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Monday, July 26, 2010

Tour power output reflections

Looking back on leTour - the post collection

Thank you for visiting The Science of Sport. Over the past few weeks, we've followed and attempted to analyse the performances of the very best cyclists in the world, and at worst, it's created some great discussion and back-and-forth.  At best, it's shown that cycling may just be heading in the right direction in its fight against doping.

Earlier today, Greg Lemond mentioned our analysis in his blog at Cycling News under the title "data of optimism?" and I certainly share that sentiment.  So for those arriving "late", below are the links to the three analysis we've done on the power outputs, courtesy data provided by SRM and Training Peaks.

Post 1: Power outputs from the Alps and Pyrenees
Post 2: The Col du Tourmalet - the showdown at 6W/kg
Post 3: Resolving discrepancies in the Tourmalet numbers

I'd encourage you to also read the comments, where you have really improved the overall quality of the debate with your own calculations and questions.

One of the big talking points in all these analyses is the issue of whether a performance is proof of doping.  Of course, the answer is no.  There are too many assumptions in the calculation of physiological implications of a given performance for it to be "proof".  Also, things like tactics and weather and preceding stages affect a rider's ability to produce a given power output.  However, when looked at in context and when those assumptions are "controlled" in order to create a 'best-case scenario', the picture is still, I believe, telling, and that is what the above posts are about.  There comes a point at which the principle adds value.

Of particular interest given the debate before the Tour, is that not a single longer climb hit the power outputs that we've become accustomed to seeing in 90s and 2000s.  Nor have they hit what we debated pre-Tour as the "suspect" power values of greater than 6.2, 6.3, 6.4 W/kg.

And while the 6.2 W/kg number got a lot of people riled, I really think it's telling that the very best climbers, with the highest level of motivation (on the Tourmalet) failed to hit those power outputs.  Re that number - in a debate about "unrealistic performances", you have to commit to a value, even if only to illustrate a point.  It does not mean this number separates the world into light and dark.

Even Contador and Schleck on the Tourmalet, in what was an absolute 'limit' performance, just touched 6W/kg as an average, and appear to have dropped right down towards the end of the climb (see post 3 above).  To me, this largely validates the physiological principle that says that for every performance, there is a physiological 'cost' and at some point, the 'cost' becomes an indication of doping.  In the words of Lemond, the performance becomes "believable".

There is no dividing line in the sand, no specific point at which you can say "got you".  A rider at 6 W/kg may be doping, and one at 6.2W/kg (depending on the situation) may not, but there is a theory underpinning it and the change in this year's Tour is a positive sign, leading to the hypothesis made in those posts and by Lemond.

It's been a super Tour, with great individual performances on stages, and the confirmation of a rivalry between Contador and Schleck that will hopefully put cycling in the news for the right reasons.  And hopefully, it's also produced a step in the right direction for the sport.  Bring on 2011, hopefully a mountain time-trial, and another super-tight race!


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Saturday, July 24, 2010

Power output on the Tourmalet - resolving discrepancies

Ferrari: "6.42 W/kg".  Everyone else: "Less than 6 W/kg".  Who is right?

Thanks everyone for the great discussion in response to the post yesterday looking at the climbing power output on the Col du Tourmalet.  As if often the case, your responses make the comments section to the post is better than the post, so if you have to time, you might consider reading it here!

However, a short post today, because something came across our twitter account yesterday and today mentioning that Dr Michele Ferrari has estimated the power output on the climb and his values contract those presented here yesterday.  I was going to post this in the comments section only, but I felt it worth putting out, since the disagreement is so large, and from such an 'infamous' source, that it demands attention.

From the site 53 x 12.com, Ferrari writes the following:
"Col du Tourmalet, in the last 9 km they climbed at 1780m/h, equal to 6.42 w/kg."
You'll recall that we said yesterday that:
"My overall estimation is that they took 49:08 to climb what I believe to be the final 17.6km at a gradient of 7.6%.  This gives a VAM of 1,633 m/hour, and a relative power output of 5.9 W/kg."
Even over the final 9.3km, after Andy Schleck attacked, we estimate a power output that is even lower than this.  We wrote:
Horner's power output over the final 4km will be very similar to that of Contador and Schleck, because of the constant time-gap between them.  There is some error thanks to drafting, wind and so forth, but we're talking small differences.  From the graph, Horner rode the final 4km at about 350W, and so Contador and Schleck finished the climb in this range of between 350W and 360W - 5.5W/kg to 5.7W/kg
So 6.4W/kg vs 5.9 W/kg?  Ferrari's numbers demand scrutiny, because they're so different.

Look at the SRM for the real values

And to find an answer, let's take the guesswork out of this and look at the SRM data - this way, we don't have to assume the length, the vertical gain in height, or the gradient of the climb.

So, for Chris Horner over the final 9.3 km (since this is what Ferrari claims is 6.42 W/kg (graph can be seen in yesterday's post):

Distance = 9.3 km
Gain in height = 736 m
Gradient = 7.91%
Time taken = 28:36
VAM = 1544 m/hour
Estimated power output = 5.53 W/kg

Of interest here is that the SRM gives Horner's power output over this interval as 348 W, or 5.4W/kg.  The VAM thus overestimates the power on this climb, and this is telling (bear in mind that if you have a following wind, you'll overestimate, whereas a headwind will produce an underestimate when using VAM - this is one of its 'flaws', and the reason why the SRM is the ultimate source of "truth", notwithstanding issues of calibration)

Now, let's look at Contador and Schleck over exactly the same 9.3km interval.  Remember that they all started this part of the climb together, with Schleck's attack creating the time gaps.

So, the stats are the same as above, with the exception of the time.  Horner concedes 1:46, and so therefore Schleck and Contador do the 9.3km in 26:50.

Now, VAM = 1646 m/hour
Climbing power output = 5.90 W/kg.

Not 6.42 W/kg.

The only way to explain this discrepancy is if the climb has been mapped differently, so that Ferrari's gradient and the vertical change in height over the final 9km are completely different.  Which is reality?  You have to believe the SRM.  Also, given that Horner is riding at 5.4W/kg, is it feasible that he "only" concedes 1:46 to guys supposedly riding a full 1 W/kg faster?  No, it's not, and so Contador and Schleck cannot have been at that power output.  And therefore, all Ferrari's assumptions and resultant calculations are doubtful.

The tactical battle - two ways to explain the racing

One final point about what Ferrari writes in that piece:
"the heat influenced the development of the TdF 2010, making the riding all the more demanding and hard, forcing the riders to measure out energies carefully, growing thinner and thinner every passing stage...None among the favorites dared to attack far from the finish, especially on the mountains, just as no team was really capable to make the race hard and selective in the first phases of the stages. "
Ferrari's observation can just as easily be explained by a reduction in the ability of riders to recover from one maximal effort to the next.  We know that doping improves this ability enormously - it improves the ability to sustain high power outputs and relative intensities for longer, and it enables repeat bouts at higher intensities.

Therefore, some of the hypotheses around a "cleaner" Tour would be that:
  • The same rider will not attack every day.  The "cost" of attack prevents this.
  • A single team with the identical cast of characters will not be able to dictate the tempo on the entire climb every day, and their ability to ride up more than 50% of the climb will be reduced (remember the days of three or four men from one team reaching halfway up a climb?)
  • When attacks are made, they have to be delayed, because the physiological/energy cost of attacking early and then sustaining 6 W/kg or higher for 40 minutes is excessive
  • The attacks themselves will be 'muted', at a lower power output.
I would argue that all three have happened, and not just in this Tour, but in the last two or three years, and in other 3-week races like this year's Giro.  It's not only the 5% to 10% reduction in power that is telling, it's the way races have evolved.  Look at Andy Schleck on the final climb - his hand was forced by the race situation - he had to attack early (9km to go is still later than some attacks back in the 90s and 2000s), and for his efforts, he and Contador paid so much that the chase group held them over the final 5km.  Their maximum effort was not sustainable.  And that's expected of physiology.  Doping, on the other hand, would allow it.

So the point is that Ferrari has blamed the heat, but there is another possibility, which must be acknowledged.  And sure, it's been hot.  I would argue that France in summer is always hot, and some basic thermophysiology is that heat is far less an issue on the bike than in running.  It's important, yes, but the thermal load produced by a temperature that is say 1 to 2 degrees higher than normal is not sufficient to produce these changes. 

I believe the more likely explanation is linked to what we (and NY Times, New Scientist and even Jonathan Vaughters) have pointed out, that performance suppression indicates a cleaner Tour.  Ferrari may have a different take, but then he did once suggest EPO was as dangerous as orange juice...

Enjoy the time-trial later!


Friday, July 23, 2010

Power from the Tourmalet - 6W/kg anyone?

