You can eat a lot during the Holiday Season and gain no body fat, as long as you also eat little

This post has been revised and re-published. The original comments are preserved below. Typically this is done with posts that attract many visits at the time they are published, and whose topics become particularly relevant or need to be re-addressed at a later date.

Dried mussels: A little plate with 160 g of protein (plus some comments on high-protein low-carbohydrate dieting)

Many hunter-gatherer groups employed various methods of drying to preserve meats. Drying also increases significantly the protein content of meats; this is the case with dried mussels. I discussed this effect of drying before here with respect to small fish (). The photo below is of a plate with about 240 g of dried mussels that I prepared using the simple recipe below.



To prepare your mussels as in the photo above, you will have to steam and then dry them. You can season the mussels after you steam them, but I rarely season mine. Almost none of the food I eat requires much seasoning anyway, because I use nature’s super-spice, which makes everything that has a high nutrient content taste delicious: hunger ().

- Steam the mussels for about 10 minutes, or until all are open.
- Remove the mussels from the shells; carefully, to avoid small shell pieces from coming off into the mussels (they are not kind to your teeth).
- Preheat the oven to about 200 degrees Fahrenheit, and place the mussels in it (on a tray) for about 1 hour.
- Leave the mussels in the oven until they are cold, this will dry them further.

About 240 g of mussels, after drying, will yield a meal with a bit more than 160 g of protein – i.e., the proportion of protein will go from about 20 percent up to about 67 percent. In this case, most of the calories in the meal will come from the protein, if you had nothing else with it, adding up to less than 800 calories.

This comes in handy if you need to have lunch out, as the dried mussels can be carried in a plastic bag or container and eaten cold or after a light re-heating in a microwave. To me, they taste very good either way; but then again anything that is nutritious tends to taste very good when you are hungry, and I rarely have breakfast. I often eat them with pre-cooked sweet potato, which I eat with the skin (it tastes like candy).

You may want to think of dried mussels prepared in this way as a protein supplement, but a very nutritious one. You will be getting a large dose of omega-3 fats (3.11 g) with less omega-6 fats than you usually get through fish oil softgels (where n-6s are added for stability), about 1,224 percent of the recommended daily value (RDV) of magnesium, 461 percent of the RDV of selenium, 1,440 of the RDV of vitamin B12, a large dose of zinc, and (interestingly) almost 100 percent of the RDV of vitamin C.

Since mussels are very low in the food chain, accumulation of compounds that can be toxic to humans is not amplified by biomagnification (). But, still, mussels can be significantly affected by contaminants (e.g., petroleum hydrocarbons), so sourcing is important. The supermarket chain I use here in Texas, HEB, claims to do very careful sourcing. Telltale signs of contamination are developmental problems such as thin shells that shatter easily and stunted growth ().

For those readers who are on a low-carbohydrate diet, please pay attention to this: there is NO WAY your body will turn protein into fat if you are on a low-carbohydrate diet, unless you have a serious metabolic disorder (see this post: , and this podcast: ). And I mean SERIOUS; probably way beyond prediabetes. Do not believe the nonsense that has been circulating in some areas of the blogosphere lately.

A high-protein low-carbohydrate diet is one of the most effective diets at reducing body fat, particularly if you do resistance exercise (and you do not have to do it like a bodybuilder). That is not to say that a high-fat low-protein diet (like the "optimal diet") is a bad idea; in fact, the optimal diet is a good option if you do not do resistance exercise, but that is a topic for a different post.

Latitude and cancer rates in US states: Aaron Blaisdell’s intuition confirmed

In the comments section of my previous post on cancer rates in the US states () my friend Aaron Blaisdell noted that: …comparing states that are roughly comparable in terms of number of seniors per 1000 individuals, latitude appears to have the largest effect on rates of cancer.

Good point, so I collected data on the latitudes of US states, built a more complex model (with several multivariate controls), and analyzed it with WarpPLS 4.0 ().

The coefficient of association for the effect of latitude on cancer rates (path coefficient) turned out to be 0.35. Its P value was lower than 0.001, meaning that the probability that this is a false positive is less than a tenth of a percent, or that we can be 99.9 percent confident that this is not a false positive.

This was calculated controlling for the: (a) proportion of seniors in the population (population age); (b) proportion of obese individuals in the population (obesity rates); and (c) the possible moderating effect of latitude on the effect of population age on cancer rates. The graph below shows this multivariate-adjusted association.



What is cool about a multivariate analysis is that you can control for certain effects. For example, since we are controlling for proportion of seniors in the population (population age), the fact that we have a state with a very low proportion of seniors (Alaska) does not tilt the effect toward that outlier as much as it would if we had not controlled for the proportion of seniors. This is a mathematical property that is difficult to grasp, but that makes multivariate adjustment such a powerful technique.

I should note that the 99.9 percent confidence mentioned above refers to the coefficient of association. That is, we are quite confident that the coefficient of association is not zero; that is it. The P value does not support the hypothesized direction of causality (latitude -> cancer) or exclude the possibility of a major confounder causing the effect.

Nonetheless, among the newest features of WarpPLS 4.0 (still a beta version) are several causality assessment coefficients: path-correlation signs, R-squared contributions, path-correlation ratios, path-correlation differences, Warp2 bivariate causal direction ratios, Warp2 bivariate causal direction differences, Warp3 bivariate causal direction ratios, and Warp3 bivariate causal direction differences. Without going into a lot of technical detail, which you can get from the User Manual () without even having to install the software, I can tell you that all of these causality assessment coefficients support the hypothesized direction of causality.

Also, while we cannot exclude the possibility of a major confounder causing the effect, we included two possible confounders in the analysis and controlled for their effects. They were the proportion of seniors in the population (population age) and the proportion of obese individuals in the population (obesity rates).

Having said all of the above, I should also say that the effect is similar in magnitude to the effect of population age on cancer rates, which I discussed in the previous post linked above. That is, it is not the type of effect that would be clearly noticeable in a person’s normal life.

Sunlight exposure? Maybe.

We do know that our body naturally produces as much as 10,000 IU of vitamin D based on a few minutes of sun exposure when the sun is high (). Getting that much vitamin D from dietary sources is very difficult, even after “fortification”.

Aging and cancer: The importance of taking a hard look at the numbers

The table below is from a study by Hayat and colleagues (). It illustrates one common trend regarding cancer – it increases dramatically in incidence among those who are older. With some exceptions, such as Hodgkin's lymphoma, there is a significant increase in risk particularly after 50 years of age.



So I decided to get state data from the US Census web site (), on the percentage of seniors (age 65 or older) by state and cancer diagnoses per 1,000 people. I was able to get some recent data, for 2011.

I analyzed the data with WarpPLS (version 4.0 has been just released: ), generating the types of coefficients that would normally be reported by researchers who wanted to make an effect appear very strong.

In this case, the effect would be essentially of population aging on cancer incidence (assessed indirectly), summarized in the graph below. The graph was generated by WarpPLS. The scales are standardized, and so are the coefficients of association in the two segments shown. As you can see, the coefficients of association increase as we move along the horizontal scale, because this is a nonlinear relationship. The overall coefficient of association, which is a weighted average of the two betas shown, is 0.84. The probability that this is a false positive is less than 1 percent.



A beta coefficient of 0.84 essentially means that a 1 standard deviation variation in the percentage of seniors in a state is associated with an overall 84 percent increase in cancer diagnoses, taking the standardized unit of the number of cancer diagnoses as the baseline. This sounds very strong and would usually be presented as an enormous effect. Since the standard deviation for the percentage of seniors in various states is 1.67, one could say that for each 1.67 increment in the percentage of seniors in a state the number of cancer diagnoses goes up by 84 percent.

Effects expressed in percentages can sometimes give a very misleading picture. For example, let us consider an increase in mortality due to a disease from 1 to 2 cases for each 1 million people. This essentially is a 100 percent increase! Moreover, the closer the baseline is from zero, the more impressive the effect becomes, since the percentage increase is calculated by dividing the increment by the baseline number. As the baseline number approaches zero, the percentage increase from the baseline approaches infinity.

Now let us take a look at the graph below, also generated by WarpPLS. Here the scales are unstandardized, which means that they refer to the original measures in their respective original scales. (Standardization makes the variables dimensionless, which is sometimes useful when the original measurement scales are not comparable – e.g., dollars vs. meters.) As you can see here, the number of cancer diagnoses per 1,000 people goes from a low of 3.74 in Utah to a high of 6.64 in Maine.



One may be tempted to explain the increase in cancer diagnoses that we see on this graph based on various factors (e.g., lifestyle), but the percentage of seniors in a state seems like a very good and reasonable predictor. You may say: This is very depressing. You may be even more depressed if I tell you that controlling for state obesity rates does not change this picture at all.

But look at what these numbers really mean. What we see here is an increase in cancer diagnoses per 1,000 people of less than 3. In other words, there is a minute increase of less than 3 diagnoses for each group of 1,000 people considered. It certainly feels terrible if you are one of the 3 diagnosed, but it is still a minute increase.

