The mysteries of Placebo and The Placebo Effect

I'm currently mid-way through a book titled 'Placebo' by Dylan Evans, which is excellent. I recently read '13 Things that don't make sense' by Michael Brooks (which I would absolutely recommend!) which had a section on the placebo effect, and which prompted me to want to read and learn more about it.

This is going to be a short blog post because I am unclear where I stand on the subject and like I said I am only half way through the book. But there is a couple of specific studies that I really felt the need to pass on.

Valium
Valium (diazepam) is sold by the billions and is used for treating anxiety, insomnia, seizures, muscle spasms, alcohol withdrawal, and more. It is considered a 'core medicine' and is on the World Health Organisation's "Essential Drugs List"! It is marketed in over 500 brand products throughout the world, and since it's invention and approval for use in 1960 was the top-selling pharmaceutical in the USA from 1969 to 1982, with peak sales in 1978 of 2.3 billion tablets. You can imagine the financial figures both in expense to consumer and government figures run in to the billions of £'s and $'s every year.

You might have known all this, or have been able to guess it. What you probably didn't know is that according to all of the clinical research Valium only works if you know you're taking it. That is, if you are given it without knowing what it is and what it does, then it doesn't really work.

Morphine
This is a little more complicated but (to me) doubly interesting. Jon Levine and Howard Fields published a study in 1978 in the Lancet reporting placebo effects of pain reduction on post-operative patients. They were given a saline solution and told it was morphine. As by now you've guessed; they reported significantly reduced pain when given the medication. Nothing too exciting...yet. They were then given Naloxone which works by blocking the same receptor sites in the brain which morphine molecules attach themselves to. E.g. it works to block morphine. However, the patients weren't told they were being given this, and to add to it they weren't even being given morphine. No matter, they reported significant increases in pain again.

So what is going on here? Well the theory behind all of this goes that when told that they were being given morphine their body released endorphins which were similar enough to morphine and effected the body in the same way at the same sites. [Super interesting fact that I didn't know: the term endorphin is derived from endogenous morphine!] And thus endorphins were acting to reduce the pain, and then when the patient was given Naloxone it blocked these endorphins. Great.

Of course, this doesn't answer why the pituitary started producing endorphins when given a saline solution and told they were given morphine. And it doesn't answer why the body didn't start producing the endorphins early when the body was obviously in pain.

Reality, sometimes books (and now blogs) leave you with more questions than you started with!

As I learn more in this area I'll be sure to pass it on.

Be well

J

Resistance Load does not affect Strength gains: Fact

Let me initially start by apologizing for how long it's been since my last blog; I've been away with GB Women's Wheelchair Basketball to Canada where the team picked up some more hardware. This time a Bronze medal in the Under 25 World Championships! Well done ladies!!

As for the current blog, well it's a topical area and likely something that no matter how much evidence is presented on the subject will probably not change the perspectives of many resistance training individuals. That said; I'm a scientist, and I present the science, it's then your choice to act upon it or ignore it.

Over a year back now I started writing a thorough review article on Evidence Based Resistance Training (it's hopefully going to print later this year). It's origins lie further back than that, in a manuscript I once wrote gathering all the knowledge I'd acquired into one place. Ultimately it questions a lot of the advice surrounding the American College of Sports Medicine's (ACSM) Position Stand on Resistance Training, and provides more scientific guidelines.

Size Principle
A key reference at the time of writing, and a journal article I would wholeheartedly recommend is "The Size Principle, and a Critical Analysis of the Heavier-is-Better recommendation for Resistance Training" by Ralph Carpinelli (follow link for full text pdf). In essence the article discusses the misnomer that lifting heavier weights makes you stronger. Yes, you read that right. Lifting heavier weights does not make you stronger. In fact the evidence suggests that it is not the load lifted, but that you lift to muscular failure (until you can lift it no more).

In simple terms our muscles are made up of different muscle fibers some are faster twitch which means they fatigue faster, and some are slower twitch which means they fatigue slower. Whilst there are generally considered distinct muscle fiber-types, I normally teach it on a spectrum of fast to slow twitch. The fastest being capable of producing greatest force but fatiguing first and taking longer to recover and the slowest producing least force, fatiguing last and recovering very quickly. Well due to the 'all-or-none' principle, if we recruit a muscle fiber we recruit it completely....but we only use what we need, e.g. if I pick up a pen I do not recruit all the fibers in my arm to do this, I recruit only what I need to perform the task, but I recruit those fibers to exhaustion. In this case very few of them,  and dominantly slow twitch because they will recover quickest. (Our body reserves the use of fast twitch fibers for stressful situations. - In Paleolithic times this could best be described as either catching prey or avoiding being prey!!). If I lift a heavier weight I might need to recruit more slow twitch fibers, or if heavier still; then fast twitch muscle fibers as well.

So if we select a weight to lift then we will recruit the muscle fibers required to lift the weight, if we perform a second repetition then we will likely need to recruit more muscle fibers since some of those used in the initial repetition will not have recovered. And so forth. This simple principle suggests that it doesn't matter what weight we lift, and thus how many repetitions we perform, only that we lift a weight until we can lift it no more (with proper form).

Sure enough the scientific evidence supports this. In fact, a more recent article "The Correct Interpretation of the Size Principle and it's Practical Application to Resistance Training" by Sandee Jungblut (follow link for pdf) cites 90 research article, of which 82 found no difference in strength gains relating to load used. E.g. it didn't matter what weight they lifted or how many repetitions they performed, strength gains were the same. Interestingly the article also comments that of the 8 studies that did find a difference, 7 of them were with previously untrained participants.

Strength, Hypertrophy and Muscular Endurance
I find this an interesting area since many associations, magazines, trainers and general gym goers often periodize their training for strength, hypertrophy, muscular endurance, etc. When in reality training to muscular failure optimizes strength. Indeed, training to muscular failure also seems to optimize growth gains. And if we get stronger then we are generally able to lift the previous weight more times (enhancing muscular endurance). Thus the varying of load and repetitions seems to be purely for psychological reasons without physiological effect.

On a secondary note, many persons are under the impression that moving a lighter weight quickly will force the body to recruit fast twitch muscle fibers, and make a person faster. Once again a common misnomer without any evidence to support the hypothesis.

Summary
All of this said, there is another factor which is sometimes overlooked; that of other health gains. It should be clarified that the evidence suggests that a weight needs to be 80% 1RM or greater to enhance the bone mineral density of the participant. Undoubtedly there will be contradictory research, and without having thoroughly reviewed this area I am not in a position to comment, except to say that to cover all bases optimal repetition ranges likely cause muscular failure (the inability to complete any more repetitions) at somewhere between 8 and 12 repetitions for most exercises.

I raise this issue for two main reasons: the first of which is to help those already training to better understand their bodies and how to train, and the second of which is to let people who do not currently do any resistance training that you don't have to lift heavy weights!!

On a side note (and since I'm in for a penny; in for a pound!) - lifting with a more reasonable resistance (rather than a resistance you can only lift once or twice) will allow you to maintain better form throughout the exercise. After all the emphasis here is not to move the weight, but to contract the muscle. Moving the weight is simply a by-product. We would all do well to remember this.

Be well. Train Hard.

J