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Autor: markyoung
~ 20/04/10
A while back I wrote an article on a variety of things that people should concern themselves with when reading and reporting on scientific studies. As it turns out, it was very well received so I’ve decided to follow up with another post in which I’ll try to highlight some other important considerations when reading a scientific papers.
To illustrate my points I’ll be highlighting a couple of papers as well so you might pick up some bonus learning along the way.
That Sure is ACUTE Study
One thing that is important to take into consideration is whether the study you’re looking at is an acute study or a chronic (i.e., training) study. For example, researchers at McMaster wanted to determine whether soy protein or milk would provide greater muscle gains. Previous research had suggested that soy proteins may be used more for splanchnic (intestinal) metabolism to a greater extent than milk so they decided to see if milk could stimulate more protein synthesis after training.
In an early study they had each participant in the study perform a standard leg workout involving leg press, leg extensions, and leg curls, drink either the milk or soy beverage, and follow up with muscle biopsies, arterial and venous blood samples. The subjects would also have them come back on another day to repeat the study with the other beverage. (Note that the study protocol is much more involved, but I’m simplifying for the sake of brevity)
After all measures were taken the net protein balance area under the curve(i.e., muscle growth) was statistically greater in the milk condition than the soy condition. In fact, this measure was almost double that of soy. This is an example of an acute study.
Clinical Significance
So after all that work, and prodding, and poking what does that study actually tell the trainee in the trenches trying to put on muscle mass? How much more muscle could they expect to gain using milk versus soy? The truth is, we just don’t know. And THAT is the difference between statistical significance (i.e., the results weren’t just due to chance) and clinical significance (results that we can actually apply to practice).
So, to take the results to the real world the McMaster group repeated the study again except that this time they trained three different groups with a split routine on 5 days per week for a period of 12 weeks. Each group either received the soy protein, milk, or a placebo beverage (actually just carbs) and results for muscle and fat mass were measured over the 12 weeks.
In the end, muscle mass gains were as follows:
The placebo group gained 5.3 lbs
The soy group gained 6.2 lbs
The milk group gained 8.6 lbs
Statistically speaking, the milk group was better than both soy and placebo, but soy was not superior to the placebo. These results are also clinically significant. In other words, they are actually applicable. This is an example of a longer term study as opposed to an acute study.
Variability
Since the study above shows milk to be superior I figured that now would be a good time to demonstrate the importance variability between subjects. The dotted line on this graph represents the median amount of muscle gained across all groups. As you can see, those in the milk condition easily gained the most. But within that group you’ll notice that there were those who gained only 2 kilograms (4.4 pounds) of muscle and others who gained almost 7 kilograms (15.4 pounds). In fact, there was one person in the soy group who gained more muscle than anyone in the milk group! Taken as a whole, this study indicates that milk is superior to soy for muscle gain when taken post workout, but always remember that within every study there is variability. Statistically speaking, you are most likely to fall close to the average, but there is always a remote possibility that you are one of the outliers. If you’re using a system that seems to be working for others and it isn’t working for you, this might be the reason.
But now you might be wondering why on earth the didn’t just do this study instead of taking time with the shorter study first. Well, the main reason is that large training studies take a LOT of time and money. They also require a huge amount of manpower to recruit, train, and test all the subjects. At least with an acute study the trial is fairly short and less labour intensive so you can test your hypothesis up front to get an indication of the results to follow. These results can also be used to solicit funding for the longer term project and to justify the use of resources. After all, it would be a giant waste of money and resources if you ran a lengthy training study only to find out that your hypothesis was wrong.
All in all, there are many elements of a research study that can be subject to consideration and I hope I’ve provided you with a snapshot into the world of reading the science.
Feel free to leave your thoughts and comments below!
Awesome Mark!
Comment by Bret Contreras — April 20, 2010 @ 4:15 PM
Hey, Mark. Great stuff here!
Since you don’t pull any punches, I wanted to throw out an idea for a future post, since this seemed like one of the easiest places to reach you.
These days a lot of trainers attempt to put out products, and some (even some who are supposedly regarded as very reputable by various people in the industry)are known primarily as internet marketers, even if they have or still do work with folks in the real world at times.
On the one hand, it seems like a blatant money grab (see guys who seems to release a new fat-loss program every time you blink. But on the other hand, it’s hard to knock anybody for trying to get ahead financially, so long as they’re not entirely fleecing the unsuspecting masses.
