the material was just Thursday night, for a Saturday morning class. And in-between we were both very busy with running IGX. We had talked on the phone about a month before, but this is all movement related stuff, so there's a limit to what you can make clear over the phone.
Additionally, there was some stuff that I'd planned to discuss but did not get to (there's never enough time).
Suffice it to say it was a bit of an adventure. But the whole weekend was, so that's par for the course.
Structure and Motion
Fast, maneuverable footwork is an essential component of historical fencing and martial arts. Correct skeletal alignment is the structural foundation on which safe, strong, fast fencing and fighting are based. Structure is present in all guard stances, movements, and strikes. This class will teach some fundamental principles of leverage for control, power, and safety in the fight. Building on that foundation, we will cover a variety of drills designed to improve footwork through the principles of overload, permutational analysis, and body awareness (proprioception). Simple (and cheap) tools such as ladders and cones will be demonstrated to provide drills to bring home to your club. High-intensity interval training for speed and cardio conditioning will also be covered.
Training Power - appropriate reps and rest are required to train power
Permutational Analysis - underlying theory for highly varied footwork training
Proprioception - many training tools and methods described here are intended to provide proprioceptive feedback
Space - sometimes that's all you need
Dots/Cones - I prefer dots over cones for many drills since you can step on dots, and thereby use them to require precise footwork and this is a mechanism of proprioceptive feedback
The class was organized like an extended training session.
Ladder - Ladder drills should include 5-6 activities
More on ladder drills will be included in later posts
Lateral & Diagonal
The hip, knee and ankle should be in a straight line for efficient transmission plus joint safety
Change of Direction (cones/dots)
Lateral W and Sprint
L and +
longsword circle drill, with 10 variables
Speed & Acceleration
60m suicide sprint
This is just a taste of what was in the full-class and many of these topics will be filled out later.