Science of Sport hits YouTube: The video concept

The Science of Sport on YouTube: Home ground advantage video presentation

Today is the launch of something we've planned for a long time, and that's to bring you The Science of Sport on YouTube, and in video on the site.  We've been trying hard this year to expand our reach and now have Facebook and Twitter accounts where some of the "quick-and-easy" and spillover content and discussion goes, but YouTube allows us to use video to literally talk to you about The Science of Sport!

Video lends itself to communicating sports science quite effectively, and so what I'll do as regularly as possible, is create videos of the topics that we cover on the site, usually in presentation form, and then link them via our YouTube account, as well as post them on the website.

It doesn't mean an end to the written posts, so those who enjoy a read on the train or at their desks, don't worry - there's no cutback in the pipeline!  But from time to time, mostly because I do quite a few presentations on Sports science to the public and in the academic world, it will create a more personal platform if we can use video.

Home-ground advantage

So, to kick off, a video presentation of our Home-Ground advantage series.

There are three videos in total, each 8 to 10 minutes long.  Part 1 deals with the concepts of home-ground advantage, Part 2 with the stats from Super Rugby, and Part 3 the travel factor.

Just a quick note - if you are reading this as an email because you subscribe to our email service, you may find that the YouTube clips either don't appear or come out as black blocks.  If that happens, click HERE and you'll go to the website where you can watch the clips

Part 1: Home ground advantage concepts and theories (9:05)



Part 2: Home ground advantage in Super 14 Rugby - who is in the fortress, who is in the shack? (10:54)



Part 3: Going overseas and the effect on home ground advantage (7:36)



To the future, and the Tour de France, the issue of Talent vs Training (I am giving a presentation at the Sports Science Institute of South Africa on this on Monday August 1st), pacing strategies and any other topics, look for more of the same!

Enjoy Wimbledon!  Enjoy the start of the Tour!

Ross

Home ground advantage: International vs local differences

Home ground advantage: The effect of international travel on performance

So today is the third and final installment in the series on home ground advantage, and it's going to be a visual and quicker to read one (promise!).  That will be followed tomorrow by a video recap of the whole topic of home ground advantage, which will also be the "world debut" of our Science of Sport Video series (but more on that later), and then we hit the 2011 Tour de France for three weeks of hopefully great, and interesting (and dope-free), cycling.

In the previous post, I looked at the size of home-ground advantage in Super Rugby, and my (admittedly) brief analysis showed that:

• Home ground advantage exists - 61% of matches in the Super 14 were won by the home team
• The odds of a team winning an away match were 0.64 times lower than the odds that they'd win the home match (eg: If the odds of winning at home are 80%, then the chances of winning away are 52%)
• Home ground advantage is worth 9.5 points.  This is calculated by looking at all home records and comparing them to all away records.  On average, teams win by 4.8 points at home, but lose by 4.7 points away, and so home ground advantage is worth 9.5 points
• The teams with the strongest relative home advantage are the Lions, Cheetahs and Brumbies.  The teams with the weakest home records are the Stormers and Chiefs

The travel factor: As yet just out of reach, but international vs local analysis sheds some light

Now, what we need to consider is how travel might impact on this.  I'll say upfront that this is a question I'm going to pursue in much more detail in future.  The data I have so far don't allow me to answer the specific question about travel...yet.

However, what we can do, using historical records, is look at the following two questions that get indirectly at the issue:

1. "What is the probability of the away team winning a match in its own country, compared to winning a match outside its country?"  
2. "What is the size of the home ground advantage when a team travels away WITHIN its country compared to playing an away match overseas?"

In other words, there are two types of away matches in Super Rugby - those where a team plays a LOCAL opponent (the Johannesburg-based Lions travel to Cape Town to play the Stormers), and those where a team plays outside its country (the Lions travel to Auckland to play the Blues, for example).

Limitations

These questions are relevant because they allow us to start seeing what the effect of travel may be.  Two limitations to the above questions are important.  First, this method doesn't allow us to see the acute effects of time-zone changes, because teams play those away matches for four to five consecutive weeks, so you have to include "time on the road" as well as travel.

Also, there are scenarios where being the home team still involves travel.  Imagine, for example, that the Lions have just played four away matches in Australia, and then fly back to South Africa to play the Bulls.  In that case, the Lions are the traveling team, even though they may be at home against local opposition.

This is a level beyond the analysis I've done so far.  However, as I said, I'll definitely look at it in future.  The results I present below thus only answer the question of "International vs Local" matches away from home - it's an indirect measure of the travel effect.  It's also a relatively small data set - with time, I'll build it up and go back many more years to strengthen it.  However, I think it reveals some interesting truths, but it's by no means final!

So let's look at those "truths"...

The odds: How likely is a team to win outside its own country?

So, the main implication of the above figure:

• Home-ground advantage is considerably lower when you play against a team from inside your own country - the home team then only wins about 54% of matches (remember, the tournament average is 61%).  The odds of winning away are 0.85 times those of winning at home - not bad at all.
• When a team goes overseas, the home team wins 64% of matches. Now, the odds of winning away are cut in half compared to winning at home.  
• There, winning away matches outside your own country is far LESS likely than winning them in another country - home ground advantage counts for more when the visitors must travel internationally
• I repeat the stat that says that since 2000, no team has won a knock-out match having had to travel to another country.  That may change this weekend, but it's 0 from 34 now, and that says a lot

To repeat, this doesn't mean it's exclusively due to travel (it may be "homesickness" if a team spends a full 5 weeks on the road).  And there are matches in the above data set where the traveling team is actually the local team, as I mentioned above.  But overall, it says that playing overseas has a significant effect on the likelihood of a team winning.

The size of home-ground advantage against local and international opposition

Next, we take the same approach I did yesterday, looking at every single team's home and away record to see how large their relative advantage is when playing at home.

First, the figure below shows points differences and average scores for all teams when playing against LOCAL opposition (from the same country) either home (top) or away (bottom panel):

So, you can see that most teams have winning records at home (green bars) and losing records away (red).  The black rings show examples of teams with winning records both home and away, while red rings show losing records home and away.  Some teams, like the Reds (see arrows) have a winning record at home, but lose away.  The difference between the home points difference and the away points difference is the home-ground advantage, but I'll get to that shortly.

Next, we look at the same 14 teams, this time home and away against international opposition:

Once again, some teams have winning records both home and away (like the Crusaders, ringed in black), while others lose both.  Interestingly, only two teams have winning records outside their own country.  It's quite clear from these two graphs that the average result being overseas is worse than being away within your own country.  And the red rings this time indicate the more common pattern - a winning record at home, but a losing one away.  For example, the Brumbies average a 27 - 20 win at home, but a 17 - 24 loss away.  Again, the difference between these two will tell us the value of being at home.

That value, the "home-ground advantage" is summarized in the graph below.