Also note that one of the scales, for diagnoses, refers to increments of 1 in 1,000; while the other, for seniors, refers to increments of 1 in 100. This leads to an interesting effect. If you move from Alaska to Florida you will see a significant increase in the number of seniors around, as the difference in the percentage of seniors between these two states is about 10. However, the difference in the number of cancer diagnoses will not be even close to the difference in the presence of seniors.

The situation above is very common in medical research. An effect that is fundamentally tiny is stated in such a way that the general public has the impression that the effect is enormous. Often the reason is not to promote a drug, but to attract media attention to a research group or organization.

When you look at the actual numbers, the magnitude of the effect is such that it would go unnoticed in real life. By real life I mean: John, since we moved from Alaska to Maine I have been seeing a lot more people of my age being diagnosed with cancer. An effect of the order of 3 in 1,000 would not normally be noticed in real life by someone whose immediate circle of regular acquaintances included fewer than 333 people (about 1,000 divided by 3).

But thanks to Facebook, things are changing … to be fair, the traditional news media (particularly television) tends to increase perceived effects a lot more than social media, often in a very stressful way.

The sub-2 hour marathon? Don't hold your breath, just yet

Is the sub-2 hour marathon imminent?  Don't hold your breath

Yesterday Wilson Kipsang took 15 seconds off the marathon world record, running 2:03:23.  It triggered, as it always does, talk of how close they are to breaking the two-hour barrier.  But that's very, very premature.  For reasons of physiology, performance evolution, and the inter-connectedness of performances from 10km to the marathon, we are a long, long way from going under two hours.

It's not the same as for you or I, who find ourselves a few minutes outside a barrier, and know that six months of hard training and a good day will break it.  This is a world where the margins are tiny - that's why we can look at the pacing strategy and the splits and comment that perhaps it was a little too fast in sections, when in reality, "too fast" means 1 second per kilometer, accumulated over 20 minutes!  The precision of the physiology to run a 2:03 is extra-ordinary.

So consider for instance the progression.  In the modern era, catalyzed by da Costa's breaking of Dinsamo's 1988 record, the improvements in the record are as follows:
23 seconds, 4 seconds, 43 seconds, 29 seconds, 27 seconds, 21 seconds, 15 seconds.

This record is not going to be "smashed" by anyone.  Anything greater than 20 seconds is a big improvement.

The real story is not how often the record is broken, it's how often it isn't

What the sequence above doesn't say, which is more important, is that for every successful attempt, there are probably fifty (a hundred?) unsuccessful ones, where the best runners in the world are on course for the time, for some of the race, then fall away.  Every year, five or six big city marathons start with high hopes - London, Dubai, Chicago, Rotterdam, Frankfurt, Berlin and perhaps two or three others.  Across these races, there are likely twenty "viable candidates", and yet perhaps one in a hundred will come off, despite intent and incentive.

That's why when you look at the record books, you'll see that there are now about 50 performances under 2:06.  Most of those started out as record attempts, and many will have had high hopes up to halfway, or even 30km.  In London earlier this year, about six of the best marathon runners in history went to 25km on course for the world record.  The explosion was huge, and some ended up finishing outside 2:09, or not at all.  I recall Emmanuel Mutai closing at 5:00/km.  The same happens every year in many races.  Even in Berlin yesterday, only one man of a group of three sub-2:06 guys held on to run a 61:51 second half.  Incredible running, but it should highlight just how rare successful attempts are.

The implications - many factors have to align

In the future, that will become more the case.  As this record drops, it will become more difficult to break, and that has some implications.

First, it requires an absolutely perfect day.  London, where the final 8km are run along the embankment, often finds a headwind that could easily cost 2 sec/km and that would be enough to eliminate record possibilities.  Chicago has found itself too hot or too cold.  Berlin was too wet recently.  Dubai hot or windy.  Unless the weather is close to perfect, the record is becoming too strong to break.

Second, the marathon course must be perfect.  I think there are probably only four or five courses in the world that are viable for a world record.  Dubai, Berlin (obviously), London (though the wind, and the number of turns, makes me wonder whether this is still the case, actually), Chicago, and then one or two of the second tier races like Frankfurt where Kipsang ran 2:03:42 a few years ago.

The marathon course is nothing without the best athletes, and so now you also need huge money to attract the best men, in the right numbers, for a record.  London has in the past been so strong that the athletes watch one another rather than risk losing to chase times.  New York gets amazing fields, but the course compromises the final time.  Second-tier marathons with perfect profiles can't get the depth of quality to deliver the record.

The problem then is that there are only a few opportunities a year for the top guys to have a realistic shot.  Now the above three factors need to come together - you need perfect weather on the perfect course, with the best athlete in close to perfect condition, and suddenly you can see why unsuccessful attempts outnumber successful ones so convincingly.

So, what does this mean?  It means that if the record is broken by 15 seconds each time (I think this is a realistic expectation, particularly as it gets stronger), then one can expect it to happen perhaps once every three years.  More likely four or five in the future, but if it were three, then in order to cut another 3:23 off in 15 second intervals, you're looking at around 40 years.

The physiology and performance links behind the 2-hour marathon

So this talk of a sub-2 hour marathon is so premature.  There are a few physiological reasons why it is also not feasible at this stage.  I have written on this extensively before:

• The physiological implications of a sub-2 - economy, max and limits
• The pacing-performance implications of a sub-2.  Why it's not on the horizon

But to sum it up as briefly as possible, the point is this.  If you want a guy to run sub-2 for a marathon, then you're asking for a capability of back-to-back half marathons in under 60 min.  The current WR for the half is 58:23, by Tadese (who hasn't turned that into a decent marathon yet), but for the most part, the top men are running in the low-59s.  The very best break the 59-min barrier.

In other words, the currently best runners on the planet are hovering around 59-minutes for half the distance that people expect them to run in a marathon, at the same pace.  It's a little like expecting Usain Bolt, with his 19.19s 200m best, to go out and run a 400m, slow down just a little, and run a 41s World Record.

Or it's expecting David Rudisha, who can run a 400m in 45s, to hold a pace of 46s for two laps and run 1:32, rather than his 1:41 for 800m.  It just isn't going to happen, and the reason is that the pace we can run for a given distance decreases in a predictable, physiologically 'constrained' manner as the distance increases.

So a man who runs a 59-min half marathon will not be able to sustain two back-to-back 60 min half marathons.  It's just not possible.  And so therefore, before we can even consider the sub-2 hour marathon, we need to look at the ability over the half marathon.  Until humans can run a half-marathon in under 58-minutes (and here, I'm talking low-57), it will not be possible to produce 59:59 twice in a marathon.

And that can be taken one step further, to 10km.  If you are going to see a 57:x half marathon, then you should also be seeing a 10km that is substantially faster than the current 26:x.  The 10km performance required to run a 57 is probably in the high 25s.

It's possible, of course, that the change could come from the ability to sustain high speeds, rather than to nudge the entire system faster.  In other words, the runners of the future could well run at current 21km paces for twice the distance without the paces for shorter distances changing.  That would change the relationship between intensity and duration as we know it, but it is possible if the threshold capacity of runners changes (substantially) in the future.  But that's not going to come instantly - there are physiological barriers that must be inched out of the way, not leapt right over.

Those relate to the physiological implications, which I have written on before, so I won't go into here.

Bottom line is that talking about a sub-2 hour performance after seeing a 2:03:38 improve to a 2:03:23 is just not feasible.  The next barrier is 2:03, and I'm sure will go within five years.  Then we can begin to work towards 2:02, which will take another ten years, perhaps.

It's a great period for marathon running - every season, fall and spring, we get to anticipate a record at least twice.  2013 has delivered a successful attempt, but it shouldn't lull us into expectation that more of the same is just around the corner.

Ross

How to handle a dog attack

For most people, dog attacks are not very common. But they happen occasionally, and the experience can be traumatic. Incidentally, they are also a good reason why I am not a big fan of barefoot walking or running. Broken glass pieces and nails can be a problem if you are barefoot; so can dog attacks.

The photo below, from Dreamstime.com, shows a charging dog. It reminds me of an incident many years ago where a dog attacked my two oldest sons, who were very young at the time. They were unsuspectingly playing at a park in Southern New Jersey, when I saw a dog running in their direction across the park. Part of what I will say in this post is based on experiences like that.

I should also say that I grew up around dogs. My grandfather had a farm that was managed by my uncle, and dogs were critically important in managing the farm. One problem we had was that domesticated pigs would often become feral, or would mate with wild boars, in some cases leading to a particularly vicious breed of large feral pigs. I was once attacked by one of these feral pigs while hunting. One of the farm dogs came to my rescue and probably saved my life.



If you are like most people, when you go walking outdoors, you do not carry a walking stick or a cane. Maybe you should. But if you don’t, thick-soled sneakers can be used in a reasonably effective defense in a dog attack situation.

Dogs attacks’ main targets: The faces of children

Dogs tend to be loyal friends, but they must be monitored for signs of aggression, and can be particularly dangerous to children. A significant proportion of dog attack victims are children 5 years of age or younger, who more often than not sustain injuries to the face, with secondary target areas being the hands and feet ().