6W/kg?  Barely.  Power output data from the Col du Tourmalet

Yesterday saw the big showdown of the Tour on its final climb.  Two great climbers in Alberto Contador and Andy Schleck rode man-on-man up one of the most famed climbs of cycling, in thick mist, in a battle that many felt would decide the yellow-jersey.  In the end, it won't, with a time-trial to go and two riders who were inseparable on the climbs.  But it was an epic day, and produced some epic performance.

So, to continue our analysis of the power outputs in the Tour, here are some insights, gleaned from Chris Horner, Chris Anke Sorensen and some self-timing of the climb (once again, power output files courtesy SRM and Training peaks)

The Tourmalet dissected.  First, some estimates...

To wet the appetite, some interesting estimates of power output emerged yesterday.  First, for a really methodical, and I believe quite accurate method of ESTIMATING the power outputs, check out Cozybeehive, where Ron has analysed the climb segment by segment.

This method of estimating the power output relies on using the rate of vertical ascension, or VAM, which can be calculated if you know the distance and the gradient of the climb.  And herein lies a problem - there are many discrepancies in how these climbs are 'mapped', and this affects the value you calculate.  Also, wind, drafting and changes in the grade also affect the final estimated power output.  There's been some pretty strong criticism of it, but so far, comparing the estimates to the actual SRM data has produced quite similar values, rarely different by more than 0.2W/kg.

On the note of distance, yesterday, the 18.6km to go banner for the start of the climb was almost certainly in the wrong place.  It took the peloton a full 4:42 to ride from the 20km banner to the 18.6km banner (speed of 18km/h), and that was before the climb.  Once on the climb, the first 3.6km took six minutes, a speed of 36km/h.  In otherwords, if you believe the banners, then you believe that the speed doubled once the climb began.  I don't, and so my conclusion is that the banner for the start of the climb was late by about a kilometer (this is further seen in the on-screen TV distances, which aren't always accurate, but they said 17.6km to go - I believe this).

So anyway, the point is that what you calculate varies quite a bit as a result of this.

Ron has estimated that the power of Schleck and Contador over the final 8km was 6.0 W/kg.  I think this is close, but likely a small overestimate, because of drafting effects.

My overall estimation is that they took 49:08 to climb what I believe to be the final 17.6km at a gradient of 7.6%.  This gives a VAM of 1,633 m/hour, and a relative power output of 5.9 W/kg.

These are of course estimates, not measurements, and if we want answers, then we need measurement.  And for that, we look to Sorensen and Horner...

SRM data from the climb

The graph below shows Chris Anke Sorensen's power from the start of the final climb.  If you recall, Sorensen set the climb up with an incredibly hard pull over the first 15 or so minutes.

So a massive pull - 415 W or 6.6W/kg, for 11:12, before Sorensen's day was up, and he dropped down to closer to 310W for the rest of the climb (also, note that the speed ranged between 20 and 25km/h, not 36km/h, which further suggests that the climb was marked incorrectly for TV purposes). 

Once done, Sorensen settled down to complete the climb in just outside an hour, for an overall average power output of 330 W (5.2W/kg)

Chris Horner - a barometer for the yellow jersey

Even more interesting is Chris Horner, who had a tremendous day, climbing with the very best in the world.  He was part of the chase group, dropped by Schleck and Contador, but who provide for a really useful barometer, because:
  1. The eventual time gaps were relatively small - 1:45 in 50 minutes - which means that while we can't know the power output of the leaders, but it's not too much of a stretch to infer, and 
  2. The gap between Horner and the leaders remained relatively constant over the final 5 km of the climb.  When Schleck attacked, the time gap grew relatively quickly to one minute, but then it edged up to 1:30, before actually staying in the range of 1:35 from 4km to go until the finish line.  Therefore, it's useful because Horner's power output in the final 5km will be very similar to what was produced at the front of the race.
So, here is Horner's graph:

SRM have divided the climb in half, with the separation conveniently co-inciding with Andy Schleck's attack.  Here's a breakdown:
  • Average power output for the first half of the climb - 377 W, at 5.9W/kg
  • Note the first portion of the climb, which co-incides with Sorensen's pull on the front, which we saw previously produced 6.6W/kg.  You'll see that Horner rode in the range of 390 to 400W over this period, or ± 6.3W/kg.  Horner's mass is 64kg, compared to Sorensen at 63kg, so the values are comparable.  The reason it's lower is the slight benefit of shelter in the group, whereas Sorensen was at the front of the race
  • After the attack came, Horner completed the climb at 348 W (5.4W/kg). 
  • Note once again, that Horner's power output over the final 4km will be very similar to that of Contador and Schleck, because of the constant time-gap between them.  There is some error thanks to drafting, wind and so forth, but we're talking small differences.  From the graph, Horner rode the final 4km at about 350W, and so Contador and Schleck finished the climb in this range of between 350W and 360W - 5.5W/kg to 5.7W/kg
  • Horner's overall average power output on the climb was 360 W, or 5.6W/kg.  Interestingly, if you use the VAM method for Horner, you calculate a power output of 5.7 W/kg.  Therefore, I am quite confident in saying that Contador and Schleck probably averaged 5.9W/kg over the entire climb.
So, a fascinating graph and insight into the Tour's big day.  But what does it all mean?

The physiological implications of the climb

Before the Tour began, there was a great deal of debate about what the performances tell about physiology.  I suggested that the power outputs of the 90s and 2000s, where these climbs were frequently done at 6.2, 6.3 and even 6.7W/kg, were a sign of doping.  You may recall the notion, developed by Dr Ferrari and communicated by Armstrong in his book, that they aimed for 6.7W/kg as a threshold climbing output.

Nobody has managed to achieve even 6.2W/kg for any length of time in this Tour de France, let alone 6.7W/kg.  Unless I am missing something.  6.6W/kg for 11 minutes, yes, but that rider then dropped to 5W/kg for the rest.  In days gone by, that was the tempo the whole way (Incidentally, you can play around with this and work out how far ahead a guy would be if he did ride at 6.7W/kg - I estimate close to 3:00 on the climb.  Contador and Schleck, dropped by 3 minutes....?)

And the top two climbers yesterday arguably rode at around 6.0 to 6.2W/kg for the first half of the climb, but their power output dropped off in the second half (which we know, because the time gaps ceased to grow over someone who was producing 5.5W/kg).

What is the physiology of riding at 6W/kg?  If a cyclist has an efficiency of 24%, then the VO2 at 6W/kg is about 71 ml/kg/min.  If this represents 85% of a maximum, then a VO2max of 83 ml/kg/min is estimated. If the efficiency is 23% (measured by Coyle for Armstrong in 1999), incidentally, then the VO2 is 74ml/kg/min and the estimated max would be 87 ml/kg/min.  Neither jumps out as not-seen-before-physiology.  But, if you go up to 6.2W or 6.3W/kg, then it starts to become, well, questionable.

Horner, incidentally, riding at 5.6 W/kg, would have an estimated VO2 of 66 ml/kg/min.


All told, then, I interpret the figures to be a good indication of the state of the sport. Whether you want to:
  • Base this on the physiology (which is only part of it, but I believe an important part), or 
  • Compare the climbing times (most of which are 5 to 10% slower than before), or 
  • Compare the estimates of power output this year to previous years (again, they're consistently 5 to 10% down), you arrive at the same point - it's a slower Tour.
Now, tactics are of course important.  Many of you have argued this, and of course you're correct.  Race situation dictates who attacks, when they attack and how they ride.  That's why you need many climbs, and not a single one, to reach a correct conclusion.

One Tour provides many climbs, and I think there's still huge value in this year's numbers.  However, because it's still a small number, this is a hypothesis, not a finding - what would be fantastic would be to track these stats over the next ten years, and compare the 90s to the 2000s to the 2010s.  And also, to look at averages for top 10, top 50, top 100, to get an idea of depth.

Yesterday, on the Tourmalet, there were tactics - ride as hard as possible.  6.6W/kg from the bottom, followed by an attack, and I don't see any signs of 'hedging' of physiology on the day.  It was as hard as was possible at that stage in the Tour, and I would continue, then, to hypothesize that the more stringent doping controls, the biopassport and the scrutiny on the sport have helped bring it down.

Call it "physiologically believable" (which many don't like, but I use it with its obvious intention), or call it signs of change, I do believe that the Tour is slower, and that the days of 6.3W/kg for 40 minutes are now the stuff of highlights and commemorative DVDs.

A massive time-trial to come, where the Tour will be decided!

Enjoy it!