 

So, the top panel shows the relative home-ground advantage when playing against LOCAL teams, the bottom panel the advantage when playing international teams.  Bizarrely, the Bulls actually perform better away from home against local teams - if you go back up to the first figure, you see that their home record against other SA sides is a 23-21 win, whereas their away record is a 29 - 19 win.  I'm pretty sure there's nothing in this - it's the reason why the dataset needs to be expanded.  But they are the exception - all other teams far better at home against local sides.

Similarly, against international sides, everyone but the Chiefs do better at home against international teams.  You'll recall from yesterday that the Chiefs actually have the lowest home-ground advantage - this is why - they average a 3 point win at home, a 2 point win away (the error is due to rounding up/down).

However, the real significant fact is this:

• Average home-ground advantage when playing against local teams is + 6.3 points
• Average home-ground advantage when playing against international teams is +10.8 points
• Therefore, home-ground advantage is increased when playing international teams.  To the tune of 4.5 points, which is the value I would attribute to "geography", in the sense that this is what it shows.  This is summarized in the graph below.

Once again, I must stress that this is doesn't accurately quantify the effect of travel, but rather of playing internationally or locally, and it uses a small sample size. To get the full value, one needs to a) go back further, all the way to 1996, and b) track results as a function of local or international travel, time away from home, direction of travel and home-ground advantage.

But it does start to indicate that the travel is a burden on teams in Super Rugby.  That being away from home, the probability of winning matches is much lower when you are overseas than in your own country - perhaps this is travel-fatigue, perhaps it is culture-related, perhaps it is related to home-sickness and motivation.  Whatever the reason, the early results suggest an affect.  Once again, I'd stress that this competition is unique in this regard.  Factor in the altitude (for some teams) and Super Rugby may have a lot to teach us about home-ground advantage!

All in good time, of course! That's a lesson to resume again in the future!

The Tour de France:  Three weeks of cycling coming up

And it's a wrap for home-ground advantage.  I realize that maybe the rugby focus was not relevant for many, but as long as it inspires some thought, thank you for reading!

The Tour de France is up next, and it's going to be all systems go!  The race starts this weekend, and you can expect analysis and thoughts as the race unfolds.  If there are any specific questions, or information, or power output values, or anything else, please don't hesitate.

The Video Series, launch imminent

And finally, an exciting (we hope) announcement.  Our main objectives with The Science of Sport are to share our insights and opinions (we mouth off on sport and science!) and to communicate scientific concepts, usually as applied to sport. The key is communication.

And so, we are always on the lookout for ways to improve how we communicate science.  That's why we created the Facebook page and our Twitter feed, so that we can provide links and thoughts more consistently than time allows us to post here.

But, one avenue we've never explored is video.  The thinking is that video lends itself to communicating science more effectively.  It's graphic, and we can talk through concepts rather than write them.  Maybe it's also more personal. 

And since we do a great deal of speaking and presentations (Ross in particular, being in an academic environment), we thought it a good idea to start publishing videos of our presentations and the topics we cover on this site!  That we, we can talk through ideas, and maybe condense your time a little.  We'll still keep going on the writing, don't worry, but the video hopefully brings an added dimension to the Science of Sport.  Please share and distribute!

The videos will go up on YouTube, they will be embedded here. We start with a video of a presentation on Home-ground advantage (which I will give internally at the Sports Science Institute tomorrow).  I know it's not a topic that many of you will relate to, being about rugby, but it's a start and in the future, I think we'll try to do this much more often, for topics ranging from the Pacing Strategy talk to Talent and 10,000 hours.

That will come shortly, let us know any feedback and how we might improve on our mission!

Ross

Home-ground advantage in sport: Theories

Home-ground advantage - theories and stats, Part 1

***Click here to see Ross of The Science of Sport talk you through home ground advantage in three video presentations, covering the theory and the stats.***


This past week in South African sport was punctuated by, among other things, a discussion around travel and the effect it has on professional sports teams.  The specific subject was the Sharks, a professional rugby team from South Africa, who flew to New Zealand for a playoff match in the Super 15 Rugby competition.  That discussion has turned out to be a nice catalyst for a couple of posts on home-ground advantage and the factors driving it (Part 1), followed by a post by Tuesday on travel and some interesting stats on how Super Rugby is influenced by both factors (Part 2).

Super 15 - an extreme model to study home-ground advantage

The Super 15, for those not in the rugby loop, is a tournament played between professional teams from South Africa, New Zealand and Australia.  It is now two weeks from its conclusion and is into the playoff phase.  The vast distances that are required, as well as the altitude for some teams in South Africa, make it a really great model to study home-ground advantage.  In fact, I'd go so far as to say it's unique in this regard, in that it has extreme travel (10 time zones a trip) and large changes in altitude (0m to 1600m) on a weekly basis.  But more on that next time...

Of course, travel is only part of the home-ground debate, but for the Sharks, it was the big one - they decided to leave South Africa on Tuesday, four days before the match, and so arrived, 10 time zones to the east, with only 2 days before a huge match.  The question then was whether it would be possible for the players to recover and perform optimally?

I thought it was pretty certain that they would not, which I said in the article.  Turns out they lost, 36 - 8, which is a pretty heavy defeat at this stage in the competition when you consider it's between the best of the remaining teams in the playoffs (3rd vs 6th in this case).

Of course, it would be an enormous oversimplification to say that the loss was due to travel fatigue, because sport is way too complex to reduce to one variable.  However, I think it probably played a part, particularly at the end of a long season and after some very physically demanding matches in the weeks before.

What wasn't quoted in the article was that I was of the opinion that the match would be very competitive for the first 30 to 40 minutes and then the scoreline would blow out.  The Sharks probably needed to be 10 points ahead with 20 minutes to play, because fatigue would influence performance more later, whereas motivation would "hide" it for a while, before it eventually told.  That fits with what eventually happened - it was competitive half-way, and the big defeat was inflicted in the second half.

Zero from 32 - the challenge of travel in Super Rugby at the end of the tournament

How big is home-ground advantage in the Super Rugby competition?  Well, consider that since 2000, not a single team has won a playoff match outside its own country.  That's 11 years, and thirty-two matches (they have playoffs and semi-finals), and not once has an international away team won.  Admittedly, part of this is because the home team is at home precisely because in the course of the season it has been better than the visiting team, but still, zero from 32 in a competitive tournament is a telling stat for how difficult it is to travel overseas in the final few weeks of a four-month long tournament.  

The main reason for that, I'm convinced, is travel, but I'll talk about travel in the context of Super rugby in Part 2 later this week.  First, let's look briefly at the science of home-ground advantage.

Home-ground advantage - consistently 50 to 70%

There is no question that home-ground advantage exists.  This article presents some numbers from US-sports, saying that in basketball, the home team wins 62% of matches.  In baseball and ice-hockey, 53%, and in the NFL, anything between 54 and 64%.  There is some evidence in football (that is, soccer, to avoid confusion!) that playing at home is worth 0.4 goals (1.5 vs 1.1 goal to home and away team over 5,000 analyzed matches).

For rugby, it's never been published, but I have done an analysis of the last five years of Super Rugby competitions (the format and number of teams changes every few years, so it's a shorter period) and in Super Rugby, the home team has won 61% of the matches they play.  If you break this down further into away matches against "national" teams compared to away matches internationally (ie: NZ side playing an SA/AUS side), then the figure is close to 80%, which is enormous.