At the time of this writing the web sites Documentingreality.com and Arbtalk.co.uk had some grisly photos of dog attack victims (, ). They show evidence that the face is often targeted, and some possible consequences of real dog attacks.

Artificial selection: Dogs and Moby-Dick

Modern dogs are descendants of wolves who came into contact with humans about 12,000 year ago. (This general date is often cited, but is the subject of intense debate, with DNA studies suggesting much earlier contact.) Wolves are apex predators; this was true also for wolves that lived around the time they first came into contact with humans. They hunt and live in packs, and rely on fairly complex body language, a variety of sounds, and a keen sense of smell to communicate.

Even being apex predators, wolves were no match for humans. Therefore, as humans and groups of wolves co-evolved, dogs emerged. Dogs evolved instincts that made them sociable toward and submissive to humans, particularly those humans who fed them and also asserted authority over them – those become their “owners”.

Humans, in turn, came to rely heavily on dogs for protection and hunting, and probably evolved instincts that are still largely unexplored today. For example, there is strong evidence suggesting that having pet animals, many of which are dogs, is generally health-promoting (, ).

The evolution of sociability and submissiveness traits is an example of what is often referred to as “artificial selection”, where animals and plants evolve traits almost exclusively in response to the selection pressure applied by humans. In the case of dogs, this was later taken to new heights through selective breeding; leading to the emergence of a variety of dog breeds, some for utilitarian purposes and others for pure vanity, each with very distinctive characteristics.

Interestingly, artificial selection applied by humans does not always produce more sociable and submissive animals. The opposite happened around the mid 1800s due to excessive hunting of sperm whales. The least aggressive were easier to kill, so they were overhunted. Over generations, this placed selection pressure in favor of the evolution of aggressiveness toward humans. The attack on the Essex by a large bull sperm whale, which served as inspiration for Herman Melville's novel Moby-Dick, was one of the first incidents that resulted from this selection pressure (). Whaling increased, and, predictably, attacks started becoming more and more frequent.

When a dog attacks, stand your ground in a non-threatening way

Dogs, like wolves, are territorial animals. Many dog attacks are likely motivated by humans invading what a dog perceives as its territory at a given point in time. I mentioned earlier in this post that a dog once attacked two of my children. They were playing at a park during the winter. Nobody else was there. I saw this large black dog running from a distance in their direction, and I immediately knew that it was trouble. The dog probably saw us as invading its territory.

Having grown up surrounded by dogs, I pretty much knew what to do. I walked toward my children and placed myself between them and the charging dog. I told the children not to move at all, just freeze. The dog came running until it realized that we were not running. It was a “fake charge”, like most are. It stopped close to me, and barked very aggressively, coming closer. I was wearing boots. I raised one of my boots toward the dog’s snout, and when it bit it, I pushed the boot against its snout.

Here is where I think most people would tend to make a key mistake. They would probably try to hurt the dog to scare it off, by, say, kicking the dog as they would kick a soccer ball. The problem is that, because the dog is a lot faster than they are, if they do that they may end up missing the dog entirely and worse - they may end up losing their balance and falling to the ground. This is when dogs can do the most damage, since they would go for the face of the fallen person.

As a side note, often you hear that dogs attack the throat of their human victims, but that is not what the statistics show. Most victims of dog attacks display injuries on the face and extremities. The "myth" that dogs target the throat is probably based on the notion that dogs attack humans because they see them as prey. However, with exception of feral dogs such as Australian dingos, evidence of dogs preying on humans is very rare. I've reviewed many dog attack photos for this post, and could not find one with evidence that the throat was targeted.

So I pushed my boot against the dog’s snout a few times, firmly but not with the goal of hurting the dog, and did not do anything threatening toward the dog otherwise. This calmed the dog down a bit, but it was still acting aggressively and would not go away. Sometimes firm commands to "seat", "stop", "go away" make the dog react submissively. I tried them but they didn't work; instead they probably made the dog more excited. Then I did what probably is the one thing that most land animals instinctively fear from humans …

Sapiens the thrower

I picked up a few pieces of ice from the ground and threw at the dog. One piece of ice hit the dog on the side of its body; a couple of others were glancing blows. As a result the dog became visibly confused and submissive (telltale sign: tail between the legs), and ran away. Here is where another big mistake may happen. People may try to hurt the dog and become too excited when throwing objects at it. In doing so, they may end up not only missing the dog with the flying objects that they are throwing, but they may also excite the dog, and face another attack.

The best approach here is to focus on having whatever you are throwing at the dog land on top of or as close to the dog as possible; explicitly without trying to hurt it, in part because this improves your aim. Having flying objects coming from you toward the dog is enough to trigger the dog’s instinct to get out of the way of “Sapiens the thrower”. Moreover, if you don’t try to hurt you’ll be relatively calm, displaying the type body language that will trigger submissiveness.

I’ve long suspected that throwing has been a key component of Sapiens’ climb to the top of the food chain, to the point that all land animals have an instinctive fear of humans – even large predators, and much bigger animals such as elephants (as long as they are not “in musth”). One short video has been circulating on YouTube for years; it has various hunting scenes where primitive spears are used (). Many find this video cruel. It clearly shows the enormous evolutionary advantage of humans being able to throw pointy things at other animals. If humans happened to live when Tyrannosaurus rex was around, there is no doubt in my mind that the latter would be the prey.

Keep your face away and your hands closed

Typically you’ll avoid a full-blown dog attack by only standing your ground for a while and not acting aggressively toward the dog. After a short standoff period, you’ll just walk away unharmed. Unfortunately this may not happen if you are facing a dog that has been trained to attack. In this case, having a stick or something like it will help a lot. (In circus acts lions are “pushed around” by trainers holding objects like sticks and wooden chairs; sometimes that doesn't end well - .) If you don’t have one it would be useful to be wearing shoes that can withstand several bites. If not, you can use a piece of clothing, such as a bundled jacket, as a shield.

If you have a stick, or something like a stick, you should not try to hit the dog with it. You should place it near the snout, and push the stick against it each time the dog bites. If you do this calmly and firmly, without trying to hurt the dog (remember, the dog is a lot faster than you are), you will probably discourage biting after a while, turning the attack into a standoff.

What if you don’t have anything with which to defend yourself at first, and a dog attacks you? Keep your hands closed into fists, to avoid having fingers bitten off, and do your best to keep the dog away from your face. As desperate as these situations may be, try to be calm and look for objects that you can use to push the dog away, that you can throw at the dog, or that can be used to wrap around your arms. Frequently there will be objects around that can be of use – e.g., sharp stones, glass bottles, pieces of canvas, loose pieces of a fence, a hose, a tree’s branch. If you fall, try to stand up right away. Very likely you'll sustain injuries to your arms, and possibly legs.

Military and law enforcement personnel are often trained on fighting techniques to handle dog attacks barehanded, such as neck cranks, sharp blows to the throat of the animal, and blinding techniques. I am not sure whether these would be really useful to the average person. In any case, this post is not aimed at military and law enforcement personnel who deal with dog attacks on a regular basis.

Eat beef liver

Beef liver is nature’s super-multivitamin. (Beef heart is just as nutritious.) Dogs, like wolves, have an exquisite sense of smell. If you have seen one of the documentaries about the groundbreaking research by Shaun Ellis (a.k.a., “The Wolfman”), you probably know that wild wolves tend to strongly associate consumption of organ meats with very high status in a pack, to the point that they will instinctively act submissively toward humans that consume organ meats. It is quite possible that dogs do that too. So if you eat beef liver, maybe a dog will “think twice” before attacking you.

Offer the dog a cigarette and a beer

Most dogs can become aggressive from time to time, but not dogs that know how to chill. Therefore, you may consider carrying special dog cigarettes and beer around - only some brands work! Okay, a clarification: the "eat beef liver" advice is not a joke, nor are the others above it.



Notes and acknowledgements

The “charging dog” photo is from Dreamstime.com. The “drunken dog” montage was created with photos from the blog Agrestemundica.

Cesar Millan's site has a number of good suggestions on how to handle dog attacks (). However, I personally think that the way he handles dogs (e.g., often with open hands) is dangerous if copied by an inexperienced person. There is a great deal of "hidden" information that is conveyed to dogs by nuances of Cesar's body language. Those nuances are difficult to copy by an inexperienced person.

An interesting source of information on how to handle dog attacks is the web site Fightingarts.com (, ).

A 2:03:23 marathon world record: Analysis and pacing

Wilson Kipsang's 2:03:23 WR: Thoughts and analysis

Wilson Kipsang yesterday became the 32nd man since WWII to hold the marathon world record.  He broke countryman Patrick Makau's World Record by 15 seconds, setting a new mark of 2:03:23.  A spectacular performance, in which he managed his effort perfectly, showing patience and the right level of aggression at the right time to finish superbly.

Today I share some thoughts, based on the chat on Twitter yesterday, concerning the race, the pacing, and the prospects for that sub-2 hour marathon that people seem very eager to talk about.

I'll tackle the analysis in two parts, one analyzing the race, and later, something on the 2-hour barrier.