Wednesday, July 21, 2010

Power outputs from the Tour de France

Power outputs from the Tour de France

It's been a while since we last posted - the pressures of family and work, and actually watching the Tour are to blame!  We've missed so much in the last few weeks - Caster Semenya is running again, though reading anything into her performances right now is guesswork at best.  Two possibilities remain, with no way to gauge them until later in the season.  Then in France, Christophe Lemaitre ran 9.98s for 100m to enter the history books.  Big deal, right?  These days, 9.98s doesn't even guarantee a medal at a major race (in fact, it's almost certain that you won't medal).  But the result is significant, because Lemaitre is white...the first Caucasian man to break 10 seconds for 100m.

This opens up the debate about genetics in sport.  It's a debate that either focuses on the endurance gene (what makes Kenyans and Ethiopians so dominant?) or on the speed gene (West Africans and Jamaica and the USA).  It's a debate that is heated, because it has anthropological, racial, cultural and social implications.  It's also a debate for another time, but worth just bringing to your attention, because Lemaitre's performance is significant, historically and scientifically.  Here's a good article that gives it some perspective

But, the point of today's post is the Tour de France, so let's change gears and look at some power data, as we enter the Tour's decisive next 3 days.

Power data from the Tour - two sources worth browsing

First, for more power data for the number-fiends among you, there are two sites worth browsing:
  1. Training Peaks - power output data from Saxo Bank riders (not Andy Schleck, unfortunately), with analysis
  2. SRM - similar data, but for different teams, including Saxo and Radioshack, and a different take on some of the numbers.
I've used the graphs from the SRM site below, only because they're easier to follow.  Both are great, and they explain the pattern of the race better than I possibly could.  So when you're done here, if you have time, it's worth visiting them!

The Pyrenees - considerably below 6W/kg

Chris Horner:  A top 15 rider (currently lying 14th), Horner has finished most of the mountain stages in a second or third batch of riders that include Ivan Basso, Andreas Kloden and within touch of Robert Gesink.  Always in the top 20, he gives a good indication of what is happening at the very front of the race.  Unfortunately, we don't get this kind of data for Contador, Schleck, Menchov or Sanchez, to really see what is happening during the attacks in the final kilometers, but nevertheless, Horner's data is interesting, as you will see.

On the short climb (3km) up to Mende in Stage 12, Horner finished 31 seconds behind Contador, having begun the climb with him. Horner's average power output for 10 minutes of climbing was 6.6 W/kg (422W). Nothing wrong with that, it's a really short effort at the end of what wasn't a super-grueling day like those that followed in the Pyrenees.

For context, consider Horner on Ax-3-Domaines during Stage 14.  This finishing  climb took him just under 24 minutes, and his power output was 5.8 W/kg (370W, 12% lower than for the 10-min climb). He conceded about 90 seconds to Schleck and Contador.

Then even longer was the climb of the Port de Pailheres, which he rode in 48:37 (as did all the main protagonists, give or take a second or two), and that was done at 5.4W/kg (344W, a further 7% lower). Of course, it's not a finishing climb, so the hammer isn't down, but it does reflect what the peloton is doing.

Also, Horner's data from the Port de Bales are interesting. He finished this day with Basso, conceding approx. 3 minutes to Contador's group by the finish (not 100% sure of the gap at the summit, but imagine it would be 3 min ± 20 seconds). This climb took 49:30, and was done at an average of 342W/kg (5.3W/kg - about the same as the Port de Pailheres of similar duration).

The power required to drop leading riders

And then finally, it's interesting to look at the data of Chris Anke Sorensen (apologies for all the graphs).  Sorensen has been the last Saxo man to peel off before Andy Schleck and the GC riders duke it out, and so his numbers are fascinating because they show you the effort that has produced a thinning out of the peloton.  For example, on the Port de Bales during Stage 15, Sorensen rode at the front of the peloton and was responsible for dropping all but 15 riders.

Then he went off, and the attacks began.  What I have to point out is that once he goes off, the overall pace actually slows DOWN, it doesn't get faster.  This is because the initial attacks are neutralized and then followed by a regrouping.  On the Port de Bales climb, it was Andy Schleck who attacked, and an elite group of 5 formed.  But soon, that group had swelled to about 15 again, with Lance Armstrong almost rejoining it.  So the point is, the power output by Sorensen, in my opinion, reflects the highest SUSTAINED power output on the climb - the attacks go higher, but it's more stochastic, with periods down below 5W/kg.

So let's look at Sorensen on the Port de Bales.  He rode at the front of the peloton for 21:34 and produced an average power output of 385 W, or 6.1W/kg.  As mentioned, this thinned the group to 15 riders.  The smaller Schleck, riding behind him, would produce less than this, and is sheltered from the wind (the speed here is around 18km/h, so it's not insignificant) - perhaps 5.7W to 6.0W/kg, and that's a good indication of the power produced by those top contenders.


So what does all this mean?  First, it's really interesting (I hope) to compare these numbers to what you may produce if you are a keen cyclist.  I wish that more data like this was made available, I think it would enhance the package of cycling.

But, to continue a debate we've been having recently, these numbers reflect, in my opinion, an overall lowering of the performance level in the Tour compared to the last 2 decades.  And this is a positive sign that doping control measures are having an effect.  Even yesterday on the Col du Tormalet, the climbing time was 56:30 for the Yellow Jersey, compared to that huge day in 2003, when Armstrong and Ullrich did it in 44:30.  And yes, the race situation was different, but 12 minutes?  That's too big to be accounted for by strategy alone, even weather conditions (yesterday may well have been more favourable anyway).

Tactics play a role, but are themselves a sign

Similarly, on Ax-3-Domaines, Contador and Schleck were racing in a tactical battle that saw them almost come to a standstill on the road for a short while.  It was fast-slow, stochastic riding, and they would surely have gone 30 to 60 seconds faster without this.  But those tactics may themselves be necessitated, because the days of riding at 95% for 25 minutes on the final climb of a tough day belong in the 1990s and 2000s. 37 minute efforts at 6.4W/kg, including attacks?  You may have to watch the reruns to see that...

I look at numbers like 5.4W/kg for the peloton on the penultimate climb, and around 6.0W/kg on the final climb as a good indication that something is different, and in a good way.  Hey, they may even reach the much-maligned 6.2W/kg for a climb like Ax-3-Domaines, but the contention (mine and Sassi's, and probably other's) that it's not physiological to ride at around 6.2W/kg or higher for 40 minutes seems, at least so far, unchallenged in the "real world".  Ax-3-Domaines was done at 5.8W/kg by a rider 90 seconds down.  It would be pretty easy to make the calculations for Contador and Schleck, using the SRM data to validate the accuracy of the assumptions you make.  Feel free to go for it!

I, on the other hand, had better get some student exam marking done!

Enjoy the showdown on the Tourmalet tomorrow!


Monday, July 12, 2010

More feedback on football and cycling

World Cup Final analysis and more on cycling performance limits

I have too little energy (and time) for a proper, in-depth post, but as promised, analysis from last night's World Cup final is now done, courtesy Zonal Marking.

It's another great analysis, from a site that has really increased my enjoyment of the tournament, and you can read it here.  I wish that all sports would embrace this kind of analysis - can you imagine if the "experts" on television produced such clear and insightful thinking for rugby, football, tennis, cycling, and even athletics?

One or two thoughts on the analysis - I agree that Holland set out with spoiling tactics and wanted to physically disrupt Spain's creativity.  Early on in the game, the flurry of fouls predicted that at some point, a red would be issued. It might well have been in the first half, with two horror challenges getting lenient treatment, but it could easily have been 11 against 10 as early as 35 minutes.  Spain were involved too, and it's always an interesting dynamic how the entire game degenerates into petulance and over-aggression when one team starts out with that approach.  That certainly seemed the case last night. 

There has been much criticism of referee Howard Webb, but I feel that his performance was more a reflection of the players' performances rather than a controlling one.  He could easily have shown red on two or three occasions before 90 minutes was played.  And also, I have to point out, given that we've had so much debate on this site about the cheating and fouling in football - if that was Uruguay or Italy or another South American team, and not Holland, there'd have been an uproar, widespread condemnation for 'typical dirty play'.  Spain weren't blameless, no, but for Holland last night, it was a poor showing.

The last 20 minutes of the match and extra-time finally told.  Space appeared (which it always does - as we saw with our post on fatigue, players lose about 8 to 10% of their speed by the end, making it much more difficult to press and close space).  Spain looked more likely to construct a goal, Holland remained dangerous on the break, but in the end, Spain wrestled control away and for the last 50 minutes of the match, were completely in control.  All they lacked was incision and composure in front of goal.  David Villa was poor for a second game - he is not suited to that lone central striker role and looked far more threatening when playing wide and coming in.  If Spain had him out there and an in-form Torres, they'd have scored twice as many goals this tournament.