You see the same thing, equally strikingly, when countries host international sports events like the FIFA Football World Cup or Olympic Games.  Medal hauls almost always increase at home.  There is a little more to this than simply competing at home, because the host nation almost always injects massive capital (human and financial) to improve sports performance, which is possible because countries know many years in advance that they are going to host.  So Olympic hosts perform better, but it may be due to increased spending to prepare athletes, in addition to the factors I'll discuss below.

Factors influencing home-ground advantage

This is a somewhat simplified summary of what we know, but generally, there are four factors influencing home ground advantage:

1. Travel fatigue for visiting teams
2. Familiarity with the city, the facilities, the playing arena
3. Crowd factors, which can be further broken down into:
1. How the crowd influence the players
2. How the crowd influence the referee/officials

As mentioned, I'll tackle travel tomorrow, when I talk about Super Rugby, so let's look at the others, in reverse order.

The crowd influence on officials - a subconscious bias

Starting with the referees (a favorite of sports fans everywhere!), there is a real perception, true or not, that visiting teams are often ‘robbed’ by referee decisions. It turns out this is not a perception without some merit.  Studies have found, for example, that visiting teams in ice-hockey and basketball concede more penalties and have more players sent off for foul play than the home team.

It's also been found that the discrepancy in penalties awarded to visiting and home teams increases as the crowd increases in size.  And that when two London teams play football against each other, thus reducing the "unevenness" of crowd support, the discrepancy is reduced, suggesting that this may be the influence of the crowd on the referee. Even the most neutral and professional referee, with no intention of cheating can be swayed by the cheers or boos of a crowd.

For example, one study had football referees make judgments based on video footage of obvious foul play, but some refs watched without sound, while others watched with full sound, including crowd reactions to fouls. It turns out that with the sound, the referee is more likely to be swayed towards what the crowd is calling for - fewer free-kicks to away teams, more to home teams, no foul when the home team is guilty.  This is summarized in the figure below. And this is just on a TV screen, away from the cauldron of pressure of real-time action, where the crowd may have even more influence.

Further supporting this idea is that in the Olympic Games, the host country often wins significantly more medals, but most of them come in the subjectively scored events (ice-skating, gymnastics etc).  Given the football referee study, it's not difficult to see how a rapturous cheering crowd might be worth half a point here and there to a judge, despite their best efforts to block out crowd factors!

I must point out that there is other possible reasons why visiting teams are penalized more. One is that the "hostile environment" of the away arena produces a “victim” or “us against the world” attitude that sees visiting teams play more aggressively than they would otherwise.  This has in fact been documented for visiting teams, and, on occasion, for home teams, depending on the context of the match and the crowd behavior.

Also, the home team is often more aggressive and dominates play (defending their territory, perhaps), forcing the opposition to concede penalties as a result of applied pressure.  One analysis of decisions in the NHL found no difference in mistakes between home and away teams, suggesting that the penalty discrepancy may be justified (I am not quite sure how to reconcile that with the football study above, where the refs were making different judgments of fouls simply because of sound...)

Crowd influence on players - motivation, desire and anxiety

Harder to measure, but possibly as significant, is the effect of crowd support on player motivation and effort.  Certainly, sport is filled with testimonies of players who find "something extra", who raise their level because they're at home.  I guess one needs to be careful about taking a collection of testimonies and saying they are evidence (the plural of anecdote is not evidence!), especially because linking these factors to performance is very difficult.

But there's no question that "psychology" (an incredibly broad term) plays a role in sports performance.  But the sword may cut both ways when it comes to home-ground advantage.  A visiting team, with the odds against them, may well perform better than at home because of the desire to silence the crowd, and because of the added prestige of beating a team in their own country - I've experienced this with the SA Sevens side.

On the other hand, the effect of the crowd and the momentum they may give to players (who, for all the talk of "zoning the crowd out" must surely be aware of it) may be decisive - I have also experienced this with the Sevens team.  If you were to define a set of psychological requirements for success, you'd almost certainly put "confidence", "self-belief" and "high level of motivation" on the list, and in theory, that's what being at home brings.

To throw a curveball at that oversimplification of the theory, there was a fascinating opportunistic study a few years ago when a college basketball team had to play 11 of their matches behind closed doors because of a measles outbreak that forced the school to be quarantined.  It turned out that the team played better WITHOUT fans!  Their stats were up - more points, more free-throws and better shooting percentages.  Of course, 11 matches is a small sample when you consider how many factors might influence each performance outcome, but it does suggest that perhaps, fans influence players negatively, through increased anxiety.  Maybe the other team is just more anxious, and plays relatively worse!

Familiarity - 'no place like home'


The fourth and final factor, which is linked to the psychological factors I mentioned above, is familiarity with the playing venue, the weather, the training facilities, and also the people who the player encounters in the week leading up to matches.  There's some evidence for this too.

For example, in 37 sports teams who moved to a new stadium, home ground advantage fell by 25% in the first season at a new home (this is a small sample set, it must be noted, given the complexity of sports performance). The advantage still exists, but they are thus less likely to win at home than before.  Over time, this advantage returns.

Two things are in play here. First, they are no longer as familiar with their own stadium, and as trivial as it may sound, I believe this is a crucial aspect to performance, because it influences routine, focus, relaxation, confidence, and expectation prior to matches.  There may even be a more "primal" factor, in that the home team is protecting its territory, a theory that coaches play up all the time - the "our house" speech you may have heard a variant of!  New stadium, less territorial, less advantage?  Perhaps.

The second factor is that the visiting teams no longer have a potential psychological hurdle of entering the “fortress” that may have existed before.  This introduces the other side of the debate - the mindset of the visiting team.  In South Africa, we have a couple of rugby venues that are hostile to visiting teams, and knowing a few players, they don't particularly enjoy going there!  The media tend to hype up the fortress idea, and while players should in theory be able to resist this kind of intimidation, there's no question that mindset may be changed by the awareness of an away team.

In my experience, I actually feel that sometimes it is played up too much within teams.  Coaches and players always tell the media that it's still a game between two teams, a ball and four white lines, but they often create confusing internal messages, trying to downplay the mental aspect while simultaneously trying to inspire players to "be ready for the onslaught from the home team".  If any of this impacts the player, then home-ground advantage may have an effect through negative influences on the visitors.

Then there are also very specific factors - the Lehrer article talks about Boston's old basketball court with its uneven parquet floor and dead-spots, which visiting teams did not know about.  Weather conditions can influence this significantly (wind and rain adapted teams will thrive in their own conditions), as can pitch conditions (cricket is a big one for this).

In my experience, familiarity is a really crucial factor, perhaps the main one (though this is just my opinion born of my experiences with the Sevens side).  I believe it reduces anxiety significantly, and even allows players to find visual cues in the stadium that may help their performance.  Much of this happens away from the venue - it's in the hotels, the people, the food, the TV stations in hotels, the sights and sounds.  Just having family and friends around in the build-up is significant, provided it doesn't cause over-arousal.  The key is whether the familiar experience is a positive one or not.  Positive experiences are easy to reinforce, and so a player will be more optimistic, more confident when playing at home.