The race was managed very well by Kipsang

Below is a graph showing the 5km split times and paces for the race, and includes a projection for 5km based on the final 2.2km, where Kipsang really picked it up.

So, they start fast - the projected time all the way through the first 20km was under the WR.  They reached halfway in 61:32, projecting a 2:03:04, and that was, if anything, perhaps a little too fast.  It set the second half up as a really attritional race - nobody was going to run even or negative splits, and the question was whether any of the big three - Kipchoge, Geoffrey Kipsang or Wilson Kipsang - would hang on well enough to break 62 and the World record.

The pace got slower after halfway.  The section from 20km to 25km was the slowest of the race, which you can see as the peak in the graph above.  Note however that the pace never once dipped below 3:00/km, and that the range was between 2:54 and 2:59.  That's remarkably precision.

That slow 5km interval, and the one immediately after it (25km to 30km) were probably critical to the record because they set the final 10km up.  I have my doubts around how the result would have looked had they continued to push at the 2:03 pace.  It was important to regather, even though it meant slowing down to around 2:06 pace for a short while.

Once regathered, Kipsang was mighty impressive in the final 10km.  He took the initiative, as the "senior" man in the race, and drove the pace even faster.  Only Kipchoge was able to respond and that was fleeting too.  Kipsang ran a few kilometers in 2:49 in that second 30km to 40km, which means there was some in the range of 3:00 too.

So it was a little more varied there, indicating either a change in wind direction (the weather was almost perfect, but not quite), or that Kipsang was digging deep, then finding he needed some active recovery, then digging deep, and recovering, and so on.

Eventually, with 2km to go, he found the big final effort and finished incredibly fast - 2:49/km for the final two, and that was ultimately the difference.  15 seconds, and it came, largely in those final kilometers.  Of course, that's only part of it - the work had been done to get there.

Overall, it was a very well controlled race. Mature, patient, but also aggressive.  His pace-makers did an amazing job up to 30km, and while they may have been just a touch fast from 10km to 20km, it never got out of control.

Taking a broader view, Kipsang paced the marathon almost like a mile race.  If you break the race into quarters, you get the following for his 10km splits:  29:16 - 29:03 - 29:42 - 29:11 (plus that final surge).  The "shape" of that race looks like a typical mile WR - Fast start, slowest in the third quarter, and then the surge.  It was an excellent management of his physiological resources.

In terms of where improvement can come, Kipsang finished very fast, suggesting a reserve, and the ability to go slightly faster.  But it's not huge.  It's not like when you or I finish a 10km and find a surge in the final kilometer that sees us run 20s/km faster than our race average.  In this world, a reserve is being able to go 4-5 seconds per kilometer faster, and so it really is on the limit.

Kipsang is also 31, in his fourth year of marathon running, and set this WR in his 7th race, which is a long time to reach a peak.  Typically, the fastest marathon of an athlete's career happens between 2 and 4, though there are exceptions (Gebrselassie took a while to perfect the race, and then improved steadily quite late).  Kipsang then, may follow a similar approach, and improve again, but the 'safer bet', as it always is, is that he won't.

Behind him, Kipchoge made a big improvement on his debut, which was already impressive at 2:05 from earlier this year.  He's now a 2:04 man, and on the path towards 2:03, so it will be very interesting to follow whether he can continue that, or whether there's a 'glass ceiling'.  The same goes for Geoffrey Kipsang, who "only" ran 2:06:26, but was there for three quarters of the race, and who may yet be able to turn that into an entire race one day.

Then of course there are the Ethiopians, a group of young runners in the 2:04 category, and who may challenge, and there are other Kenyans who've been hovering in the same region.  Marathon running is incredibly deep and strong at the moment, which means we'll get to enjoy similar races and record attempts at least three or four times a year for the foreseeable future.

But for now, it's Wilson Kipsang, with a spectacular performance, who holds the distinction of being the fastest ever.

More later on the 2- hour marathon.

Final thought - the guy who ambushed the breaking of the tape to promote prostitution has been charged with trespassing.  What should happen to him is that he should be sent to Kenya, preferably Eldoret or Iten where all the elite runners train, for three months of community service work.  Let him serve in any was possible (he can carry water and drive behind the runners on long training runs), and learn some respect for the runners of Kenya in the process.  Idiot.

Ross

Berlin Marathon 2013: Live splits and analysis

World Record! 2:03:23 Wilson Kipsang
Live Splits and Analysis

Wilson Kipsang has broken the Marathon World Record!  2:03:23 in Berlin.

Here is how he did it, splits and analysis from the race!  I'll post more later!

Overall splits Men

5km:  14:34.  2:55 per km, projecting 2:02:56
10km:  29:16.  14:42 for the last 5km, pace of 2:56/km. Projected time now 2:03:29
15km:  43:45.  14:29 for the last 5km, pace of 2:54/km, the fastest so far. Projecting 2:03:04.
20km:  58:19.  14:34 for the last 5km, pace of 2:55/km.  Projecting 2:03:02
Halfway:  61:32. Easy calculation, it projects 2:03:04, a WR by 34 seconds
25km:  1:13:13. 14:54 for last 5km, pace of 2:59/km, so slowest segment. Projecting 2:03:35
30km:  1:28:01.  14:48 for the last 5km, pace of 2:58/km.  Projection of 2:03:48
35km:  1:42:36.  14:35 for the last 5km, pace of 2:55/km. Projecting 2:03:41
40km:  1:57:12.  14:36 last 5km, projecting 2:03:38. Epic finish coming up!
Finish: 2:03:21.  The World Record is gone!

40km

It's on. Final 2.195km at 2:54/km will get the WR.  By 1 second!  As you can see above, that's what they've done since 30km, and so the record is a real possibility.  Kipsang leads Kipchoge by about 10 seconds, so it is a one-man race for the WR.  Silence now until the end, I'll fill in the blanks later.  This will be a "sprint" through the Brandenburg Gates for the World Record.

Kipsang has slowed slightly in the last 2km, so he needs a pick up.  But it's so close now, if he can just dig in and find 5 minutes of effort, he'll get this.

35km

The pace has now picked up, with the pacemaker having dropped off.  Wilson Kipsang has led the upturn in pace, which has seen the last 5km covered in 14:35 .  That included a 2:52 34th kilometer, very fast.

Wilson Kipsang is the aggressor, leading the race, but with company from Geoffrey Kipsang and Eliud Kipchoge.  Kipsang, as the senior, pedigreed man, obviously has the pressure and obligation to keep the record viable.

With 10km to go, the TV graphic suggests that a 29:30 10km will be needed.  That is definitely feasible.

The pacmaker fought to about 31 km then dropped off, leaving the big three.  It's the Kipsangs, Wilson and Geoffrey, along with Kipchoge.  So as expected, those three fight for the win.  Whether their fight produces a record, that's the intrigue.

30km

They've remained slightly slower than WR pace.  2:58/km gives 14:48 for the last 5km, and a projection of 2:03:48.

So, having been well under WR pace at halfway, it's now going to take a real aggressive final 10km to get the WR.  Whether anyone will take the 'risk' in the company of other men is going to determine how close they get.  That will depend on how they each feel, of course.

At this stage, it's a good time to consider who the viable candidates are.  Wilson Kipsang, Geoffrey Kipsang and Eliud Kipchoge are all there, as is one pacemaker, and Kirwa and Kipchirchir.  An all Kenyan front five, plus the pacemaker Rono.  Five men is good in the sense that 'company' helps in the latter part of the race, but it will be interesting to see how the racing affects the pacing, as it were.

It was this segment where Patrick Makau made the surge that would drop Gebrselassie on route to the current WR in Berlin.  He ran a 5:30 2km segment then, which certainly helped his race, but probably cost him some time.  So the comparison with Makau, which up to now has seen 2013 ahead, will probably look different at 30km, but that's still OK - there are 12km to go from that point, much can happen.

25km

The last 5km were run in 14:54, which is 2:59/km, the slowest segment of the race.  You can tell the pace had slowed because the front group at halfway was thinning out, and it has now expanded again, as runners who had dropped off have come back on.  That's always a sign.  The projection now is 2:03:35, and so it has suddenly come back from being a big WR projection, to a touch and go race.

There is some talk that the runners were benefiting from a tailwind between 10 and 20km, which is now gone.  These are the subtleties that affect WR potential...

At this stage of the race, patience really counts for a lot, so the slowing is not necessarily a bad thing.  The temptation, as the field thins out, is to get aggressive, because you're on the way "home", as it were.  We've seen in London and other big city races how aggression at 25km often blows the race open, but it comes at the cost of the fast time.  So it's important here to be patient, and avoid a 5:35 surge for 2km that can easily derail the WR.  Kipsang of course did that in the Olympics, not off a WR pace, but may have learned from that.  They do have a buffer of around 30 seconds for this second half - a 62:00 still gives a WR.

Halfway

61:32, so a WR projection by 34 seconds.  It promises to be an intriguing second half.  For one thing, the pacemakers will drop at around 30km, and then it will be up to the big three, assuming they're all there, to decide how best to push the pace to keep the WR in view, while still racing and not pulling a colleague to the WR.  That will be perhaps the race's decisive moment.