I’m left feeling torn, because it doesn’t do much financial good to want to put out such a high-quality product that you either get held up entirely or take an exceedingly long time to complete a project, but on the other hand, I have to wonder when people, even when niche-specific marketing is touted as where it’s at, are always releasing products and programs that are all about the same basic thing (I mean if your last fat-loss product was such dynamite stuff to warrant big sales, why, other than to pad the bottom line, would another one be needed so soon after? Yes, we refine our methods over time, but that rarely warrants entirely different products, at least not in my book, and the major refining usually happens over years, not a few short months)
Of course to the guy who can rake in a big financial haul in a few shorts days with a big release, it seems elementary to want to do this, since no one is being overtly scammed. In fact, he’d probably call any trainer who has mixed feelings about this stuff a sucker.
So for this question I am basically asking your thoughts on the “gray” area where you have guys who aren’t inherently unethical and have some decent information to share but are often the beneficiary of having built a list (more power to them for making the effort on that front) that will buy almost anything they release, regardless of how truly innovative it is relative to any previous releases. There are probably quite a few well-known guys in this industry who have the knowledge and ability to release one excellent product, build a solid list, and then flip on cruise control while regularly churning out decent stuff in minimal time. While it would represent far less than their absolute best, their dedicated list would still willingly scoop up whatever they offered. And yet many of these guys who could do this don’t do so.
But I suppose the question becomes if you could sell it and add to your financial security, is it truly worthwhile to be hyperconcerned about “selling out?” At the end of the day, I suppose there’s nothing noble about passing up potential revenue streams simply out of a case of being a perfectionist. And while people often talk about being great at what you do first and having a passion for it, this doesn’t automatically equate to financial success, and exception don’t prove the rule. For every guy who is excellent at his craft, busts his hump, and does quite well, there are likely a handful of similar guys who can barely make ends meet.
Comment by Ray Maluga — April 20, 2010 @ 4:53 PM
Keep this up Mark:
There is way too much continuing education from illegitimate or “un”credentialed sources these days…especially with the newer forms of social media.
I just wish more professionals would understand what it really takes to READ research. Its not about abstracts and conclusions folks.
READ THE METHODS!!!
Comment by Jeff Cubos — April 20, 2010 @ 5:19 PM
What do you mean by, “it would be a giant waste of money and resources if you ran a lengthy training study and only to find that your hypothesis was wrong?” Whether your hypothesis is right or wrong, either way you learn something. No?
Comment by Neal W. — April 20, 2010 @ 6:04 PM
Holy hell, man.
Thank you for talking about this. I work in research and I have had to explain exactly what you said here countless times. Now I can just link to this page!
Thanks!
Comment by Robert — April 20, 2010 @ 6:26 PM
to Neal W:
one correction to what Mark says above: it is important to do the smaller studies not necessarily to do a preliminary test of your hypothesis, but to work out protocol bugs and to also demonstrate to granting agencies that you are capable of doing what you set out to do e.g. that you have the analytical skills, infrastructure, ability to recruit, ability to retain people in the study etc.
it is a bad idea to do the smaller studies to preliminarily test your hypothesis because you could conclude that it is wrong when it is actually right (or vice versa), because your sample size was too small to detect a difference, or your methods were not quite right, or the effect is chronic but not seen in an acute study etc.
Comment by lora — April 20, 2010 @ 7:35 PM
@ Bret – Thanks brother.
@ Ray – I’ll definitely write a blog post on this soon. Great topic!
@ Jeff – Amen. Methods and Stats. Without them conclusions mean nothing.
@ Robert – Glad I could be of help. Link away my friend!
@ Neal – Generally speaking if your study fails to show an effect it is sometimes harder to get it published. Despite the fact that you’ve learned something, scientific careers are often built on the number and quality of publications you’ve had. And Lora (who is actually a very bright PhD) makes a good point about not resting too much on the conclusions of acute trials.
Comment by markyoung — April 21, 2010 @ 10:23 AM
Ray – have you read this? http://bretcontreras.wordpress.com/2010/03/23/perspective-in-the-fitness-business-by-sam-leahey/
Mark – another awesome post man. I LOVE when you talk about research implications, as i’d like to think i am one who draws alot of his information from research. Not only that but i’ll be doing my thesis soon so this information really put me ahead of the game. Thirdly, its so easy to just read the abstract and conclusions so i think it’s great that big timers like you are here to keep us all in check! Keep up the good work man!
Comment by Sam Leahey — April 22, 2010 @ 7:03 AM
Thanks Sam! Appreciate the comment.
Comment by markyoung — April 22, 2010 @ 4:06 PM
[...] My friend Mark Young has recently posted a great piece about how to read the literature. Check it out. It’s more than abstracts and [...]
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