Experience counts - reducing home ground advantage?

This is why experience is such a vital factor for success in tournaments away from home.  Later this year, the Rugby World Cup takes place in New Zealand, which has historically been an incredible place to win.  There are a number of reasons for this - New Zealand has historically been the world's best team, so really, they'd be difficult to beat anywhere.  But the weather and travel distances don't help, and nor does the psychological block that teams take with them when they go there.  Positive experiences erode these factors, and so teams who want to succeed, will, I believe, have to rely heavily on players who have been there, won there, and know the stadiums, hotels and people.

Whether or not any of the above factors translate to better performance, I don't know, but I guess the bottom line is that playing at home CAN bring what sports psychologists recognize as crucial to optimal mental performance.

But then again, it's still four white lines, a ball and the same set of rules!

Travel

The factor I've left out is travel, and that's because it's worth a post of its own, especially given the Super 15 motives behind this post.

That comes tomorrow, so join us then.  Also, don't forget to get on Facebook and Twitter if you're on them - I try to use them as a supplement to the site, posting some thoughts, opinions and links to articles of interest.

Ross

Home-ground advantage: Super Rugby, travel and altitude

Home-ground advantage: The Super Rugby illustrations of travel and altitude

Yesterday, I did a post describing home-ground advantage in various sports, and looked at three of the four factors that may influence performance at home or on the road.  The plan was to tackle the effects of  travel on home ground advantage in part 2, using some data from the Super Rugby tournament.  But, once I began writing this post on the Super Rugby tournament, it was clearly a subject all of its own.

So rather than try to squeeze too much into one article, I thought it would be best to have a Part 3, where I will look at the impact of travel on physiology.  Of course, in Super Rugby, there is an additional factor affecting home-ground advantage, and that is the altitude (three teams - The Bulls, Lions and Cheetahs all play at 1,400m or higher).  But that too will feature in Part 3.

But for today, Part 2, I take a look at home-ground advantage in Super Rugby.

Home ground advantage in Super Rugby - travel and altitude effects?

I mentioned yesterday that the home-team has won 61% of the matches in the Super 14 competition, dating back 5 years.  It's possible to go further back, but the format has changed every few years, so we'll stick to that duration for now.  I analyzed every single result in the tournament and tried to tease out the value of home-ground advantage per team.  Of course, this is historical data - it would be wrong to apply it to 2011 teams in isolation, but it's interesting nevertheless. 

There are a three approaches to this problem.  The first is to take home performances at face value, asking how likely the home team is to win the match. This is certainly the most intuitive and practical approach - it's easy for commentators and analysts to look at the record books and say that "Team X has only lost once at home in 5 years", assuming that their home ground advantage is responsible.  This doesn't take into account the relative strength of a team, it merely looks at whether they tend to win at home or not.  

The second method is to start looking at RELATIVE chances of winning home vs away.  It uses win-loss ratios, and asks which team has a relatively better chance of winning away than others?  

The third approach is to look at more than winning and losing by considering also the points scored.  By factoring in points differences at home compared to away over a prolonged period, you get an idea of what being at home is worth, both to the results and the points scored and conceded.

Let's look at all three.

Method 1: At face value, who has the best home record?

First, the win percentages home and away for each team, grouped by country:

So, overall, the home team wins 61% of matches.  But some teams are clearly better - the Crusaders and Bulls, who have the best overall records (winning 73% and 65% of their matches), have won more often than they lose, both home and away.  Their home records are outstanding - the Crusaders win 9 out of 10 home matches, the Bulls 8 out of 10.  In contrast, the Lions and Cheetahs have won fewer matches at home than most teams have won away from home!  

Taken at face value then, the team most likely to be beaten at home is the Lions - they only win one in three matches at home, and so any team traveling to Johannesburg to play them is unlikely to hold much fear about the away match!  

In contrast, if you are heading to Canterbury to play the Crusaders, history suggests that you would not fancy the chances of an away win, because they win 9 out of 10 matches at home.  What is important to realize is that their home ground advantage is a function of both the strength of their team and their playing at home.  Both together make winning in Canterbury much more unlikely than winning in Johannesburg (Lions) or Bloemfontein (Cheetahs).

Method 2: The relative effect - odds of winning away RELATIVE to at home

But that doesn't mean that being at home does not give teams like the Lions some advantage, and this advantage may even be larger than for the teams that win!  The easiest way to understand this is to realize that if you are playing the Lions, it doesn't matter much where you play them, you're likely to win (they win less than a third of their matches, regardless of venue).  It just happens that they are more likely to be beaten away from home.  So the question should be relative (who is MORE likely to win away matches?),  rather than absolute.

So the key is the odds.  To illustrate this, imagine that home ground advantage did NOT exist - it was worth nothing to a team.  Teams would win 50% at home and 50% away.  Therefore, the ratio of away to home wins would be equal to one - you have an equal chance of winning, regardless of where you play.  If home ground advantage was enormous (imagine infinite), then the home team would always win (making this 100%) and the away team would never win (0%) and so the odds of winning away would be zero.  I have calculated an "odds away" ratio, shown in the far right column, which tells what the probability of winning AWAY is relative to winning at HOME.

In other words, the closer the odds away value in that column is to 1, the better the chances of winning away from home, and hence the smaller the home ground advantage for that team (put differently, it means the team "travels well", which is to say, their performance on the road is not much different to when at home).  

So, the teams with the best away records relative to home will have a higher "odds away" ratio, suggesting the smallest home ground advantage.  They have been the Force (who are almost equal, home and away), the Stormers, the Reds and the Waratahs.  To give a verbal illustration, the Stormers have an odds away ratio of 0.76.  This means that if the chances of winning at home are 100% (which is never true, but work with me!), then the chance of winning away is 76%.  This is much higher than the Cheetahs, who would have a 35% chance away from home.  If the chance of winning is 50% at home, then it's 38% and 18%, respectively.

So it's interesting that two South African teams, the Lions and Cheetahs, who play at altitude, enjoy a pretty substantial relative advantage at home.  Or, if you want to reword this, they are relatively much worse away than at home, possibly aided by the challenge of coming to altitude!  The Bulls, the other altitude based team in the competition, have a smaller advantage - they win 79% home and 52% away, giving them away odds of 65.4% relative to home.  It's higher, but certainly not the highest in the tournament.  They are a good traveling side - one of the few to win more often away than at home, and perhaps their greater ability away masks any altitude effect.

The New Zealand teams, interestingly, travel well (all have high ratios of away:home win percentages) and so to them, being on the road matters less than to the other two nations' teams.  Quite why the Force have such similar overall win percentages home and away is interesting.  It may be that a new team, they haven't yet established their "home territory", which makes their performances at home relatively weak.  In time, that home win percentage may climb and they'll come to resemble other Australian teams.

Let's look at points difference to consolidate this further.