20km

58:19 at 20km, the projection is for a 2:03:02.  The last 5km was 14:34, so 2:55/km, but there were reports that the 18th kilometer was 2:52, which is very fast and suggests a little bit of oscillation.  Again, the athletes can see their pace and the projected time continuously in Berlin, so when the pace is faster, it's not an accident caused by lack of information, it's a conscious decision to ramp the pace.  They are being incredibly aggressive, and that makes for an interesting second half.  They should hit halfway in about 61:30, and so the second half is guaranteed to be attritional.  The question now is whether it is attritional enough to cost them the WR, or whether they hang on?

15km

The pace has actually increased - 14:29 for the last 5km, and the projected time is now down again, to 2:03:04.  This is quick, and maybe cause for concern.  If you're 15 to 20 seconds up on WR pace through halfway, then that's bordering on reckless.  So it will be interesting to see how the section 25 to 35 km goes.  That's often where the "interest" payments are made.

A TV graphic is showing that they're currently 36 seconds faster than Makau was at the same stage - the coverage is good so far.  Remember that Makau had a race with Gebrselassie that really jacked the pace up after halfway, so that gap may come down later.  The optimal way to run is even pace, so the Makau comparison is less informative, but interesting.  Also, in Berlin, runners have access to the car in front of them, which gives all the information required to manage the pace.  It even gives a projected time, so if they're running under 2:03-pace, then it's because they have chosen to, not because they're making a mistake in the absence of information, which is important to consider.

Florence Kiplagat has gone through 15km in 49:27, which projects a 2:19:06, so she has slowed very slightly, but still on course for a big PB and significant performance under 2:20.

10km

The pace has been maintained, 14:42 for the last 5km.  That's very steady.  The biggest challenge is consistency, so it would be good to see splits by kilometer, rather than 5km, because that would tell you exactly how the pace is fluctuating.  Physiologically, there's a big difference between going 2:52-3:00-2:52-3:00, and running 2:56 every kilometer, even though overall it's the same pace.

So far, that seems to not be the case.  A TV graphic showed a sequence of kilometer splits and the range seems to be narrow - 2:54 to 2:58, so it's a good pacing job so far.  If that continues, then the record is on, and the only determinant is the condition of the atheltes.

No splits from the leading woman, who is Florence Kiplagat.  They're saying her timing chip is not working, so the only splits coming through are for the women in the group behind her.  Will get a split as soon as possible.  She's just gone through 12km in around 39:30, which is 2:18:50 pace, so Kiplagat is going fast too.

5km

14:34, which projects 2:02:56.  The target was apparently 14:40, so they're inside it.  For now, not too damaging (though of course there may have been a 2:40 km in there, I'm not sure), but that is quick.  There's more risk of losing the record by going too fast at this stage.  Not surprisingly, the big three are in the group, along with perhaps 7 or 8 others.  That should thin out at this pace.

Start

As we wait for the first split. a prediction.  I don't think the WR will fall.  Too many things have to be absolutely perfect.  Weather, conditioning of the athlete, the pacing, the intent, and the presence and support of other runners when it counts.  If any of those factors are even 5% below optimal, the price is stiff and the record is gone.

I don't think that the three big names in this race have the necessary ability, so my call is a time just outside 2:04.  Let's call it 2:04:15.  5km split next.

Waist-to-weight ratios in pictures: The John Stone transformation

John Stone is a bodybuilder and founder of a bodybuilding and fitness web site (). There he has provided pictures and stats of his remarkable transformation, which were used to prepare the montage below.



John’s height is reported as 5' 11.5". Below the photos are the months in which they were taken, the waist circumferences in inches, the weights in lbs, and the waist-to-weight ratios (WWRs). Abhi was kind enough to provide a more detailed plot of John Stone’s WWRs ().

Assuming that minimizing one’s WWR is healthy, an idea whose rationale was explained here before (), we could say that John was at his most unhealthy in the photo on the left.

The second photo from the left shows a slightly more healthy state, at a reported 8 percent body fat (his lowest). The two photos on the right represent states in which John’s WWR is at its lowest, namely 0.1544. That is, in these two photos John minimized his WWR; at a reported 14 and 13.8 percent body fat, respectively.

When we look at the WWRs in these photos, it seems that he is only marginally healthier in the second photo from the left than in the leftmost photo. In the two photos on the right, the WWRs are much lower (they are the same), suggesting that he was significantly healthier in those photos.

Interestingly, in both photos on the right John reported to have been at the end of bulking periods. Whenever he entered a cutting period his WWR started going up. This suggests that his ratio of lean body mass to total mass started decreasing just as soon as he started cutting. I suspect the same would happen if he continued gaining weight.

Which of the two photos on the right represents the best state? Assuming that both states are sustainable, over the long run I would argue that the best state is the one where the WWR was minimized with the lowest weight. There whole-day joint stress is lower. This corresponds to the photo at the far right.

By sustainable states I mean states that are not reached through approaches that are unhealthy in the long term; e.g., approaches that place organs under such an abnormal stress that they are damaged over time. This kind of damage is essentially what happens when we become obese – i.e., too fat. One can also become too muscular for his or her own good.

Could we have evolved traits that are detrimental to our survival?

Let us assume that we collected data on the presence or absence of a trait (e.g., propensity toward risky behavior) in a population of individuals, as well as on intermediate effects of the trait, downstream effects on mating and survival success, and ultimately on reproductive success (a.k.a. “fitness”, in evolutionary biology).

The data would have been collected over several generations. Let us also assume that we conducted a multivariate analysis on this data, of the same type as the analyses employing WarpPLS that were discussed here in previous posts (). The results are summarized through the graph below.



Each of the numbers next to the arrows in the graph below represents the strength of a cause-effect relationship. The number .244 linking “a” and “y” means that a one standard deviation variation in “a” causes a .244 standard deviation increase in “y”. It also means that a one standard deviation variation in “a” causes a 24.4 percent increase in “y” considering the average “y” as the baseline.

This type of mathematical view of evolution may look simplistic. This is an illusion. It is very general, and encompasses evolution in all living organisms, including humans. It also applies to theoretical organisms where multiple (e.g., 5, 6 etc.) sexes could exist. It even applies to non-biological organisms, as long as these organisms replicate - e.g., replicating robots.

So the trait measured by “a” has a positive effect on the intermediate effect “y”. This variable, “y” in turn has a negative effect on survival success (“s”), and a strong one at that: -.518. Examples: “a” = propensity toward risky behavior, measured as 0 (low) and 1 (high); and “y” = hunting success, measured in the same way. (That is, “a” and “y” are correlated, but “a”=1 does not always mean “y”=1.) Here the trait “a” has a negative effect on survival via its intermediate effect on “y”. If I calculate the total effect of “a” on “w” via the 9 paths that connect these two variables, I will find that it is .161.

The total effect on reproductive success is positive, which means that the trait will tend to spread in the population. In other words, the trait will evolve in the population, even though it has a negative effect on survival. This type of trait is what has been referred to as a “costly” trait ().

Say what? Do you mean to say that we have evolved traits that are unhealthy for us? Yes, I mean exactly that. Is this a “death to paleo” post? No, it is not. I discussed this topic here before, several years ago (). But the existence of costly traits is one of the main reasons why I don’t think that mimicking our evolutionary past is necessarily healthy. For example, many of our male ancestors were warriors, and they died early because of that.

What type of trait will present this evolutionary pattern – i.e., be a costly trait? One answer is: a trait that is found to be attractive by members of the other sex, and that is not very healthy. For example, a behavior that is perceived as “sexy”, but that is also associated with increased mortality. This would likely be a behavior prominently displayed by males, since in most species, including humans, sexual selection pressure is much more strongly applied by females than by males.

Examples would be aggressiveness and propensity toward risky behavior, especially in high-stress situations such as hunting and intergroup conflict (e.g., a war between two tribes) where being aggressive is likely to benefit an individual’s group. In warrior societies, both aggressiveness and propensity toward risky behavior are associated with higher social status and a greater ability to procure mates. These traits are usually seen as male traits in these societies.

Here is something interesting. Judging from our knowledge of various warrior societies, including American plains Indians societies, the main currency of warrior societies were counts of risky acts, not battle effectiveness. Slapping a fierce enemy warrior on the face and living to tell the story would be more valuable, in terms of “counting coup”, than killing a few inexperienced enemy warriors in an ambush.

Greater propensity toward risky behavior among men is widespread and well documented, and is very likely the result of evolutionary forces, operating on costly traits. Genetic traits evolved primarily by pressure on one sex are often present in the other (e.g., men have nipples). There are different grades of risky behavior today. At the high end of the scale would be things that can kill suddenly like race car driving and free solo climbing (, ). (If you'd like to know the source of the awesome background song of the second video linked, here it is: Radical Face's "Welcome Home".)