Lastly, as Zonal Marking points out, Spain have won the European Championships and the World Cup, playing seven knock-out matches and not conceding a single goal in those games.  Attack wins matches, but defence wins tournaments.

Cycling - more on doping and performance limits

We've had some lively debate just recently regarding whether performances, and the physiological basis they require, can be used to flag (not prove, let me emphasize) doping.

And today, the New York Times ran a piece looking at much the same thing.  You can read it here.

This is another example of what I consider very interesting, well applied science to the sport.  I agree with Aldo Sassi around his limit to performance, I do agree that there is a grey area, and I believe that this grey area exists below 6.2 W/kg.  Others disagree, I'm sure.  Some have said this is "science at its worst".  I couldn't disagree more strongly - it's science at its best, being applied in the pursuit of an answer.  The very fact that it is debated makes it worthy of discussion, since there is no answer but a compelling reason to question.

People will always decide, of course, based on what they want to believe.  We will see what happens in this year's Tour, but if the top 5 of this year's Tour are climbing at the same power outputs as the Top 30 from Tours in the early part of the century, then either cycling has a vacuum of talent, or we're seeing an indictment of the 2000s, and the cleaning up of the sport now.  And physiological demands of the sport will highlight that change.


It's Spain!

It's Spain!  World Champions 2010

Spain are the World Champions.  A tense, highly dramatic final in Johannesburg went all the way to the wire, through 90 minutes and very nearly through extra-time, but an Andreas Iniesta goal in the 116th minute gave Spain a well deserved win.   46 fouls (compared to only 16 in the equally competitive semi-final) and 13 different players booked (including one twice - John Heitinga of Holland) was an indication of the flow of the match, and in truth, there might have been red cards sooner.  And there was plenty of screaming at the referee as football's ugly side came out for a last SA appearance.

But on the whole, an enthralling match, despite the lack of goals.  Spain controlled possession, as might be expected, but both teams created excellent chances, one-on-one opportunities with the keeper, headers from close range and other great opportunities.  An interesting stat is that before this game, Spain had actually created more shots on goal than Holland (82 v 67), but their accuracy of shooting and conversion was much lower (7 v 12), suggesting a lack of penetration, and probably also the approach adopted by their opposition.  For a brilliant piece on this, check out this article by Sports Illustrated before the final.

However, back to the final, and the game seem destined for penalties until Iniesta, a stand-out player, sealed the win for Spain.

I defer to Zonal Marking for full analysis of the tactical battle, in due course.

Le Tour - a timely antidote to withdrawal

Next up, the Tour.  Today was also a big day in the Tour.  Lance Armstrong's GC challenge ended with an 11:48 time-loss on the final two climbs, after a crash at the bottom of the penultimate Category 1.  At the front, Andy Schleck won the stage, and managed to throw down an attack that Alberto Contador couldn't match - a first for perhaps two years.  A group of 11 was together at the end, suggesting that this was not the big day in the Tour, with the GC riders happy to ride strongly up the final climb without aggressive attacking.  Until Schleck 1km from the finish, that is.  It sets the Tour up as a great battle - Cadel Evans holds yellow, Schleck is 20 seconds back, Contador a further 41 down.

But it has a wide open feel to it.  Rest day tomorrow and then we're back in the monster Alps.  Thankfully, after this football festival, I need something to help with withdrawal!

Well done Spain, deserved World Champions!


Friday, July 09, 2010

The World Cup Final and leTour hits the Alps

A preview of a massive sporting weekend

62 games down, 2 to go.  And the final game, on Sunday night, will see a first-time world champion crowned when either the Spanish or Dutch claim the World Cup.

Gladiators in a Colosseum

It will be an incredible match at an incredible venue.  I was fortunate enough to watch World Cup matches at Loftus in Pretoria (39,000 attendance that night), in Cape Town's Green Point stadium (about 65,000 at each of the matches I watched) and a match at Soccer City between Brazil and the Ivory Coast, where 85,000 people attended (picture right).  Cape Town is an amazing setting, certainly the most beautiful location for a stadium in the world, but Soccer City, well, it's just a breath-taking, hair-on-the-back-of-the-neck-standing-up stadium for its size and atmosphere.  If the Cape Town stadium hosts football matches, then Soccer City hosts gladiators in conquests, and anyone fortunate enough to be there on Sunday night is in for an unforgettable experience.

The match-up between Spain and the Netherlands brings together two of the world's pedigreed footballing sides, remarkable for the fact that neither has won a World Cup.  The Dutch have featured in two finals, during the "total football" days of Rinus Michels and Johan Cruyff in 1974 and 1978.  On those occasions, they fell short at the final hurdle. Spain meanwhile, had never even reached a semi-final, despite being home to two of the great club sides in world football (Barcelona and Madrid), and despite producing some of its great players. 

The Spanish have been solid and compact this year - they've only conceded two goals, the fewest in the competition, but have been less than incisive and spectacular at the other end of the pitch.  David Villa is their big threat, with 5 of their 7 goals to date.  However, as they have shown before, they have the ability to score from anywhere and a player in Fernando Torres who is only a second away from a return to goal-scoring form.  He may come off the bench, but it may be with impact.  If Vicente del Bosque chooses to stick with Pedro in his starting 11, it gives Spain more width and incision.  And with seven of the starting line-up likely to come from Barcelona, they have understanding too. 

The Dutch have been professional and clinical, and with on-form players everywhere, as well as two match-winners in Robben and Sneijder, they will be difficult to contain.  As has been the case all tournament, a lot will depend on who controls the midfield, which is a function of players, space and press.  Spain's pressing against Germany was brilliant, and rendered the German midfield largely anonymous by denying them space and time on the ball.  However, an interesting stat that I came across is that 47% of Holland's passes have been inside their own half, the lowest of the tournament, and a sign that they are happy to play deep and patiently.

It should make for an intriguing tactical contest, as well as a technical spectacle, with some of the finest technicians in the game on show in Xavi, Iniesta, Alonso, Robben and Sneijder.  The Spain v Germany semi-final had only 16 fouls in it, a clean, open match with none of the drama of some other matches, or the play-acting that has come to characterize football.  The Dutch have (in my opinion) been one of the worse offenders in this regard, and indeed Spain have also been accused of the same in the past, but I hope that the final produces the kind of attitude that both the semi-finals did, and we see a good clean contest (which makes it sound more like a boxing match, but anyway)

A link for the analysts among you

The technical analysis of the match is of course a fascinating area for me, and while I have more thoughts on how this match will unfold, I think it best to defer to what I think is the best site for football analysis that I've ever read.  In fact, I'd go so far as to say that this website is the best sports analysis site I have read, because it is accurate, technically detailed, but somehow retains simplicity at the same time, which is a rare combination.   I have friends who know little of the sport, but they are 'experts' in five minutes having read this.  The mark of great thinking is to take the complex and simplify it to make yourself look simple!  And this website does it brilliantly.   It's called Zonal Marking, and you can check it out here.

For an example of a brilliant post-game analysis, check out this post analyzing the German demolition of Argentina.  The comments are equally informative and high in quality.  And check in over the next day or two for his preview of the Spain v Holland final - the previews are accurate and they'll certainly enhance your appreciation of the match.

The altitude - Spain's familiarity may give a pacing advantage

The other factor that I do think may have a bearing is the altitude.  The only reason I point this out is because I noted today that Spain have played half of their six matches at altitude, whereas the Dutch have played at altitude only once.  That match was their 2-1 win over Denmark, and after the game, both teams really complained about the altitude.  The Dutch were quoted as saying that they struggled, both with breathing (dry mouth, shortness of breath) and the flight of the ball.

Of course, that match was three weeks ago, and they've had time to adapt, but I do think it is relevant that they've played five matches at sea-level since that, whereas Spain have played three at altitude over the same period.  Purely in terms of familiarity, this could become important.  I'm not sure where the Dutch have been based between games - their base was in Johannesburg, but teams travel to match venues up to 3 days before kick off, so it is possible that they've spent maybe 5 days out of 27 at altitude, compared to 20 for Spain. 

I posted earlier in the week that the altitude is certainly having an effect on the tempo of the matches, lowering total distance, high intensity distance and the number of sprints completed by each team, and I do feel that a crucial part of improving performance at altitude is learning how to pace the efforts.  And I believe Spain has an edge in this regard.

The crystal ball comes out

So for a bit of fun and because we're fans after all, I figure why not whip out the Science of Sport's crystal ball and throw out a prediction.  A tight game, as finals always are, will produce a goalless first half.  Spain will control possession, by pressing up on Holland, whereas Holland will be content to sit deep and rely on Kuyt and Robben to find space wide. 