Method 3, Points differences:  How much is playing at home worth?

The next approach is to look at how teams score points home and away.  The graph below is a summary of five years worth of Super Rugby matches, for each team, looking at their average scores both at home and away from home.

Here, green means a positive record (winning matches), red means losing matches.  Only three teams have had overall winning scores away from home, with two having tie-records.  Four teams have overall losing scores at home.  

Once again, the key is home relative to away.  Take a team like the Crusaders - they average a 31-14 win at home, and a 23 - 20 win away from home.  Best team, historically, in the competition.  This means that their home victory margin is 14 points better, on average, than their away margin, which is the size of the home ground advantage to them, in points.  In contrast, look at the Stormers of Cape Town.  They average a 4-point win at home, and a 1 point loss away, which means that home advantage is worth 5 points.  And finally, consider the Lions, the tournament's historically worst team.  They lose by 21 points when away from home, but by "only" 7 points at home.  This makes them the weakest home team in the tournament, in absolute terms, but relatively speaking, their home advantage is thus 14 points, similar to the Crusaders. I've shown the size of the home advantage for all teams in blue on the right.

There are problems with this approach, of course - teams don't play to score maximum points, they play to win and so a 21 point defeat and a 5 point defeat are not necessarily comparable as this method does.  Also, it needs many more years worth of data to become statistically meaningful because strength of teams changes and so to do seasonal variations in performance.

But, overall, it throws up some interesting observations.  As we saw for the odds-method above, the Lions and Cheetahs have very good home records, relative to away.  But they are still the weakest away teams in the tournament.  The Stormers, on the other hand, are not as good at home - their advantage is 5 points, and as we saw above, their odds of winning away are 76% of the odds of winning at home.  Overall, they enjoy a relatively smaller home ground advantage.

Interpretation of Super Rugby - large home ground advantage?

Yesterday, I received an email from a bookie who said that his stats (bookies have great stats on this because they use odds to calculate bets all the time) showed that in Northern Hemisphere rugby, home ground advantage was worth 3 points.  Taken together, the Super 15 data above have an average home ground advantage of just under 10 points.

So home ground advantage, at least in this admittedly small sample (blame the ever-changing competition format and my lack of time!), is greater for Super Rugby than for the equivalent northern hemisphere tournament.  This does not surprise me, and I believe it exists for two reasons:  Travel across time-zones and altitude at some venues.

Super rugby - a uniquely demanding competition

For these two factors, I think that Super Rugby is unique.  Consider the travel:  I am not aware of another competition where teams have to travel across so many time-zones so frequently with such short turnaround times (if you know one, let me know)  In US-sports, teams will occasionally travel across North America, a five hour flight across four time-zones, but this pales into insignificance when compared to multiple half-day flights across up to ten time zones faced by Super 14 teams. Perhaps the only comparison comes from Sevens rugby, where teams fly around the world three times in a five month period.  Tournaments like the World Cup or Olympic Games may of course involve big travel, but they last 4 weeks, and require no long-haul flights.

If you’re counting, it turns out that the cumulative change in time zones in Super Rugby is 38 time-zones for South African teams (with 4 to 5 consecutive weeks spent away from home), compared to 20 time-zones and 2 to 3 consecutive weeks away for New Zealand and Australian teams.

The greater time away from home is may be a factor – evidence exists that teams fare worse at the end of a long “road-trip” than at the beginning, but the issue of adapting to a new time-zone may be equally crucial for performance in the first week in particular.

I'm busy doing an analysis on this right now - it's hampered by the small size of the sample, but hopefully it will make for some interesting findings, which I'll try to discuss in Part 3 if the data look anything but chaotic!  One stat that I can't ignore is that in 11 years, and over 32 matches, not once has the away team been able to beat the home team outside of its own country in a playoff match.  It suggests a powerful effect of travel, because even though the odds should be stacked in favour of the home team, zero from 32 is a huge historical barrier to have to overcome.

Altitude effects - an advantage for some in SA

Then there is altitude.  Here again, the Super Rugby tournament is unique.  I don't know of another tournament where teams can play a match at sea-level, followed one week later by a match at altitude, then sea-level and then altitude.  That frequency of changes is unique - teams in US-sports play in Denver, a similar altitude to Johannesburg, but it's once off. Teams in Europe rarely travel to altitudes higher than 700m (Madrid, for example).

The altitude alone could create a significant home-ground advantage.  It is interesting to note that the Lions and Cheetahs are so much stronger at home than away.  That could be that they are terrible traveling teams, of course, but part of it may be that they benefit from the effect their altitude has on opposition teams.  

For more on the altitude, I will rather refer to the following three posts I did last year in connection with the Football World Cup held in South Africa:

1. The impact of altitude: What to expect from altitude and team sports
2. Performance implications of sport at altitude
3. Timing of goal-scoring, fatigue and altitude

Taken together, the combination of travel and altitude is a huge challenge for a Super 14 team.  Earlier this season, the Highlanders, a team from New Zealand, undertook the 10 hour time-zone change to fly to South Africa, landing in Johannesburg. They then played the Lions, at an altitude of approximately 1,600m, and then fly to Cape Town, and then back to New Zealand. In and out within two weeks, but with the dual challenges of altitude and travel.

More on travel

The travel issue is especially interesting.  Tomorrow I'll do a short post on travel and the role it may have on Super Rugby home-ground advantage.  It may be impossible to get anything out of the analysis I'm trying to do, because it may take decades and hundreds of matches, but we'll see!  So join us then!

Ross

The Sub 2 Hour marathon debate

The sub 2-hour marathon:  Science fact and projecting performance

I hate repeats.  Well, that is, I usually hate repeats, unless there's a very specific reason to watch the same thing twice.  And I figured that with the London and Boston Marathons only a few days away, there is no better time for a repeat than today.

The BBC yesterday did a radio show and carried this article on the possibilities of a sub-2 hour marathon.  The article is interesting and it touches on most of the points that we have looked at in the last few years, because this is by no means a new debate.  In fact, it seems to cycle around once every six months on the marathon-carousel.  Every time we have a big marathon on the horizon, people ask this question.

Personally, it seems a bit premature to me to be talking about a sub-2 hour marathon now, when the first human performance under 2:04 was as recent as 2008.  And then, by only 1 second!  To knock off another 240 seconds and break that barrier is getting a little carried away.  Let's get under 2:03 first, and then see how the future looks! That could easily take two generations of runner, another 10 years.  The big names are weighing in though - Gebrselassie and Radcliffe (who know a thing or two about marathon records) both suggest it will happen within 20 years.  A scientist predicts 28 years.  I suspect they're all a little optimistic...

The scientific merit - digging deeper

However, it is a question that has a great deal of scientific merit.  Both the mathematical modeling of performance evolution and the physiology of breaking 2 hours in the marathon are extremely interesting, and that's where the BBC article doesn't quite do justice to this question.