One interesting link between risky behavior and diet refers to the consumption of omega-6 and omega-3 fats. Risky behavior may be connected with aggressive behavior, which may in turn be encouraged by greater consumption of foods rich in omega-6 fats and avoidance of foods rich in omega-3 fats (, ). This may be behind our apparent preference for foods rich in omega-6 fats, even though tipping the balance toward more foods rich in omega-3 fats would be beneficial for survival. We would be "calmer" though - not a high priority among most men, particularly young men.

This evolved preference may also be behind the appeal of industrial foods that are very rich in omega-6 fats. These foods seem to be particularly bad for us in the long term. But when the sources of omega-6 fats are unprocessed foods, the negative effects seem to become "invisible" to statistical tests.

We share an ancestor who probably lived no more than 640 years ago

This post is a revised version of a previous post. The original post has been or will be deleted, with the comments preserved. Typically this is done with posts that attract many visits at the time they are published, and whose topics become particularly relevant or need to be re-addressed at a later date.

***

We all evolved from one single-celled organism that lived billions of years ago. I don’t see why this is so hard for some people to believe, given that all of us also developed from a single fertilized cell in just 9 months.

However, our most recent common ancestor is not that first single-celled organism, nor is it the first Homo sapiens, or even the first Cro-Magnon.

The majority of the people who read this blog probably share a common ancestor who lived no more than 640 years ago. Genealogical records often reveal interesting connections - the figure below has been cropped from a larger one from Pinterest.

You and I, whoever you are, have each two parents. Each of our parents have (or had) two parents, who themselves had two parents. And so on.

If we keep going back in time, and assume that you and I do not share a common ancestor, there will be a point where the theoretical world population would have to be impossibly large.

Assuming a new generation coming up every 20 years, and going backwards in time, we get a theoretical population chart like the one below. The theoretical population grows in an exponential, or geometric, fashion.

As we move back in time the bars go up in size. Beyond a certain point their sizes go up so fast that you have to segment the chart. Otherwise the bars on the left side of the chart disappear in comparison to the ones on the right side (as several did on the chart above). Below is the section of the chart going back to the year 1371.

The year 1371 is a mere 640 years ago. And what is the theoretical population in that year if we assume that you and I have no common ancestors? The answer is: more than 8.5 billion people. We know that is not true.

Admittedly this is a somewhat simplistic view of this phenomenon, used here primarily to make a point. For example, it is possible that a population of humans became isolated 15 thousand years ago, remained isolated to the present day, and that one of their descendants just happened to be around reading this blog today.

Perhaps the most widely cited article discussing this idea is this one by Joseph T. Chang, published in the journal Advances in Applied Probability. For a more accessible introduction to the idea, see this article by Joe Kissell.

Estimates vary based on the portion of the population considered. There are also assumptions that have to be made based on migration and mating patterns, as well as the time for each generation to emerge and the stability of that number over time.

Still, most people alive today share a common ancestor who lived a lot more recently than they think. In most cases that common ancestor probably lived less than 640 years ago.

And who was that common ancestor? That person was probably a man who, due to a high perceived social status, had many consorts, who gave birth to many children. Someone like Genghis Khan.

Bolt vs Farah at 600m. The extremes meet, who wins?

Bolt vs Farah over 600m: The extremes meet in the middle (kind of, physiologically...)

For athletics fans, the prospect of Usain Bolt vs Mo Farah over 600m offers an enthralling spectacle where the most dominant athletes at the extremes of track running test themselves with one foot in the other’s domain.  I suspect it is highly unlikely to happen, but it's a great platform for some debate around performance physiology.

Predicting the winner is a fun exercise in stats, performance analysis and physiology (performance analysis - it's not an exact science, remember!).  

The fascinating question for this one is where do the physiologies of these two “extreme” athletes cross?  Of course, bear in mind that there are athletes in the middle who would arguably beat both Farah and Bolt over 600m, and by a long way.  When David Rudisha broke the 800m WR in London last year, his 600m split time was 1:14.3, and that's about as fast as I suspect Farah or Bolt could run in a straight 600m.  

Rudisha's 1:40.91 predicts something under 1:12 for 600m (the world record is 1:12.81, and that's from Johnny Gray, who was 1.6 seconds slower than Rudisha at his best), so he would certainly win a 600m were he in it.  In fact, so would just about the entire men's 800m Olympic final field, and a good few 400m, 400m hurdlers and 1500m runners (the 800m/1500m combo guys) too - this 600m is not about finding the best athlete, but about some fun and publicity!

Physiology at the 'extremes'

Physiologically, making the prediction invites some discussion over the origin and capacity of the energy pathways used by each, and what it means for fatigue. 

It boils down to different questions for each man.  For Bolt, it’s whether he can withstand the fatigue of going three times further than his normal race distance, and how much he would need to slow down to avoid complete failure to even finish the distance?

For Farah, it’s whether his top speed is high enough to pressurize Bolt into that premature fatigue? 

A quick physiological lesson will explain:  When you see athletes tying up and slowing down dramatically at the end of a sprint race, what you are witnessing is the combination of a "failure" of energy production (the supply can't meet the demand), a build up of metabolic by-products in the muscle and the central and peripheral responses to these changes.  Nobody knows the full explanation for this, and it’s likely more complex than any current theory can explain, but the result is a reduction in muscle contractility with sub-maximal muscle recruitment.  

Studies have shown, for instance, that at the end of a 400m race, drop-jump performance declines by 39% and that muscle activation increases, which shows the cumulative effects of fatigue on muscle function - more recruitment needed for less force/power.  Other studies show that this happens despite pacing, and the presence of some muscle unit reserve, which implies that fatigue occurs partly in the brain, partly in the muscle.

The source of energy is crucial to both fatigue processes, because it affects the biochemical changes occurring in the muscle.  Bolt and Farah rely on different pathways for their energy.  Bolt has a highly developed pathway that produces the energy needed for muscle contraction very rapidly, but not for very long.  His energy comes primarily from what are known as oxygen independent (or anaerobic, though this word is avoided by many) pathways.  They are all about the speed of energy supply, and the consequence – a build up of metabolites, is an accepted downside because he doesn’t need more than 20 seconds of explosive power. 

Farah, on the other hand, can produce energy for hours, but more slowly, using primarily oxygen dependent, or aerobic pathways.  The upside is less peripheral accumulation (though glycogen depletion is, eventually, a theoretical 'limit'), the downside is the rate of supply.  This difference accounts for the clear differences in the optimal pacing strategy between short duration and long-duration events, something I summarized in this review article for BJSM.

There is always an overlap, with some contribution from both pathways, no matter the distance, but for shorter, high intensity exercise like sprinting, the oxygen-independent pathways are more heavily relied upon (in the 200m event, for instance, the split is around 70%-30% in favor of energy production without oxygen.  By 1500m, it is reversed to 30%-70%). 

So, as much as Bolt and Farah lie at the opposite ends of the performance spectrum, they are also extremes of biochemistry.  Muscle histology and function also differ – Bolt’s are more contractile, able to contract rapidly and forcefully, but they also fatigue more rapidly.  

The prediction

Over the nominated distance of 600m, Farah would be forced to find a force and speed of muscle contraction and energy production that he is unfamiliar with, while Bolt will be asking his biochemistry to withstand an accumulation of metabolites and resultant fatigue that he is also unaccustomed to.

As for a prediction, the biochemical odds are slightly tilted in Farah’s favor at 600m.  A number of people have attempted to model where the perfect distance is, and using the above-mentioned energy pathway models, have estimated that the perfect distance, with equal performances, lies somewhere between 500m and 550m.   

Those additional 50m, seemingly trivial, probably just give Farah the edge and represent 50m too far for Bolt’s physiology.  Farah’s famous finishing kick, as well as his recent 1500m performance, a European record of 3:28, have shown that he has extra-ordinary sustained speed for a distance runner, so the biochemical “jump” to a 600m may not be as large as the step up from 200m to 600m for Bolt. 

On that performance note, Farah's 600m performance is easier to predict and is more familiar to him - it's something he'd do regularly in training, whereas Bolt would very rarely approach even sub-maximal efforts for this duration.  

Performance-wise, Farah's 3:28 suggests that his 800m performance would be in the range of 1:45 to 1:46.  That would optimally be achieved with a 51-52s first lap, and a 53-54s second lap.  That in turn suggests that a very fast 400m of 49s would be possible.  Then it becomes a question of limiting the slow down, and finishing with a time around 1:14-1:15.  It's about starting fast enough to take advantage of sustainable speed and attenuated slowing down at the end.

Bolt, on the other hand, has to worry about the opposite problem - not starting too fast.  He has run 400m in under 46s almost every year since 2007, including a PB of 45.28s six years ago, and a 45.35s at the age of only 17.  So he may have the natural ability, if he judges the pace well, to edge Farah.  However, six years is a long time, and those low 45s are probably less relevant now, particularly since he has probably gained mass since 2007.  Mass hurts over longer distances, so Bolt has this to deal with as well.  If Bolt does go out in 48s, gaining an advantage of around a second over Farah, he'd need to hold on to around 27s for the final 200m, and I suspect that would be a little too much to ask.

