Human Limits

Today, I want to do a little more on the genetics of elite athletic performance.  A couple of days ago I briefly reviewed the genetics of height.  The bottom line is that while 80% of height is heritable (runs in families); it has been very hard to figure out the genetics of height.  Hundreds of gene variants with very small effect sizes contribute to height and when all of these genes are considered the consensus among the statisticians is that somewhere between 5-20% of the variation in height can be explained by simply “reading” differences in the genetic code.

What happens if we zoom out and think about athletic ability in general and what makes an Olympian or even an Olympic champion?

1)   To be a champion at anything you have to practice, practice, practice and this has been popularized as the 10,000 hour rule by Malcolm Gladwell in his book Outliers.   10,000 hours is a debatable number but the idea of practice and commitment is not.

2)    Like height the genetic components that make up what might be called ‘talent’ have been really difficult to decipher.  How various gene variants that might give someone an edge in some element of the mental or physical aspects of a given sport remains mostly a mystery.  Jonatan Ruiz and colleagues have some ideas about the perfect genotype for endurance sports, and it is really rare.

3)    Remember the role of environment and culture.  Based on their success in distance running one would guess that the Kenyan and Ethiopian tribes that dominate distance running might also do well in cross country skiing and endurance cycling.  However, we will never know until it either starts to snow in East Africa or the roads there get good enough for cycling to take off.

4)    Success runs in families.  So does early exposure and access to coaching and perhaps a competitive environment at home.   Early exposure also starts in East Africa as young kids run to and from school and play soccer at high altitude all day long.

So, success in sports is multifactorial.   Ross Tucker and Malcolm Collins have come up with a model that explains how a bunch of these things might interact.  I don’t agree with every element of their model but it is a good start.   They also offer an excellent critique of the 10,000 hour concept.

Along these lines, in elite competition like the Olympics, the margin of victory is tiny and there is no way we can measure any variable in the lab accurately enough to predict who might win by less than 1%.   If you ask me for a rough guess I will tell you for most sports, 80% or more is about practice and commitment and that means that almost any young person has the physical ability to get really good at something (say breaking 3 hours for the marathon or becoming a low handicap golfer).  However, the closer you get to truly outstanding the more important that ill defined thing called talent is, and the less we understand about the genetics of it.

Finally, it is pretty clear that we are a long way away from a blood test to identify which child might do well at what.  Practical approaches like considering body size, measuring vertical jump, running various distances for time, tests of strength, and tests of coordination are probably a much better way to go.

Then there is the equally complex matter of the psychology of desire and commitment…..

Today’s post is a bit more technical.

During the first week of the Olympics gymnastics and swimming will be two of the featured events.   I get a lot of questions about how much of elite athletic performance is due to genetic factors and how much is due to environmental factors: the classic problem of nature vs. nurture.

So why not start with gymnastics and swimming.   Gymnasts tend to be short and swimmers tend to be tall.   In the case of gymnastics it is important to have a high strength to body weight ratio.   A major factor that determines the strength of a muscle is its cross sectional area.

As people get taller the cross sectional area of their muscles gets bigger and they get stronger.  However, their body weight (essentially body volume) goes up faster.  Area is essentially a squared function of height and volume a cubed function.  There is a whole area of biology called allometry or scaling that considers these relationships for all sorts of things.

The practical effect is that as people get taller on average their strength to weight ratio gets lower and that makes it harder to do all of the tricks that the top gymnasts do.   This is one of the reasons that the top women in gymnastics have gotten younger and as a result shorter and lighter as the tricks required to compete at the highest level have gotten harder.

In 1968 26 year old Vera Caslavska dominated women’s gymnastics at the Mexico City Olympics.  She was reportedly 5’3’’(160 cm) and about 128 pounds (58 kg).  Caslavska, a Czech, was also a hero in resisting the Soviet invasion of Czechoslovakia in 1968.

Watch this video of her and compare it to what you will be watching on TV during the next week.

In swimming, a bigger surface should slow things down and make it harder to move through the water.   However, streamlined body positions like that seen in the Michael Phelps video posted yesterday, can limit the negative effects of size.  Swimmers are also in the water and essentially floating so there isn’t much penalty for getting heavier.

This general line of reasoning also applies to oxygen transport systems and when you add that to more muscle strength, taller swimmers have an advantage.  In general smaller people do better in things that are weight dependent and taller people do better in things that are weight independent.  This is especially true in endurance sports.  Compare the size of the distance runners with the swimmers and rowers you will be watching over the next couple of weeks.