That is, the BBC touch on all the aspects - they mention the history, the evolution, the physiology that may be required, and the conditions that have to come together, but they varnish the surface rather than really getting stuck into it.  And so with that, I thought I'd take the opportunity to re-post an article I wrote about 7 months ago.  It asks "What is the physiology required for the 2 hour marathon?"  That article is below.

That article is below.  Also, the question is discussed from a historical point of view and using a slightly different approach to what you'll normally read in the media, in the following posts:

• Who will break 2 hours for the marathon?  And when?  Lessons from the shorter distances
• Why the marathon record was destined to drop, and why it may be about to level off again

Hopefully those three can keep you intrigued while I get my head around 10,000 hours and the next in the series on training and talent development!

Ross
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The sub-2 hour marathon: What physiology will it take? (originally published September 4, 2010)

The other day, I did a post looking at the likelihood of a sub-2 hour marathon, inspired by an interesting article published in the Journal of Applied Physiology.  That was part 1, focusing on the historical evolution of world records, not only in the marathon, but over shorter 10km and 21km distances, because I'm of the opinion that a 2-hour marathon will only be possible when the 10,000m times and half-marathon times improve by at least 30 seconds and 90 seconds respectively.  So, contrary to the JAP paper, which suggested that the barrier would be broken in between 15 and 25 years, I think it will take many, many more years.

Today sees the promised Part 2, looking more at the physiology, and specifically the running economy that will be required in order to reel off 42,195 m at an average pace of 2:50/km.  It's a conceptual post, so bear with the length and the "unanswerable" questions.

And I must emphasize the point, picked up by some of you, that physiologically, our ability to separate a 2:03:59 from a 1:59:59 is limited.  Both performances are close to the "limit", and given that elite athletes are rarely tested and measured in the laboratory, and that the physiological variability is larger than the difference in performance we're looking for, you won't reach the end of this kind of discussion with a concrete answer.  However, it's an interesting process, nonetheless.

Running economy re-introduced

Way back in 2007, we did a short series on Running Economy, the first post of which can be read here.  Running economy is a measure of how much oxygen you use when running at a given (sub-maximal) speed.  The more economical the runner, the less oxygen is used, and this is crucial, because it is a characteristic of great runners that they are much more economical.

The graph below, which is redrawn from a paper by Foster and Lucia (2006), shows the running economy of a few different groups of runners.

Here, running economy has been measured as the volume of oxygen used per kilogram to run one kilometer (think of fuel economy in a car - one gallon takes you x-kilometers).  So, the Europeans shown by the pink line in the above graph are using approximately 210 ml/kg to run 1 kilometer.  You can convert this to the actual VO2 quite easily, if you know the running speed.  For example, at 20km/hour, 1 kilometer takes 3 minutes, and so these European athletes are using 70ml/kg/min at that pace.

The Africans, shown in red, are considerably more economical (this is one of the more interesting debates in physiology - there are obviously overlaps, but generally, African runners appear more economical than Europeans).  The VO2 of the Africans at 20km/hour is equal to 190 ml/kg/km, or around 63 ml/kg/min, about 10% lower than the Europeans.

Can economy and capacity predict performance?

So, knowing this, we can begin to project what kind of physiology is required in order to run a sub-2 hour marathon.  The method used is very similar to that used for cycling, when we looked at the power outputs achievable during the Tour de France in our recent Tour coverage.

There are of course assumptions that must be made, but as I tried to explain for cycling, if you make the "conservative" assumptions, you still produce an interesting picture of what is physiologically plausible.  This is an exercise in theory, not proof.  It is the first word in a debate, not the last, so bear with some assumptions and let's see what the picture reveals.

The assumptions

The first assumption that you have to make is what relative intensity an athlete can sustain for a given period, two hours in this case.

This is not too much of a guess for elite athletes, but it does vary considerably with training - an elite athlete is usually able to sustain running speeds that require about 85% - 90% of VO2max for about one hour.  Marathons are usually run at an intensity corresponding to approximately 80% of VO2max, while 10,000m is run at around 95% of VO2max.

So for a two-hour marathon, we can make the assumption that the intensity will be equal to between 80% and 85% of maximum.

Next one has to assume VO2max, the "capacity".  This is more of a lottery, because the range, even in elite athletes, can be quite wide.  Zersenay Tadese of Eritrea was measured at 83 ml/kg/min, but some elite runners have been measured as low as 70 ml/kg/min (the reason they are still competitive, incidentally, is likely due to exceptionally good running economy). 

And then finally, you must assume running economy.  This is the key assumption, because as the graph above shows, it varies quite considerably.  The east Africans have been measured as having running economies in the range of 180 to 190 ml/kg/km.  Zersenay Tadese was reported to be the most economical runner in history, using only 150 ml/kg/km.  This is so low that I'm actually skeptical about the value.  (For more on this, check out this post from 2007, and see later in this post)

Nevertheless, using three assumptions, we can create quite an interesting picture of what the sub-2 hour marathon runner will look like, at least in terms of his 'engine'.

The graph below is the first step towards bringing all three assumptions together.  It converts running economy into a VO2 (in ml/kg/min) at 2-hour marathon pace (± 2:50/km).

Obviously, this picture is only partly complete.  The next question to ask is whether an average VO2 of say 67 ml/kg/min for a marathon (at the running economy of 190 ml/kg/min on the graph) is reasonable or not?  Can an athlete sustain that intensity for the required 2 hours?  Obviously, this question is not answerable in theory, only through measurement, but we can get an idea of whether it is reasonable by asking what kind of maximal capacity is required for each of the above VO2 values to be reasonable.

The graph below attempts to establish this.  It estimates the VO2max of the runner for two conditions:  One is that the athlete is running at 80% of maximum intensity (shown in red) or 85% of maximum intensity (shown in green).

So, for a given running economy, you can now see what maximal capacity might be required, or vice-versa, given a VO2max, you can estimate the running economy required for two different conditions.

Two examples:  High economy vs lower economy

The white lines show 2 examples.  Example A is based on the measured economy of African athletes (including some Olympic medalists) who have a measured economy of around 190 ml/kg/min.  At 2-hour marathon pace, they use 67 ml/kg/min.  That athlete, running at 80% of maximum, must have a VO2 max of 84 ml/kg/min.  If they were able to sustain 85% (which I don't think is possible), they would have an estimated VO2max of 79 ml/kg/min.

Example B shows the European athletes plotted in the very first graph of this post.  Here, a running economy of 210 ml/kg/km requires a much higher maximal capacity; in this case, either 92 ml/kg/min (at 80%) or 87 ml/kg/min (at 85%).  The point is clearly that in order to run a sub-2 hour marathon, the athlete requires BOTH an exceptionally good economy, and a high maximal capacity.  I guess the third option is that they could get away with worse economy if they were able to sustain 90% of maximum for that length of time, but I don't see this as very likely (but not impossible).

The Zersenay Tadese example:  Something missing in the picture

So where does this leave us on the question of the sub-2 hour marathon?  On paper, or in theory, a two-hour marathon is possible because we have seen running economies of 180 to 190ml/kg/km, and we also see runners with VO2max values of 80 ml/kg/min.  According to the graph, a runner with these "characteristics" can run the 2-hour marathon.  However, I've yet to see the two together, with the exception of  Zersenay Tadese, with his measured economy of 150 ml/kg/min and VO2max of 83 ml/kg/min.  However, as I said earlier, there's something not quite right there...