With a month of dedicated training for the 600m distance, my money would be split.  In my opinion, it would be a coin toss - Bolt would be able to change the training enough to adapt just enough to make it incredibly close.  But, if the race were to happen straight after their specialized seasons, Farah has the edge.  I'd pick Farah by about half a second to a second.  Over 550m, maybe it comes down to the lean.  It would be a fascinating meeting of two extremes.  It would sure be fun to watch, and discuss - that happens over on Twitter and Facebook!

Ross

Could grain-fed beef liver be particularly nutritious?

There is a pervasive belief today that grain-fed beef is unhealthy, a belief that I addressed before in this blog () and that I think is exaggerated. This general belief seems to also apply to a related meat, one that is widely acknowledged as a major micronutrient “powerhouse”, namely grain-fed beef liver.

Regarding grain-fed beef liver, the idea is that cattle that are grain-fed tend to develop a mild form of fatty liver disease. This I am inclined to agree with.

However, I am not convinced that this is such a bad thing for those who eat grain-fed beef liver.

In most animals, including Homo sapiens, fatty liver disease seems to be associated with extra load being put on the liver. Possible reasons for this are accelerated growth, abnormally high levels of body fat, and ingestion of toxins beyond a certain hormetic threshold (e.g., alcohol).

In these cases, what would one expect to see as a body response? The extra load is associated with high oxidative stress and rate of metabolic work. In response, the body should shuttle more antioxidants and metabolism catalysts to the organ being overloaded. Fat-soluble vitamins can act as antioxidants and catalysts in various metabolic processes, among other important functions. They require fat to be stored, and can then be released over time, which is a major advantage over water-soluble vitamins; fat-soluble vitamins are longer-acting.

So you would expect an overloaded liver to have more fat in it, and also a greater concentration of fat-soluble vitamins. This would include vitamin A, which would give the liver an unnatural color, toward the orange-yellow range of the spectrum.

Grain-fed beef liver, like the muscle meat of grain-fed cattle, tends to have more fat than that of grass-fed animals. One function of this extra fat could be to store fat-soluble vitamins. This extra fat appears to have a higher omega-6 fat content as well. Still, beef liver is a fairly lean meat; with about 5 g of fat per 100 g of weight, and only 20 mg or so of omega-6 fat. Clearly consumption of beef liver in moderation is unlikely to lead to a significant increase in omega-6 fat content in one’s diet (). By consumption in moderation I mean approximately once a week.

The photo below, from Wikipedia, is of a dish prepared with foie gras. That is essentially the liver of a duck or goose that has been fattened through force-feeding, until the animal develops fatty liver disease. This “diseased” liver is particularly rich in fat-soluble vitamins; e.g., it is the best known source of the all-important vitamin K2.



Could the same happen, although to a lesser extent, with grain-fed beef liver? I don’t think it is unreasonable to speculate that it could.

Alan Oliveira runs 10.57s. Leg length or something else? Over to the IPC and IAAF

Alan Oliveira runs 10.57s: Is it leg length, or something else? Over to the IPC/IAAF

Hot on the heels of a 20.66s World Record for double-amputees in Lyon a week ago, Alan Oliveira of Brazil, the fastest double amputee in the world, today destroyed his own 100m World Record with a performance of 10.57s in the London Olympic stadium.

I wrote about his emergence as the heir to Oscar Pistorius last week, describing the implications of his incredible improvements in 2013.  He last week won the 100m, 200m and 400m titles in the IPC World Championships, and is now a staggering 0.44s faster than the next fastest in history at 100m (Pistorius).  The improvement has come within the last two months, because prior to that, Oliveira's best 100m time was 11.33s.

The leg length - in play, but a red herring

Of course, the current debate is all about his legs, and more specifically, their length.  That is a red herring.  While partly true, there are many reasons to suggest that what Oliveira has achieved in 2013 is not the result of excessively long legs, but some other factor, which has already been proven to exist by scientific research.  Unfortunately, the IPC seem intent on pursuing length as the critical one, with new rules controlling length to be announced soon.

It's unclear what this will mean for Oliveira in the short term, but the problem is that they won't solve the larger problem, and the next athlete to come along with once again push the sport into the same dilemma.

Let's look at the leg length issue in a bit more detail.

London 2012 flashback 

When he defeated Pistorius in the London 2012 200m final last year, the accusation made by Pistorius was that he "couldn't compete with Alan's (long) stride length".  An easy explanation to test, because all it took was counting the strides, and it turned out that Oliveira's stride was not all that long.  In fact, Pistorius took fewer strides than Oliveira, and thus had the longer stride - 92 steps vs 98 steps, for a step length of 2.2 m vs 2.0 m for Pistorius and Oliveira, respectively (remember that a stride is two steps - I counted steps, but report strides later in the discussion).  And the final 100m showed the same pattern - Pistorius' average step length was 2.3 m, compared to 2.2 m for Oliveira.

So, stride length, at least at a superficial level, is not where the advantage came from back then, and it's not the sole explanation now either.

That said, it would be incomplete and false to suggest that Oliveira's leg length should not be the subject of some scrutiny.  In the week leading up to that 200m final, Oliveira revealed in an interview that he had recently increased his blade length by 4cm, taking him from a racing height of 1.77m to 1.81m, and he was clearly relatively taller than his rivals.

To understand what all that means, let's consider how the IPC set the maximum allowable leg length for double amputees.  First of all, it's not an easy task to do - there is no such thing as a "normal height", and when someone does not have legs, then trying to be specific about how tall they would have been is a complex exercise in dealing with ranges.  That's because we don't all share the same limb proportions.

There is an average ratio of say, arms to height, and a similarly average ratio of femur length to total leg length, but these averages don't often apply to elite athletes.  One example is Michael Phelps, the world's greatest swimmer, who stands 1.93m tall and remarkably, wears the same length pants as Hicham el Guerrouj, the world record holder in the mile, who stands only 1.75m tall!

That is, a difference of 18cm in height, with the same leg length.  Such are the variations between people.  One is a swimmer, one is a runner, and they are arguably born to excel in their specific events by virtue of completely different leg to total height ratios.  For pages and pages of similarly mind-blowing stats, I would highly recommended David Epstein's book, "The Sports Gene", which is due out this week.

But for now, let's leave it at the fact that the IPC cannot simply say "You should be X cm tall based on your arm length".

Instead, what they have done is establish a maximum allowable height for each double amputee.  The image below, which was released in the aftermath of the London 2012 controversy, shows the height limits for the key players in this debate.  It invites four thoughts:

Thought # 1 - taller is not necessarily better, and that has important implications

First, notice that Oliveira is allowed race at 185.4 cm, whereas Pistorius was able to go to 193.5 cm.  Presumably, that's a limit based on arm length, modified and improved by femur length to give a total height, which is the absolute maximum for someone who has exceptionally long legs relative to their body (like el Guerrouj).  We know that in London, Oliveira was 181cm, so he was 4cm short of the limit.  He was thus perfectly legal, as I'm sure he is now.  The issue is thus not cheating, but perhaps whether the limits are 'fair'.  

To address that, it's interesting to wonder about why he would stop at 181 cm?  If you're going up from 177 cm as he did, and if longer legs mean better performances (as people somewhat simply suggest), then go to the limit of 185.4 cm. More length, more speed?

The answer to that question is that at some point, going longer becomes counter-productive.  That's because the start becomes so severely compromised (as we saw with Oliveira in London), as well as balance around the bend, that the overall performance gets slower.  Top end speed may be greater, but the net result of longer limbs is less balance and therefore slower times.  Thus, there exists a "sweet spot", an optimal length for each athlete, and that's why none of the top double amputees are competing at their maximum allowable height.  Pistorius, for instance, races at 186 cm.

Thought # 2 - athletes discover the sweet spot by testing, so everyone is "optimized"

The implication of Thought # 1 is that the elite athlete have discovered their optimal sweet spot, because if they didn't, they go maximum length to find more top end speed.  We know from the PR around Pistorius that testing on blades is extensive - he traveled to Iceland often, and representatives of these carbon fiber manufacturers visit athletes for field testing regularly.

Part of the process is discovering how far below the limit the athlete should stop.  So for instance, we should be asking how Oliveira knew to stop at 181 cm prior to London, and why Pistorius was at 186 cm in the first place when he could have gone to 193 cm?  Why not 189 cm?  They had room to play with, but decided not to use it.  The answer is that they're optimized at those 'sub-max' heights.

For Oliveira, however, that may have changed since 2012.  It's conceivable that since his breakthrough (remember that he was just 19 in London last year) he has had more time and more technological support, and thus more opportunity to work out his ideal racing height.  

One source at the IPC reported to me earlier this year that Oliveira had in fact gone shorter, and thus discovered a much faster start and bend performance, driving his times down.  Others are saying he is now even longer - perhaps right up to his 185.4 cm limit.  A curve ball in this debate is that between 19 and 20, he may have grown, and so his upper limit of 184.5 cm from London may have increased, allow him more to play with.  

His 100m performance improvements suggest shorter, because his start is so much better, unless he has improved his balance and co-ordination spectacularly in the last 12 months.  However, we don't know what height he has raced at.  The IPC will, unless they have been grossly negligent in getting the blades measured, and that is surely inconceivable given the obvious focus on them.  They'll have to consider this information as they decide what to do next.  Which leads me on to point 3...