So 0-0 at half-time, but Spain to score in the second half, with maybe 25 minutes to play.  Then Holland will throw players forward and be exposed in defence, and the final score will be 2-0 to Spain.  Torres to seal the win with a counter-attack goal at the 84 minute mark.  The Dutch will simply lack the sharpness at the end as a result of the altitude and Spain's relentless control of space and possession!  Also, I believe the experience counts for a great deal and given that Spain played in and won a 2008 Euro final with many of the same players, their familiarity will help them through.

And that's the crystal ball.  Don't worry, it's hardly ever correct, except for once in the London Marathon!  Whatever happens, let's hope for an open, positive and fair match, where the best team wins without the controversy and bad-taste of previous finals.  And please, no penalties!

The cycling hits a big rendezvous

As for the other massive sports event this weekend, the Tour de France hits the Alps tomorrow, and on Sunday, sees its first big mountain top finish in Morzine.  The stage profile is below:

With such a mountainous Tour still to come in the Pyrenees, this stage may well not produce the decisive moments in the Tour, but it is the first big rendezvous among the GC contenders.  The first week of the Tour produced plenty of nervous moments, eliminated two GC contenders and challenged all the others at various times, but the stage is set for the battle in the mountains.

Once the World Cup is finished, this becomes our big focus, so tune in for some thoughts next week!

Enjoy the World Cup final!


Thursday, July 08, 2010

Rudy Pevenage admits to Puerto involvement

"It was a normal thing to do."

Well, seeing as how it is Tour time, doping scandals seem to be part of the scenery in July.  This year is no different, first because of the Wall Street Journal's article "Blood Brothers" which ran on Saturday during the prologue, and now because Rudy Pevenage has admitted to helping Jan Ulrich dope with Dr. Efumiano Fuentes, he of Operacion Puerto infamy.

I know what many must be thinking. . .that perhaps the admissions and info provided by Floyd Landis has somehow created a critical mass and more admissions will follow.  That perhaps Ulrich himself will make good on his promise to one day "reveal what he did during his career."  It would be the best thing for the sport because finally the UCI and others will be forced to admit that if there is not a problem now in 2010, at least there was only a few short years ago.  But all I can say is let's not get our hopes up just yet, because one can never, ever, underestimate the power of omerta and the denial of the officials and many fans.  There is a mountain of admissions, positive tests, circumstantial, and physiological data, but in spite of all this evidence many still believe either that the sport was never that dirty, or "that was  then, this is now," meaning with the biological passport suddenly things have changed.

The normalization of doping

You can click back to Cyclingnews.com for the details, but perhaps most telling is Pevenage's quote in the title of this post---"It was a normal thing to do."  He admits that not once did he feel like he was doing anything wrong.  Mind you, this is exactly what many dopers repeat again and again, including Landis.  He has expressed no regret for doping, and instead he saw it only as the necessary next step to climb to the top of his profession.  When illicit activities like taking hormones and infusing blood, which most of us express huge inhibitions to, suddenly become the status quo, you know you have a problem.  This is the effect of a sport's "culture," and before we get beaten again with the science stick (!), let me reiterate again that to understand fully doping in sport, one must consider all the angles, even the "social science of sport." The physiology is indeed a large part of the doping, but there are always many other angles that contribute to the entire picture.

Instead of cyclists being inhibited and choosing not to dope, for those wishing to reach the pinnacle or for those wishing to merely survive, doping is an entirely acceptable option.  It is the normal thing to do.  And until cycling---and all sports, mind you---can change that culture and that mentality, doping will persist, sometimes in epidemic proportions, although any doping at all is unacceptable.  Michael Shermer's application of Game Theory to the doping situation best summarizes it.  Until the negative consequences of doping are larger than the positive consequences of doping, it will persist as a behaviour in sport, primarily because right now there is still little risk of being caught and the benefits in the form of larger salaries, more endorsement deals, and renewed contracts, far outweighr the risks of getting caught.  And even getting caught is not the end of the world---just look at Ivan Basso's and Alexandre Vinokourov's mostly trouble-free returns to cycling.

How responsible are the coaches?

On another note, this brings up a question that has been asked before regarding the complicity of coaches and/or managers.  Typically the athletes test positive and suffer the consequences while the support staff are rarely implicated.  This has changed in the past few years as some coaches in athletics have been banned from the sport.  Most recently, Jamaican and four-time Olympian Raymond Stewart has been banned for life for buying banned substances from a supplier for his athletes, and previously Trevor Graham and Remy Korchemny have been given "life sentences" from their sport.

But is should be noted that these individuals were banned because it was shown they had a role in physically securing the drugs. and the larger question is even if a coach cannot be proven to have a role in buying the drugs, yet a string of his or her athletes test positive. . .how complicit is the coach?  Can they be held accountable at all?  It is a very gray area, and perhaps difficult to argue as it means the coach must now take some responsibility for another individual's actions.  However one might argue that if this is the case, then perhaps it might serve to deter doping or also might encourage third-party drug testing by teams and coaches, thus adding an additional layer of scrutiny outside of the organizing bodies.

Vive le Tour

In the mean time, the tour this year has produced some great, if not controversial, racing.  Stage 3's finish on the Arenberg cobbles, while not a favorite of the riders, cracked the race open and produced dramatic results from Cancellara reclaiming the yellow jersey to Andy Schleck and Cadel Evans riding themselves back into contention before the first mountain stage on Saturday.  And speaking of the weekend, what's a sporting fan to do?  Between the Tour de France and the last two World Cup matches, I hope your Tivo is working!


Tuesday, July 06, 2010

Caster Semenya cleared? Is this finally the verdict?

Caster Semenya to return to competition: Reports from the IAAF

It is being reported that Caster Semenya, South Africa's 800m World Champion, will be given the all clear to return to the track.  Before getting carried away at the conclusion of what seemed a never-ending saga, let's remember that on no fewer than three occasions, the SA government have organized triumphant press conferences only to cancel them at the last minute to delay the announcement further.

However, on this occasion, a reputable source, the Telegraph, are reporting that the IAAF will make the announcement and not the SA government, which gives one more confidence that perhaps, this is the final decision.  The story from the Telegraph can be read here.

If it is indeed the case, then it will bring to an end 10 months of speculation, rumour, accusation, and denial.  We've tried to follow the story, from its beginning in August last year, and there is not too much more to be said about why it has taken this long, and what may have happened over the last 10 months.

In the report by the Telegraph, I feel the most telling paragraph is this one:
"Her coach, Michael Seme, has admitted that she has not been training at 100 per cent due to the uncertainty over her future, while it is also believed that she has been undergoing medical treatment for an inter-sex condition."
That alleged treatment, which I also believe to have taken place, holds the key to why this has taken so long.  The IAAF, you'll recall us discussing before, find themselves in a difficult situation of having to avoid discrimination against ANY athlete (not only Semenya, as the SA sports fraternity wanted to believe).  So their obligation was to ensure equality of competition without discrimination.  And there are a range of issues about this, from social to cultural, even religious, all of which have been had in various forms over the last 10 months.

However, from a sporting point of view (and my bias here is sporting performance), the requirement is to manage the case to ensure that all athletes receive fair competition.  Therefore, treatment, to lower the testosterone levels and attempt to reduce any advantage as a result of high testosterone, would have had to take place, and that may be the reason this has taken so long to resolve.

Legal Tug of War

Because make no mistake, actually diagnosing the condition is a relatively simple procedure.  Knowing what to do about it, not as simple.  So over the last 8 or 9 months, the issue has probably been how to treat (if at all) to ensure competition.  The legal teams on both sides would have had their requirements.  I've no doubt at all that the IAAF would have been pushing for surgical removal of testes, where Semenya's camp would probably have resisted this.  The IAAF will probably have pushed for surgery as a key requirement for Semenya to continue her career in athletics - I'm not sure of the legal issues around this, but that is likely to have been their desire.  Semenya's team may have argued against this as an infringement on her right to decide on her medical treatment, and also to compete without that surgery. 

The eventual compromise may have been medical/hormonal treatment, and the process of the treatment and monitoring the response to that treatment would take time to track.  Hence the delay.

Will the details of the process be announced?  Or does speculation continue?

Of course, this is all speculation, and hopefully, further announcements will clear it up.  Here again, we have another fierce debate - should more detail be disclosed, or does "medical confidentiality" dictate that no announcement is made?  I've felt since the beginning that once the first leak happened, it would be in Semenya's best interests announce as much detail as she could without compromising herself too much.  In fact, if I think about it, the more she discloses the better, even at the risk of giving away too much information.  Better to control the facts than allow them to be made up or to sow mistrust and suspicion that it was a 'technicality' that got her cleared.  Simply returning to competition with no announcement will create mistrust and another round of speculation as the rumour mill begins to spin.  On the other hand, one can appreciate Semenya's desire for privacy, but this will be interesting to follow. 

The impact of reduced testosterone on performance?