Here's the problem:  With that kind of economy, Tadese would be able to run at a speed of 2:50/km while using only 53 ml/kg/min.  Think about that for a moment:  he is running at only 64% of his maximal capacity, at 2-hour marathon pace.  He would be jogging to the world record if that was true.

Even his 10km pace of ± 2:40/km represents an underperformance, because at that pace, he would only be using 56 ml/kg/min, or 68% of his maximum.  We know that elite athletes run at at least 90% of maximum for 10km, which means Tadese should be sustaining a VO2 of 75 ml/kg/min, which, given his economy, predicts a 10 km time of just outside 20 minutes!

Clearly, something is wrong with that picture.  I actually emailed Carl Foster about this a while back, to ask about it, and he graciously replied, but then my computer got stolen, along with that email.  So Carl, if you are reading this, feel free to chime in!  I seem to recall that it had something to do with the timing of measurements - Tadese's VO2max and running economy were not measured at the same time, and therefore using them together created a problem.  And this is crucial - when we make this kind of estimation, we're assuming that VO2max and economy are measured together.  And if they are, then the more economical a runner, the lower their VO2max is likely to be.

The VO2max-economy relationship

For this reason, the combination of high VO2max and exceptional running economy is likely to be very rare.  So, let's get back to that graph above - does the athlete shown by "Example A" exist?  Is there an athlete with such exception economy AND such a high VO2max?  Or is the athlete with that economy likely to have a VO2 max closer to 70 ml/kg/min?

That is a question I don't have the answer to.  What is clear though is that even now, the current world record represents physiology that is close to this theoretical picture presented above.  That is, the current record equates to a runner with an economy between 180 and 200 ml/kg/km and a VO2max between 75 and 85 ml/kg/min.  Both of these are reasonable assumptions, which would lead one to conclude that a sub-2 hour marathon is physiologically plausible.

However, as I emphasized in my previous post, it's not as simple as this.  First, there are other "limiting" factors - thermoregulation is one that has not been mentioned yet.  To run a sub-2 hour marathon requires significant heat loss to offset the heat production, and so the limit may well have little to do with oxygen use, and everything to do with the avoidance of hyperthermia.  This factor certainly narrows down the opportunities to break the world record, because only a cool day will suffice - Dubai, Berlin and Chicago have all produced days that are too warm in recent years.  As the 2-hour mark is neared, that becomes even more crucial, and that's a big reason why I don't think we'll see more than one, small incremental improvement every five or so years.

And then finally, I must stress that this 'pre-occupation' with VO2max and oxygen as the determinants of performance is only part of the picture.  Performance is the sum of far more physiology than just VO2max and economy, and that's why the best indication of whether that sub-2 hour performance will be possible is, in my opinion, to ask what the implications are for performance over other distances.  If the shorter distances don't improve, then the longer one is unlikely to, and you can go through this same exercise for 10km and 21km events and you realise that we're right on the limit of physiological performance.  Doping would shift that limit, yes, and perhaps training.  But I still don't see it happening within the next 20 years.

Perhaps I will be wrong...as always, your thoughts are welcome!

Ross

Pressure points and performance: Choking and panic

Choking, panicking and other responses to pressure

Cricket is not a sport that we've done a great deal of analysis of here on The Science of Sport.  The irony is that the very first post we ever did, way back in April 2007, was the day of Cricket World Cup Final, which is currently on again in India.  That post, and maybe a few more on the marketing of the sport, represent the sum total of our cricket coverage (incidentally, cricket may be played seriously by only half a dozen countries, but it has one of the biggest player and fan bases of any sport, thanks to its huge popularity in India.  So powerful is the Indian "force" behind the sport that I once heard that the second largest supporter base for cricket is in the USA...thanks to the all the Indian immigrants!  Also, driven by the huge Indian market and its commercial clout, it is one of the wealthier and highest paying sports, at least for those fortunate enough to cash in on the 20-over format of the game)

South Africa - 5 out of 5, did they "choke"?

Cricket also gives us our lead-in to today's post, thanks to (yet another) South African failure to advance further in the 2011 World Cup.  SA lost to New Zealand yesterday, bringing to five a run of "failures" in World Cups.

Those of you who follow the sport, and everyone in South Africa, will be well aware of South Africa's reputation as perennial chokers.  Ever since the 1992 World Cup in Australia, South Africa have amplified the importance of the World Cup (on that occasion, it was rain that denied SA a chance), and every time, have fallen despite great expectations.

Part of the problem is that good performances between World Cups allow South Africans to build expectation to the point that we cannot possibly be beaten by another team unless we ourselves blow it!  It is the "You can't beat us unless we beat ourselves" mentality.  And the result is that when we don't succeed (and by success, you must understand we mean "win the whole tournament"), the post-mortem invariably falls on our 'choking' under pressure, because the underlying philosophy is that choking is when you lose games you should win (which, as we'll see, is not necessarily true).

Some of these failures have been agonizing for fans, most notably the failures of 1999, where dropped catches and run-outs against Australia only re-affirmed a growing perception that our cricketers were guaranteed to buckle under pressure. 

"Choking" up in lights

The latest failure is bound to produce the same response.  Everyone will speculate wildly on what  happened in Bangladesh yesterday, and the "choker" tag will be up in lights here in SA.  I know from my involvement with the SA Sevens team that such speculation almost always bears little resemblance to the truth.  Knowing what is going on in a dressing room over 4 weeks of a tournament, and during 7 hours of a match is impossible, and wild speculation usually INCLUDES the truth without being it!

So rather than add to opinion, I thought it would be a good opportunity to look at what choking really is.  The word is used so often that it's almost guaranteed to be misunderstood.  Just yesterday, within minutes of the defeat to New Zealand, expert analysis said that we had "choked and panicked".  The truth is that these two phenomena, both attributable to pressure, are polar opposites.

So let's take a look at what choking is, and how it differs from other failures under pressure.

Choking vs panic

Here is a great piece by Malcolm Gladwell on the "Art of Failure".  Regardless of your thoughts of Gladwell, this is a good summary, full of insight and explanation.  And for those in South Africa in particular, it would pay to get to understand what you're about to read about over the next few days!

Here are some quotes from the piece:

"Choking" sounds like a vague and all-encompassing term, yet it describes a very specific kind of failure.  Under conditions of stress..the explicit system sometimes takes over. That's what it means to choke.  Panic, in this sense, is the opposite of choking. Choking is about thinking too much. Panic is about thinking too little. Choking is about loss of instinct. Panic is reversion to instinct. They may look the same, but they are worlds apart."

Sometimes the other team is just better (on the day)

So choking, a fascinating area of sports psychology and performance, is a very specific kind of failure, and to blame it for defeat (especially surprise defeat) is too convenient and easy to do.  It's an overused explanation, and while there is almost certainly an element of both choking and panic in the latest defeat, team sports in particular are too complex for blanket explanations like choking.