Thought # 3 - the IPC have to change the rule, but how effective will it be, and what do they base the change on?

It's clear that if the current progression continues, the IPC and the IAAF will have to reassess the situation of double-amputees racing in the able-bodied events.  Oliveira won the 400m title at the World Champs this weekend, but with a less than stellar time.  He said after that he doesn't train for the longer distance.  With an Olympic Games coming up in his own country, and with 3 years of preparation, maturity and strength to gain, it's almost inconceivable that he won't at least attempt to run in both Olympic and Paralympic competitions, emulating Pistorius.  Perhaps he will focus on the 200m - another half a second improvement on his 20.66s WR puts him into a final there, with possibilities of a medal should three years produce similar improvements to 2013.  Given that he is only 20, and clearly still in a period of rapid improvement, such an improvement is well within the realms of possibility. 

If he does jump up to the 400m, his chances are even better - the time lost at the start can be recovered over the final 350m, and his top-end speed, which must surely be comparable to Usain Bolt's, as well as remarkable sustained speed in the second half, should see him go considerably faster still.

So, what are the IPC and IAAF to do?  Refer again to the table above, and remember that those maximum height allowances are based on data collected from hundreds if not thousands of people to establish a range of human "norms".  If the IAAF and IPC decide to change them to make Oliveira race at a shorter height, they would have to justify it by saying something along the lines of "We are now adopting mean or average height rather than allowing for extreme individuals within the normal population".  That is, they would have to pretend that extremes like Phelps or el Guerrouj don't exist, and I can't see how that is legally or scientifically defendable.  You have to allow for cases at the extreme end of "normal", which is why the answer to that apparently simple question "What is a normal height?" is so very complex.

Alternatively, they could modify the guidelines slightly, perhaps to 1SD above means, and reduce Alan Oliveira's maximum allowable height subtly.  If it meant he was forced to drop to say, 181cm, he'd be at the same height he was at in London, and that means more of the same debate and performances. 

The point is this:  Because none of the athletes are at the maximum allowable height (see Thought #2), any change in the policy will have to be drastic, or it won't affect them anyway.  And drastic changes mean re-writing the understanding of human anthropometry, possibly discriminating against individuals who are normal but 'extreme', and may thus be impossible to implement.  All in all, very sticky for the IPC.

Thought 4: Leg length possibilities for Oliveira

And then finally, as I return to where I began, this discussion of length may be something of a red herring.  Again, there is no doubt that as the legs get longer relative to total height, the person is more likely to be a successful runner.

However, Oliveira has achieved almost a second of improvement in the 100m within one year.  His 200m performance trajectory is similar.  That invites three possibilities:

1. He is still racing on the same length blades as London (height 181cm).  In this case, his improvement is solely due to training, co-ordination and normal development.  One can still say he has an advantage, but his improvement is distinct from it.
   
   
2. He has changed up, and gone to longer legs, then I find it hard to believe that 3 to 4cm (he only has this to play with, it's not as though he can race at 195cm - see table above) can contribute to that kind of performance.  This is particularly true given that any increased length must surely compromise the start and bend, and so the effect is even larger.  Simply put, it cannot be solely due to running "taller" in 2013
   
   
3. He has changed down, and found a better "sweetspot" that gives him a better start and bend performance, faster overall, with some accepted reduction in top speed.  If this is the case, and he's running at say 179cm, then it's even more of a problem for the IPC and IAAF because whatever they plan to change in their guidelines would need to be even more drastic.

What if stride length is not the factor at all?

But what if it is not in the length at all?  What if that simple exercise of counting his strides, and comparing them to Oscar Pistorius' in London 2012 actually hints at the solution?

Remember, that night, Pistorius took 49 steps on the bend and 43 steps in the home straight.  That is a step length of 2.0 and 2.3 m respectively.  Oliveira, on the other hand, had average step lengths of 1.92 m on the bend and 2.2 m on the straight.  In a race of absolute stride lengths, Oliveira is second-best.

The key, however, is the stride length relative to body height - someone who has excessively and disproportionately long legs will have a longer stride relative to their height, so you can partially test this 'accusation' by comparing stride length to total length.

So, running that logic for 2012, if Pistorius, at 186 cm, takes 230 cm steps, his step length to height ratio is 1.24.  Oliveira, at 181 cm with 220 cm steps, is at 1.22, and so in fact, Pistorius' steps are actually longer, not only in absolute terms, but also relative to his height.  This is the primary reason that I wasn't convinced that Oliveira's advantage was stride length back in 2012, and I'm not convinced now (though I will allow for the possibility that he has since increased his length - see Thought # 4).

The answer is more likely stride speed, not length. And that closes the loop

The ratio is however significant, because it says that Oliveira's advantage, which is now even greater than it was in London 2012, comes not from stride length, but the other important factor - stride speed.  It is the turnover of his limbs that separates Oliveira from the rest of the world, and which has made him a realistic medal chance in able-bodied competitions.

And why is that important?  Well, it closes the loop, bringing us full circle, because the scientific research on Oscar Pistorius showed that the advantage of double-amputee athletes, as a result of super-lightweight carbon fiber blades, is that his limb repositioning speed was "off the biological charts".  Those words were written by Prof Peter Weyand, who tested Pistorius and suggested a 10-12 seconds advantage because of limb reposition times he had never seen before, even in 100m Olympic champions.

Simply, the double-amputee was able to move his limbs so fast that he could then afford to spend more time on the ground, and generate significantly lower forces than able-bodied runners who were going the same speed as him.  The "athletic limit" to sprinting, according to Weyand, a world leader in sprint mechanics, is the ability to apply huge force to the ground.  Pistorius was able to run world class speeds without that limit existing, because his ultra-lightweight limbs allowed him be break another limit - the speed with which the legs could be moved.

Alan Oliveira has taken that to a new level.  When a man is running a 200m race and his strides are about 10% shorter than his rival's, then the only way to run faster than the rival is to have stride speeds that are 10% or more faster.  That's the Oliveira advantage - extra-ordinary speed of leg movement.  He is able to capitalize on the technology more effectively than any runner before him, and may also be able to generate force more rapidly than his predecessors.  The result is less time on the ground, less time in the air to reposition the limbs, and 20.66s and 10.57s performances.

Oliveria - validating the theory, vindicating the research, with no end in sight

Oliveira is, simply put, the validation of scientific theory, and he vindicates the predictions made about what would happen when the pool of athletes with access to carbon fiber blades expanded to include superior athletes.  This was inevitable - it's a rapidly growing sports category, and this is a great thing.  If only they'd kept them separate based on objective evidence, rather than the emotion of the Pistorius case.

Oliveira will one day be beaten by the next generation of double amputee, who will be even faster, and will then re-ignite the same debate.  The problem for the IPC and IAAF now is that they will have to reassess their guidelines in order to slow the runner down.  In other words, Oliveira is too fast, so we have to rewrite the rules.

Effectively, what they would be doing is setting a bar, at say 20.50 s for a 200m and 45 s for a 400m, and saying 'We welcome your participation, but just don't be too fast, or we'll have to change our rules to make you slower'.  It is analogous to putting weights on the bicycles of the top men of the Tour de France, to make the race more competitive, or make Djokovic and Murray play with wooden rackets to slow their dominance of tennis.

Well, the end is not in sight, because just as Pistorius was not going to be the pinnacle of athleticism on prosthetics, why should Oliveira be?  This is progress.  It's human progress.  A normal progression of ability as better athletes emerge.  The IPC and IAAF are looking at the technology, when they should be looking at how the heck they managed to duff the case against carbon fiber blades in the first place. 

Final word - a lot of the above discussion revolves around the very basic analysis of the London 2012 200m final, where I counted the strides for Pistorius and Oliveira.  What should happen is a similar discussion, in even more detail, now that Oliveira is rewriting the record books.

However, that won't happen, because the powers that be don't seem to recognize the importance of gathering the data to inform this kind of discussion.  I can appreciate that they have bigger issues, and may not have the resources to do it themselves.  Certainly, they are custodians over more than just one category and three of its events.  

However, in the build up to the Lyon IPC World Championships, I tried to approach the IPC for permission to analyse Oliveira's 100m and 200m races.  I wanted split times at 10m intervals, so that we could discover just how much time he lost at the start, when he hit top speed and how that top speed compared to Usain Bolt's (I suspect it is the same, or faster).  However, the IPC were not as enthusiastic, and so the study concept was never approved.

What a pity, because now we have to guess - we don't know his leg length, or the limit, or just how he put those world records together.  In time, maybe this debate will force those facts into the open, and that will be a good thing.  But until the evidence emerges, we talk about average stride lengths and stride speeds, which suggest that it's not solely about longer legs (as the public and even some rivals are still proclaiming), but about stride speed.

The evidence is out there, waiting to be found.  For Pistorius, the evidence was found - it showed clearly what was happening.  Why is it paid no attention?

In time, perhaps it will be.  Today, in 10.57s, Oliveira guaranteed that it would be.  There's much still to learn.

Ross