So how much of this is “genetic”? It is known that height is about 80% heritable and there are excellent equations that use parental height and other factors that are pretty good at predicting the adult height of children.   However, at this time, there are no clear genetic explanations for why some people are tall and some people are short.  This has been studied extensively in hundreds of thousands of people and no answers have emerged.

I am attaching a link to a summary article on this topic and also a recent scientific article.   One idea is that as we learn more about how genes are turned on and off and how they interact with environmental factors the genetics of height will become clearer.  The other idea is that so much of what and who we are is so complex that there will never be clear genetic answers for most of it.

Yesterday I wrote about how elite athletes have an ability to focus and relax while at the same time putting forth great effort.  In skill sports like golf or hitting a baseball this is a version of Yogi Berra’s classic quote “how can you hit and think at the same time?”

This concept was stated more elegantly a couple of days ago in the NYT by the great Ichiro Suzuki about his first at-bat (he got a hit) at Yankee stadium after being traded to the Yankees.  “My 11 1/2 years here is a long time and I was thinking what I would feel like in my first at-bat, I really didn’t think anything. Nothing came to me. It was just a wonderful day to experience that.”

In sports associated with fatigue no one is better than Michael Phelps at keeping his rhythm and form at the end of a race.  There is an incredible video of Phelps swimming freestyle that shows just how skilled he is.

Terry Laughlin, the Total Immersion swimming guru, has a number of ideas that can help us all learn to do what Ichiro and Phelps do so well.   There is also a great interview by Amby Burfoot of Kim Conley who ran a perfect race to make the U.S. Olympic team in the 5k.  Her story exemplifies the Relax and Win approach.

Today we shift gears from doping and focus on the positive.

Willie Williams was my head track coach at the University of Arizona in the late 1970s.  Coach Williams had been a great sprinter in the early 1960s at San Jose State where he was coached by the legendary Bud Winter.   Coach Williams frequently encouraged people to relax instead of simply trying harder.  Where did this come from?

It came from Bud Winter who had developed a philosophy of high level performance that can be summarized as “relax and win”.   Some of this had to do with specific form and technique drills he advocated, and some of it was about a mental approach to competition.  It also has striking parallels to the psychological concept of Flow.

Nose around budwinter.com and you will get some insight into Winter’s approach.  There is also a video of him at practice conducting his iconic form drills.

During the Olympics we are going to see many examples where the margin of victory will be incredibly small.  In many of these cases, the winner will be the athlete who can retain their focus, form and rhythm when their whole body essentially feels like it is on fire.  In 2008 Michael Phelps was the poster boy for this.

This concept was also covered by Mary Pilon in the NYT in a recent series on 400m runner Amantle Mashto.  I was also struck by another piece by Mary in the Times on Wesley Williams, a superb blind long jumper and how committed he must be to the type of relaxed focus taught by Winter.

The question for us all is how to apply these concepts throughout the day.

Recent posts have focused on how elite endurance athletes might be manipulating their red blood cell counts to get a competitive advantage.   About 10 years ago I did a brief article that provides a scientific explanation for why blood doping and EPO work.  The article is still current.

In my 7/22 post I also expressed optimism that the biological passport system might be able to keep doping in check.   My colleague Ilkka Heinonen forwarded a link to a recent paper that paints a less optimistic picture.

While we are on the topic of EPO, there was a major expose in the Washington Post on the overuse of EPO to boost blood counts in patients with anemia.   The story points out that the development of EPO was a major breakthrough in biotechnology and a triumph of converting basic research into improved clinical care.

However, like a lot medical innovations, overuse is a problem and a major driver of health care costs in the U.S.  The best estimate is that about 30% of medical care costs have something to do with use of technology in ways that do not improve patient outcomes.

No matter where you are on the U.S. health care reform debate, the issues related to technology overuse need to be addressed.   During the next few weeks I will be focusing on the Olympics, but let’s not forget the real world while we are at it.

The Tour de France ended today and the Olympics will start in little less than a week.  My first two posts have been about doping in cycling and I thought it might a good time to look at this issue more broadly and ask if doping control can work.  This is a complex issue with differing interpretations of the same data.