The other very interesting thing to observe is whether Semenya's performance levels will remain where they were.  This is what most athletics followers will now be looking at.  If it is true that her testosterone levels have been reduced, even chemically, then it will certainly have an impact on performance, mostly because of the effect it will have on her training adaptation.

Athletes use testosterone as a drug primarily because it enables a higher level of training performance and more rapid recovery post-training.  The combination of the two equals improved performance.  A removal of testosterone would impair both direct responses and recovery capacity, and I feel that the recovery is the more crucial of the two in the larger scheme of things.  The immediate effect of 'testosterone withdrawal', in an athletic sense, is to reduce the level of training the athlete can manage without either running into injury or overtraining.

Therefore, if Semenya is to return, what is more telling will be how she adjusts her training, and not necessarily her race performances, because these are the result of her training performances, and whether her coach is able to manage an athlete who may very well be going through substantial physiological changes.  That will be the first big hurdle to overcome.

The East Germans had previously calculated that a doping programme (primarily with anabolic hormones, of which testosterone is one) could improve performance in shot put by 17% in one season!  That is not an acute effect, mind you.  Rather, it is the cumulative effect of the training that is done while doping and benefiting from higher testosterone levels.  The east Germans also worked out that doping was worth between 5 and 10 seconds in an 800m event for women.  In fact, for those who are interested in this research, you can read that post, based on the secret documents uncovered by Werner Franke, here.

Is the "loss of performance" when reducing anabolic hormone levels the same as the gain from increasing them?  Honestly, I don't know.  I don't think anyone does, and this case has no precedent.  So there are no answers.  Some of the physiological and anatomical changes induced by testosterone during puberty will never be reversed, others will.  How performance, the sum of all these factors, is affected, remains to be seen.

Of course, all of this is speculation, because we still don't know the details.  And so we're back again to the issue of whether anything will be said, other than that "she is clear to compete".

The next steps will be interesting.


Monday, July 05, 2010

Football analysis: Altitude and goal scoring

The effect of altitude on the 2010 World Cup

Amazing to think that we're now done with 60 out of 64 matches, and by this time next week, the World Cup will have left South Africa.  It's been a month-long celebration here in SA, and while the disruption to work and traffic and general life will be over, we're bracing ourselves for the mother of all hangovers down here!

Fortunately, the Tour de France will be into its second week, and so the withdrawal will be minimal, and here on The Science of Sport, we'll keep forging ahead with the next big thing!

Today, a look back at Round 1 at some really interesting statistics, first regarding the altitude and then the goal-scoring.

The effect of altitude on physiological performance

Before the tournament began, I did a series of posts on this issue.  This level of competition in a team sport like football rarely takes place at altitude, and so the impact on the game was the subject of much conjecture, with FIFA doing their best to deny that it would have any impact.  Many people felt it would impact on players, and  I hypothesized a number of changes in matches caused by altitude.  The overall summary is that players would cover less distance and also sprint less.  The impact of altitude would be to slow the game down - the comparison I gave is that footballers in top-level competition (Italian Serie A) run and sprint more than footballers in lower level (Danish) leagues, with less rest relative to work.  The altitude would have the effect of bringing the level down.

Now, thanks to Castrol's sponsorship of FIFA, we can actually evaluate that hypothesis, at least partly.  For those who don't know, Castrol are one of FIFA's eight 'middle level' sponsors, and they have been doing technical analysis of matches as part of their sponsorship activation strategy (I won't go into the details now).

So every match is tracked using cameras and all kinds of statistics are produced.  How far players run, how many passes they attempt and complete, tackles made and missed, number of sprints attempted and so forth.  I must confess that I can't vouch for the accuracy, and I've tried to email them to find out more about how the data are collected.  I've yet to hear back, but I think it's important to stress that there probably will be some error in the data - there always is.   However, I think the data they've produced is quite compelling, and as you'll see, the differences are large.

Altitude - less sprinting, less high intensity distance

The table below is a summary of the data on distances run and sprints attempted during the Round 1 matches.  There were 29 altitude matches and 19 sea-level matches, meaning that there are values for 38 teams at sea-level and 58 at altitude (I've treated Nelspruit as sea-level, incidentally, at 600m).

The distances covered by teams in matches are looked at for TOTAL DISTANCE, DISTANCE AT LOW INTENSITY (walking and very slow jogging - the average speed in this zone is 4.5 km/h, which is walking pace), and DISTANCE AT HIGH INTENSITY.  The average speed in this zone is 16 km/hour, but in some matches, were more high intensity running was done, it gets up above 20km/hour.

So, the total distance covered per match is reduced by 4% at altitude.  What is more interesting is that the low intensity distance is only 0.2% lower (statistically it is the same), but the distance covered at high intensity is down by a pretty large 11.5%.  The distance of 25,106m at altitude is 2,750m lower than at sea-level, and assuming that the goal keeper contributes negligibly to the high intensity distance, this equates to about 275m less sprinting and high speed running per player per match.  Of course, some players will be affected more than others, and so it's quite conceivable that certain players have covered a kilometer less at high speeds at altitude.  That is a massive difference - about 30%, and may impact on match outcomes.

This is further reflected in the number of sprints - down 11.5% from 1,059 to 949 sprints per match.  That's about 10 sprints per player per match less, which makes up most of that 275m per player difference.  Note that I've cut out the medium intensity running distance from the table - the distances there were 16,890m for sea-level and 15,819m at altitude, so again, there is a reduction in distance at altitude.  I'm emphasizing the extremes though.

The point then is that altitude slows the game down at the "top end", reducing the distances covered in sprinting as well as the number of sprints by about 11%.  That is a significant difference.

What the data doesn't allow us to do, unfortunately, is to decipher whether the reduction at altitude is produced entirely in the second half as players fatigue, or whether they slow down right from the onset and pace themselves differently.  I would lean towards the latter, and suspect that the distances covered are reduced at altitude from the very first 15 minutes of matches.

Individual match variability

I must also point out that there is a chance of a false conclusion here because although the differences are large, there are many confounding factors too.  For example, the match between Switzerland and Spain in Durban produced the most running of any match in the tournament.  The Swiss covered 119,909m in that match, of which 39,256m was at high intensity, at an average speed of 22 km/hour, and consisting of 1,484 sprints!  This was the most of any team in any match in the tournament (for interest's sake, the highest total distance was by Australia in their match against Serbia - 121,506m).

However, not far behind this was South Africa's opener against Mexico, but this was in Johannesburg.  There, SA covered a total of 118,856m, and 37,312m was at high intensity, with 1,690 sprints.  So here we have two games with similar distances, but one is at altitude and the other at sea-level.  To emphasize this point even further, consider France in their match against Uruguay in Cape Town.  There, they covered only 101,499m in total, with 25,320m at higher speeds.  So, that sea-level match had 50% LESS high intensity running than an altitude match...the graph below summarizes these three teams' physiological profiles.

The point I want to emphasize is that the tempo of the match, and the distance covered is not solely determined by the altitude - the strategy of the teams and also the nature of the match influences it as much.  The France v Uruguay match was particularly "narrow" with little movement because of the strategy of the two teams, and so less running was to be expected, compared to the Swiss who chased and worked tremendously hard off the ball against Spain.  However, on the balance of 58 altitude performances and 38 sea-level performances, altitude has exerted a significant effect, 11%, on the nature of the matches.  Perhaps another 50 matches would remove this 'randomness', but I'm quite convinced by the finding.

It's especially compelling, as I mentioned, if you consider that some players will be affected more than others, and with the possibility of 30% reductions in sprinting distances, the altitude has certainly had an impact.

When are goals scored?  Could altitude affect goal-scoring?

The next question related to this is whether the timing of goals scored differs between altitude and sea-level?  The reason one might hypothesize this is two-fold:
  1. There is already plenty of evidence that more goals are scored in the final 15 minutes of matches than in any other fifteen minute period.  In fact, over 20% of a match's goals are scored in the final 15 minutes, according to a study by Armatas et al.  This has been attributed to fatigue at the end of the match, since players certainly slow down as the game progresses.  I suspect there is more to it than this - concentration, the state of the game, the intent of players as the final whistle approaches are all factors, but certainly, the final 15 minutes produces more goals.
  2. Altitude will have a greater effect on fatigue (and thus potentially concentration), and so if the trend is observed at sea-level, the theory might be that altitude exaggerates it even more.  That is, one might suggest that more goals will be scored in the latter part of matches at altitude than at sea-level.
This is of course quite easy to determine - you simply have to count the number of goals scored in each 15 minute period.  The tricky part is knowing whether it's just co-incidence, because it's very easy to read too much into it and come up with 'patterns' where there are none!

I've done this, counted all the goals scored, and I have this result.  However, it is for another post, because this one has given out enough numbers for one day, and besides, there's work to be done!