The same focus will be on New Zealand later this year, when they host the 2011 Rugby World Cup.  They too have been labeled as chokers because they are consistently the best team in the world, but have failed to win the knock-out games in the World Cup.  Have they choked every time?  Unlikely.  Sometimes, it's just that the other team are better on the day, better able to raise their game when it matters.

As for the real explanation for defeats like South Africa's yesterday, only those involved can say, and they must be honest and hard to do find them successfully.  If it was choking (and maybe it was, at least for some individuals on the team), then denying it doesn't help. 

But it also doesn't help to blanket blame choking for defeat.  The only exercise that is effective (again, this is in my experience from the SA Sevens setup) is that every single person must shoulder responsibility, ask themselves what they needed to do differently and then aim to address it.  Were the best decisions made? Was the team prepared optimally?  Were there problems for many months leading into the tournament that were glossed over deliberately, or ignored because it was inconvenient to confront them?  Difficult questions, but lessons learned in failure are often the best ones.  If you're prepared to learn them.

Ross

Limits to human performance: Lessons from men and women

World Record limits?  What the men's and women's records tell us

Yesterday, I did a post discussing some of the physiology of performance limits, looking at whether we are close to reaching a ceiling of human performance?  As mentioned, it has been a recurring theme since we began this site.

For today though, an interesting approach to the issue dawned on me.  The main argument in yesterday's post was that human performance is limited by maximal capacities in one or more physiological systems.  Perhaps the maximal capacity to use oxygen.  Perhaps the maximal capacity to lose heat, or to store energy, to supply ATP, and so forth.  The physiology thus sets the ceiling, and really, the question everyone is asking when they about performance limits boils down to how close you believe we are to the PHYSIOLOGICAL limits set by these various system's capacities.

Statistical methods reveal some interesting possibilities, and certainly add value.  For one such analysis, check out this post, which concludes that the marathon "limit" exists at 2:01:48.  Given my arguments yesterday, over what is required for a runner to break 2 hours, this doesn't seem too far off the mark, but then what's 1 minute in 120?

However, I'm more interested in whether it's possible to predict a physiological limit based on the physiological capacities, like we did for the Tour de France climbing power output earlier this year.

Comparison of men and women, and what it reveals

It occurred to me that an interesting way of looking at this might be to compare the men's and women's world records, for a simple reason - many of the women's records are "unphysiological".  I'll elaborate more below, but many of the current world records for women date back to an era when doping was the norm, and most have not been challenged in well over 20 years!

Take a look at the table below, which illustrates this for 14 selected athletics events (I chose the events partly randomly, but also to exclude new events like women's steeplechase and pole-vault, and events where specifications have cleared the record books, like javelin).

What you are looking at are the women's world records on the left, men's on the right.  For each, the darker shaded column is the percentage difference between the World Record and the Best Performance in the last 3 years, just to illustrate whether the current group are getting close to breaking that record (you may have to click on the table to enlarge, apologies)

Now, what does this tell us?  A few things:

Women's records - out of sight.  Hard luck for women athletes

First, considering that there are performance bonuses for breaking world records, it's not great to be a woman in athletics.  The average age of the 14 women's records I've looked at is 19 years, 5 months, compared to 10 years, 10 months for men's records (which is skewed a little by the field events). 

Of the 14 women's records, only 3 are "younger" than 10 years, and 9 are older than 20 years!  That is, more than half the women's world records have stood for as long as the athletes now trying to break them have lived!

On the men's side, it's a lot more "fluid" - five of the records were set in the last 3 years (indicated by a difference of 0% in the shaded column), and only the field event records are older than 20 years.  If you rely on prize-money and record bonuses to make a living, being a woman athlete will cost you - you have no chance!  (In fact, the IAAF should scrap the women's performances and turn the record books back to zero, but that's another debate...)

In terms of how close the athletes are getting to the records, the pattern is much the same.  In the last 3 years, women have come within 1% of the world record in only 4 events, and this includes the 5,000m, which was set in 2008.  It also includes the women's 800m event, which, as we've seen in the last 12 months, is shrouded in controversy, first with Jelimo and then Semenya.

On the men's side, it's far more "competitive".  As mentioned, five of the records were set since 2008, and with the exception of the field events, all the events have seen performances come within 2% of the world record.  I do realize that the current crop of women marathon runners, for example, is pretty weak, whereas we're in a golden era of sprinting on the men's side, so this "snapshot" is incomplete, but it makes the point.

And that point is that men are much, much closer to their world records than women are.

The doping effect - shifting the "physiological capacity"

Now, the reason for this is obvious to anyone who follows athletics.  The women's records all date back to the 1980s, and if you go down the list, you will see only tainted performances from a tainted era.

Take the 800m event for women, for example.  If you look at the top 20 performances of All-time in this event, you'll see that:

• 13 of them come from the 1980s
• 2 were set by women who have since been suspended for doping
• 3 come from the early 1990s, which is when EPO made its big impact on sport (as seen by the Tour de France)

So that leaves only two performances not tainted by (or suspected of) doping of some kind - Pamela Jelimo and Caster Semenya.  And a lot has been said about those...

A bar set by physiology plus drugs, and a natural performance limit that can't reach it

The point here is that women have not improved in 20 plus years, and the reason is because the bar has been set by a generation of women who had an unfair advantage as a result of doping.

So what does this have to do with the limits to performance?  Well, if the only thing driving constant improvements in times was the "carrot" of a target, then the women of 2010 would be much closer to those of 1980.  Much like Roger Bannister broke the 4-minute barrier and supposedly showed others that the "impossible" was achievable, the theory has been put forward that the "limit" to performance is psychological.

I'm not belittling the role of psychology and belief, I'm sure it's a significant part of it.  But what women's records show us is that if the physiology can be enhanced, through doping in this case, then it sets the bar at a level that is now seemingly unmatchable, despite better training methods, better equipment, better diet, more advanced performance analysis and the passage of 20 years!  Unless you believe that the woman of 2010 is simply an inferior athlete (in most events, not just one), you should recognize that the performance limit of a non-drug using athlete lies BELOW that of the current records.

My conclusion then, is that women's world records will not improve, because the physiological capacity of the undoped female lies BELOW that of the doped athlete.  And therefore, women are very close to their physiological limit!

By the same token, men must also be close to their physiological limit, because there is nothing to suggest that women will have approached it sooner than the men.  The only way the records will "leap" forward now is if a population of new individuals, whose physiology breaks the "capacity barrier" emerges, like the Africans might have done in the 1980s.

Failing this, I do suspect we are getting ever closer, and in case of women's athletics, the performance limit lies somewhere between what is currently produced, and the records set by doped women in the 1980s.

Ross

P.S.  I realise that in the last 3 years, a number of those performances I've used in the table could well be drug-assisted as well.  This makes the argument stronger, because if the current generation are doping, and still falling 2% or more short, then that "limit" is well and truly out of reach.  Hence, the natural physiological limit is very close indeed.