1) There are a very limited number of positive tests.  Some argue that this is evidence that drug testing is working.  Others argue the tests are beatable and the limited number of positive tests prove the point.  In 2008 Joris Delhanghe and I wrote an editorial in the Journal of Applied Physiology related to testing for EPO and took the position that the tests are beatable.

The doping control agencies also seem to acknowledge this because a number of individuals who have been banned passed numerous tests and people can be banned with “non-analytical” evidence.  If the tests are so great who needs non-analytical evidence?  The best example is Marion Jones, one of the stars of the Sydney Olympics who was later banned and spent time in prison.  The bottom line is that the tests are beatable and the limited number of positive tests doesn’t tell us much about how well doping control is working.

2) Another argument is that performances are continuing to get faster and when large databases from elite cycling are considered increases in the average speed since the early 1990s “question the role of extra-physiological parameters in this recent progression.”  However, there is more recent data showing that things are slowing down suggesting that doping control might be having an effect.

Analysis of power outputs during climbs in the 2012 Tour suggests this is true.  A newer analytical approach to testing is the so-called biological passport which tracks blood parameters that might be altered by doping over time and looks for suspicious changes.  While this approach can’t ensure that doping isn’t happening, it may be able to level the playing field and keep excessive values for a number of factors related to performance in check.

In summary, this is a very complex topic with enough information, controversy, and angles for several books!  However, at least for EPO and drugs designed to improve oxygen transport there is some evidence that the biological passport is keeping doping in check.  However, doping is a cat and mouse game and there are a host of innovators out there who are looking for next best undetectable compound to use for an illegal edge.

During the Olympics I will focus on specific events to highlight issues related to human performance and focus on the factors that have led to improved records over time.

Note: when possible I will link to full copies of scientific papers.  If this is not possible due to copyright and access issues the links will be to a summary of the article of interest.

As noted in the first link below, Frank Schleck “withdrew” from the Tour de France after a positive test for a banned diuretic.  Diuretics have been used as “masking” substances to help beat routine testing for performance enhancing drugs.  They work by increasing urine output and can help “flush” banned substances out of the body or make the concentrations in the urine more dilute and less detectable.  Diuretics themselves would not improve performance.

In chatting with my colleague Dr. Alejandro Lucia from Spain, a leading expert on the physiology of cycling, current rumors suggest that a new class of experimental drugs that increase production of EPO are the next big thing in the peloton.  I am attaching links to a Washington Post article on the Schleck incident, a scientific paper on the new class of drugs that boost EPO production, and a paper by Dr. Lucia on the physiology of the Tour.

Recent news reports about the ongoing Lance Armstrong doping investigation raise some interesting issues.

The arguments that Mr. Armstrong was a serial doper go something like this:

• Doping was endemic in cycling, and there is no way he could have been so dominant for so long when the competition was clearly doping.
• Testimony from former teammates about systematic doping on the Armstrong-centered teams.

The arguments that Mr. Armstrong is clean go something like this:

• He passed an extraordinary number of doping control blood tests.
• At least for now, no trails of incriminating cell phone, FedEx, and/or financial records have emerged suggesting a series of suspicious transactions with suspicious people.

We know from the Marion Jones case that it is possible to beat the testing system, and that in many cases those who advise elite athletes about doping are one step ahead of the enforcement technology. We also know that many high-profile doping bans have centered on non-analytical findings, such as paper or electronic trails of suspicious transactions.

Now there is a report in the NY Daily News that offers a glimpse into data from blood tests that might be incriminating for Mr. Armstrong. The article reports that over a period of a couple of weeks in 2009, Mr. Armstrong’s hematocrit, an index of the ratio of red cells to plasma in the blood, increased by about 19% — from 38.2 to 45.7.

While that is certainly interesting and could be associated with EPO use or blood doping, it is well-known that hematocrit can vary widely on the same day in the same person.

Hematocrit variability

A 2005 study, Postural Pseudoanemia: Posture-Dependent Change in Hematocrit, shows that with just 30 minutes of standing, hematocrit can increase by an average of 11%, but by as much as 25%, as water essentially leaves the blood vessels and the red cells remain. There is also a 3-5% test-retest variability on the same sample from the same person.

Also, in addition to posture, hematocrit can be influenced by:

• Time of day
• Hydration status
• Recent exercise
• Use of a tourniquet during collection
• Variability when samples are run on different machines in different labs
• Altitude exposure

The bottom line: If this is the most incriminating biological data that the USADA has on Mr. Armstrong, it will be a piñata for a smart lawyer.