So next time, we'll look at when goals are scored, and whether there's a chance that altitude affects it!

Join us then!

Friday, July 02, 2010

Football - the world's most immoral sport

Football:  A sport where morals and ethics are irrelevant

Tomorrow is the start of the Tour de France.  For the next three weeks, media coverage will comprise a mix of adulation and condemnation.   Adulation for the efforts of men who propel themselves over 3,000km of mountains, cobbles and windy flat roads in the world's most demanding sporting event.  And condemnation because all the while, people will question the validity of their performances.  Are they doped? To what extent does success in cycling equate with success at avoiding doping controls?

And here on The Science of Sport, we've been as harsh as anyone on the sport of cycling.  And with reason.  Cycling has a problem of its own making, and its refusal to address its own problem eventually led to media and sponsors threatening withdrawal.  And only then, amid much kicking and screaming, did cycling begin to turn a corner.

Cycling is still burdened by its doping past, make no mistake, and the legacy of its "great" champions means it will forever be questioned - again, this is a deserved reputation.  But it has certainly improved - the efforts of the biological passport and the invasive testing and the sponsors have gradually begun to control the extent of doping in the peloton.  As we will see over the next few weeks, the power outputs produced by the winners are coming down.  They are now "physiologically believable".  And for this, anti-doping efforts deserve some credit.

However, today, I felt the need to comment on another sport, which is, without doubt, more corrupt, more fraudulent and more immoral than cycling.  That sport is football - a sport that is completely without morals and an ethical code. 

This is a post I've been meaning to write for some time.  Ever since the World Cup began, I've commented on the irritation I feel at the diving, the play-acting, the cheating and the open dishonesty of players.  The referees are part of a 'script' that rewards this cheating, and the game is poorer for it.  And then just the other day I was having a conversation with a good friend of mine, and he was sharing that he finds it impossible to enjoy watching football, because the fraud leaves such a bad taste in the mouth.  And as the tournament has progressed, I find myself more and more in agreement.

A rugby paradigm applied to football - it just doesn't work

My friend Colin comes from a rugby background, a sport which still has values.  And I think it's important for people reading this to appreciate that if you are from a rugby background, the notion that a player will charge up to a referee and insist on a yellow or red card is completely foreign.  In fact, the notion that players will even challenge a refereeing decision is unheard of in rugby.

A player who goes down and exaggerates the extent of an injury to gain an advantage would be ridiculed in rugby.  In football, he is celebrated.  In football, referees command absolutely no respect from players.  They are tools to be deceived rather than officials to be respected.  And before you point out that basketball shares this trait, do yourself a favour and watch 58 games of World Cup Football, and you will see the difference.

Football is a disgraceful fiasco which rewards cheating, even glorifying it. And I enjoy watching football, but I cannot bring myself to respect it.  The fervor of the fans, the passion, the colour and the celebration of skill make the sport worthy of watching.  However, the shenanigans around cheating, and the glorification of that cheating, destroy my respect for the sport and its players.

From the first whistle to the last, players in football will seek to gain any advantage, no matter what level of cheating it requires.  If two players are attempting to win the ball near the sideline, and it ricochets off one of them, then BOTH will appeal to the referee for a throw-in.  One of them is lying, and thus cheating.  Yet it happens 100% of the time.  If a player is tackled, he will go to ground.  Guaranteed.  And the referee will react, also guaranteed.   Today, in the Brazil v Netherlands match, Arjen Robben launched himself over the tackler with a clearance that the Olympic high-jump champion would be proud of.  The referee bought it, awarded the free-kick, and the game changed from that point.  This is not an isolated incident.  Penalties are won by dives, players are sent off thanks to play-acting (just ask the Ivory Coast for their diabolical cheat against Brazil), and generally, matches resemble the WWE more than they do a competitive sports event.

The other day, I completed a survey being done by researchers in the UK, looking at public perceptions of cheating in football.  The survey wanted to know my thoughts on whether the behaviour is cheating, and whether it is typical of the sport, or whether only certain teams do it.  The answer is that it's pervasive.  Every team, and most players, will seek to gain any advantage by cheating.

What is the difference between football and cycling?

And the tragedy is that the media glorifies it, the fans idolize it, and in general, it is praised rather than condemned.  Now, I can't see the distinction between this cheating and what happens in cycling.  I don't see how diving to win a free-kick or get an opponent sent off is any different to manipulating the system to get away with doping.  Yet it one sport - football - it is glorified, while in another, it dominates conversation.  Quite why this is is beyond me.

Cycling is a sport that, for all its faults, still has some code of behaviour that makes it almost noble.  If the race leaders crashes, the peloton waits, even if the Tour is at stake.  The group agrees to slow down for feeding stations and bathrooms breaks.  And sure, there are occasions where personalities affect the behaviour of the peloton (the Simeoni incident with Armstrong comes to mind as an ugly incident).  But in general, cycling is a peculiar mix of cheating through doping and honesty and sportsmanship.

In football, there is no redeeming value.   The most celebrated footballers of the current World Cup are its most celebrated primadonnas.  Ronaldo dived more two in three times that he ran with the ball.  Didier Drogba collapses like a matchstick man when he feels the breath of an opponent on him.  Arjen Robben exerted himself more rolling on the floor than he did running.  Yet these men are superstars.  They should be jeered off the field in disgrace.

If I were a footballer (and I played a little in my time), I would be so irate at the first opponent to tries to cheat by diving that I'd be liable to lash out at him and get myself sent off. Yet it happens all the time and collectively, the sport embraces it.  Referees must take much of the blame, but ultimately, FIFA are responsible for the decay of the sport into this realm of immorallity, cheating and dishonesty.

And frankly, it is shameful.  It devalues the sport and its athletes.  Yet FIFA is entirely complicit, because retroactive censure for these players could go a long way to stamping it out of the game.  Most footballer followers are equally complacent - they shrug their shoulders and accept it.  "It's part of the game".  Referees buy it, all the time.  FIFA does nothing to prevent it.  And players exploit the system.

Ultimately, football may be the "beautiful game", but given the degree of fraud and cheating that goes on in it, it is the immoral game.  There is no beauty in what we have seen in the first 58 games of this World Cup, only the sour taste that  remains when you've consumed something that should taste good, but for some reason, just tastes spoiled.


Thursday, July 01, 2010

Cycling performance: What is possible?

The limit to cycling performance: Can physiology flag doping?

Yesterday I posted on the upcoming Tour de France, and made mention of a topic that I feel is:
a) Really interesting as a means to add value to watching the sport, and
b) Potentially interesting as a means to flag suspicious performances.

And rather than wait until the Tour begins, I thought I'd take advantage of a rest day in the FIFA World Cup to get some thoughts going, since I left yesterday hanging somewhat (deliberately, but still...)

And so here are some thoughts on the ability of performance to predict physiology.

Estimation and assumption

Perhaps right up front, I have to talk briefly about estimation and assumption vs measurement.  Of course, the ideal would be to get accurate SRM data on the power output on the climbs.  Of course, it would be wonderful to know with precision what the power output was, but as I hope to illustrate, the errors in these kinds of calculations can both be minimized and controlled so that you end up with a 'best case scenario".

This is much the same situation you would find yourself in if, for example, you wanted to open a coffee shop and had to do prepare a business model.  You don't know how many cups of coffee you'll sell, you don't know how many biscuits to bake.  But if you know your market, and its people (your future customers, you hope), then you can control your assumptions and go a long way to making a conclusion.  That is, if you make "best-case" assumptions and still your coffee shop is running at a loss, then it clearly is not a viable business.  If your "worst-case scenario" (few customers, few sales) still makes a profit, then the business works.  Realistic and sensible assumptions are the key to ensuring that your conclusion is accurate, even in the absence of a crystal ball!  Similarly, for these physiological calculations, you can make "best-case" assumptions and if the picture still doesn't fit, then you have a good case for a problem.

So over the next few weeks, I think we must acknowledge right away that these are always estimations - of power output, of body mass, of bike mass, of wind speeds and directions - all these factors will affect the eventual physiological calculation, but for two reasons, their effect is not as large as you might think:
  1. We're not proving anything here - only suggesting physiology for the purposes of increasing enjoyment and stimulating discussion, and 
  2. The physiological implications are so large that even errors don't affect the conclusion.
So let's say it now, one last time - this is not proof, but an interesting exercise nonetheless, and I believe a compelling way to approach the problem.  Ultimately, people will believe what they wish to, even when presented with a 'creaking and ugly edifice'.

So let's get cracking...

An extreme case - the physiological implications of 8 W/kg for 40 minutes

Let's take a rider who produces 8 W/kg.  Assume his mass is 70kg, which means an absolute power output of 560W.  Clearly, very high.

In order to work out the physiological implication, by which I mean the oxygen cost, there are two potential methods.

The first involves the use of a published paper called "Peak power output predicts maximal oxygen uptake and performance time in trained cyclists".  This study looked at 100 trained cyclists and established the following relationship between oxygen consumption (VO2) and power output.  The relationship is:

VO2 (L/min) = (0.01141 x Power output) + 0.435

Therefore, if you take the power output of 560W, and you apply this equation, you will calculate an oxygen consumption of 6.82 L/min.  Relative to body mass, this is equal to 97.49 ml/kg/min.

The second method, just for comparison's sake, requires that you do three things:
  1. You calculate the real energy cost of producing that power, by taking advantage of the fact that cyclists are not perfectly efficient.  In fact, elite cyclists are only about 23% efficient.  What this means is that a cyclist who is riding at 560W is in fact producing 2435 W.  Clearly, we now have our first assumption - the efficiency.  Lance Armstrong's efficiency was measured as 23.12%.  Other studies find values that range between 21% and 27%, though values over 25% are hotly debated, and basically dismissed as an artefact of testing and equipment.  This is a controversial issue, but most elite cyclists seem to be around this 23% value, and since Armstrong's was measured there, I'll use it for the remainder of this calculation.

  2. The total energy can now be used to work out an oxygen consumption.  This requires that you have knowledge of the contribution of various energy stores to the physiology.  We know that every liter of oxygen used produces between 4.69 kCal and 5.05 kCal, depending on whether fat is being used, or carbohydrates.  So, this is our next assumption - which end of this spectrum do we use, the 4.69 or the 5.05kCal?  The answer is the further right extreme, for two reasons.  One is that it's physiologically reasonable - a cyclist producing maximum effort is going to be near maximally using carbohydrates.  Second, this is the "conservative" or "best-case" assumption, as explained earlier.  So we'll run with 5.05 kCal/L O2.

  3. We can now work out the oxygen consumption for a given power output at a given efficiency.
In our example, 560 W produces an oxygen consumption of 6.91 L/min, or 98.71 ml/kg/min.

You'll note that this is similar to the value of 97.91 ml/kg/min that we calculated using Method 1.  This suggests that the above assumptions of efficiency 23% and energy use per liter of oxygen are correct.  I must point out that we haven't yet considered the contribution of non-oxygen dependent pathways (the so-called anaerobic contribution) to energy.  This is of course important, but I would also point out that we are talking about a cyclist who is producing this power output for 40 minutes at the end of a 5-hour cycling day, and so the assumption on energy demand, given the length of exercise, is still valid (in my opinion).

Now, what do you make of that oxygen consumption of 97.9 ml/kg/min?  If I measured it in the lab, I'd be checking my equipment...clearly, something is wrong.  And if a cyclist were able to produce that power output (8 W/kg) for 40 minutes, with that physiological implication, then you'd be calling him out (or you'd be looking for the electric motor in his pedals).

If you assume, for example, that a cyclist can maintain 90% of their maximal level for 40 minutes, then this oxygen use of 97.9 ml/kg/min corresponds to a VO2max of 110 ml/kg/min.  The red flag is clearly waving.

So when is it possible for a cyclist to ride at 8W/kg, assuming they have a VO2max of 80 ml/kg/min?  Well, their cycling efficiency would have to be around 32% - many percent higher than anything ever measured before.  9 W/kg, which I throw out only because it was suggested is possible on a chat forum, would require that a cyclist with a VO2max of 80 ml/kg/min is 35% efficient.  Either that, or a cyclist with an efficiency of 23% would have to have a VO2max of 123 ml/kg/min.  It simply doesn't happen, and therefore, neither do 8W or 9W/kg for 40 minutes.

Now, let's look at a much more conservative assumption - the decent level cyclist...

The "low end" - 4 W/kg for 40 minutes

Most trained cyclists would be able to produce this power output.  In our lab, we test the range of beginners to elites, and this what you would expect of a decent level cyclist.  And we know that a decent cyclist will produce a VO2max of around 60 ml/kg/min.

Using the same method as before, we can estimate that the oxygen consumption associated with this performance of 280 W is equal to 51.9 ml/kg/min.  If you prefer method 2, using an efficiency of 23%, then you'll calculate 49.4 ml/kg/min.  The reason this is lower, incidentally, is because this person is unlikely to have an efficiency of 23%, but one that is lower than this.  If we use 22%, for example, we calculate 51.6 ml/kg/min.  Again, this shows that 23% is a pretty safe "best case" estimation.

Again, if you assume that a rider such as this is maintaining 90% of max, then the inferred VO2max would be equal to 57.6 ml/kg/min.  That's a perfectly reasonable value.  If anything, it's on the low side, which I again point out shows that the assumptions I'm making for all these calculations are "conservative".

The key assumption in this regard is the 90% of maximum assumption.  In reality, a good level cyclist will ride at 85% of maximum, which means our inferred VO2max suddenly rises to 61 ml/kg/min.  I also maintain that a Tour rider, on the final climb of the day, will be closer to 85% than 90%, given that they've been riding for five hours.  However, this assumption is debatable.  My point is, if the physiology is still unrealistic with these safe assumptions, then you know you have a problem.

So now, we've looked at two extremes - the high, which simply doesn't exist, and the low, which is safe and clear and maybe even a little conservative.  There is a point in between, where elite Tour riders exist, where the really interesting questions begin.  So let's look at a Tour rider...

Bjarne Riis - 6.8 W/kg for 35 min on Hautacam.  Or Armstrong - 6.6 W/kg for 38 min on Alp d'Huez

Bjarne Riis is estimated to have produced 6.8W/kg (480W) on Hautacam when he won the Tour in 1996.  Armstrong's estimated power output on Alp d'Huez was 6.6 W/kg (465W).  This is Vayer and Portoleau's estimation, and I believe it to be accurate.  I actually saw a PhD student from Texas present a similar analysis at the ACSM conference in 2005, and he had worked out 495W (7 W/kg), taking into account the gradient every 100m as well as wind speeds.  If anything this is more accurate.  But as I mentioned, we'll be "conservative" in our calculations, so let's take the lower option and see what it means, physiologically.

We again assume 23% efficiency (in Armstrong's case, this is not an assumption - it was measured by Coyle), and we can calculate that the oxygen cost of producing 465 W is equal to 81.96 ml/kg/min.  Using method 1, the equation from the published literature, we find oxygen use of 82.00 ml/kg/min, pretty much identical.

Now, is it possible to ride at 81.96 ml/kg/min for almost 40 minutes?  If you are at 90% of maximum, then it means that the VO2max must be equal to 91.07 ml/kg/min.  If you are at 85% of maximum, then the maximum must be 96.42 ml/kg/min.  Given that by the time these performances happen, the cyclist has been in the saddle for five hours, not to mention about 2 weeks before, I feel pretty safe in saying that you're projecting a VO2max that lies somewhere between 91 and 96 ml/kg/min, probably closer to 96 ml/kg/min.

Another example comes from Armstrong's own words.  In this interview, he says "I also cranked out 495 watts for more than 30 minutes".  495 W is about 7W/kg, and applying the same equations as I've done throughout this post, you can work out that it requires oxygen consumption of 87 ml/kg/min, and a VO2max of 97 ml/kg/min (and that's at 90% of maximum.  If you go with 85%, you get 103 ml/kg/min...).  

Is that realistic?  I suspect that your answer to that question depends not on what you know, but rather on what you want to believe.  I don't believe that it is possible, because the combination of high efficiency (and 23% is high) and high VO2max doesn't seem to exist.  In fact, Lucia et al showed that there was an inverse relationship, so that those with the best efficiency had the lowest VO2max. So the problem is that if you suggest that we increase the efficiency to make the predicted VO2max come down, you're chasing the pot of gold at the end of the rainbow, because the possible VO2max is coming down anyway!

However, people will draw their own conclusions.  I am of the opinion, like Prof Aldo Sassi, that a value above 6.2 W/kg is indicative of doping.  And in the coming weeks, I will post more on this, including graphs that hopefully illustrate this point even more clearly.  But, as always, there is likely to be debate.

Next up - the Quarterfinals

That's it for cycling for now - during the course of the Tour de France, we'll return to this kind of approach and look at some of the performances, and compare them to historical numbers.  As always, the discussion is welcome.

The cycling now gets put on hold for a few days while the Football World Cup Quarter Finals take place!  I am sitting on piles and piles of data about how far players run at different altitudes, and even how goalscoring seems to be affected by the altitude.  But perhaps for two days, I will be a fan, and then resume the analysis next week!

Oh, and there's Wimbledon!  And the start of the Tour!  Enjoy it, and we'll be back soon!