30 July 2012

Mexican Spins

I had to let my 8-year-old daughter stay up late tonight and watch replays of today's Olympic action.  I knew the outcomes, and had seen some of the events online, but did not spoil my daughter's anticipation.  First, we watched the final of the men's 10-m synchronized platform diving (more on that in a moment).  Then, we watched Misty and Kerri stay undefeated in beach volleyball.  Finally, we watched swimming, capped off with Missy Franklin's gold-medal performance in the 100-m backstroke (click here for my last blog post on that).  Seeing the Olympics through the eyes of a physicist is a blast, but that pales in comparison to watching my daughters root like crazy for women whose names were unknown to my girls just a week ago.

Okay, back to the men's 10-m synchronized platform diving final.  The Chinese team of teenagers Cao Yuan and Zhang Yanquan looked almost mechanical they were so good in winning gold.  What really caught my eye, however, was the silver-medal team of Iván García and Germán Sánchez from Mexico.  Their 4th dive earned the highest score of all teams, partly because they executed it so well, and partly because of the extreme difficulty of the dive.  With a degree of difficulty of 4.1, they executed an inward 4 1/2 somersault tuck.  Think about that for a moment.  They turned four-and-a-half times from a height of only 10 m (33 feet), and they did it after starting at the end of the platform, i.e. no walking start.

Simple one-dimensional kinematics tells us that a point mass dropped in vacuum will fall 10 m in 1.43 s.  A diver's center of mass starts higher than 10 m, but that is somewhat compensated by the fact that the diver's fingers enter the water while his or her center of mass is still out of the water.  Divers jump from the platform, so they do not simply fall from rest, and there is a small amount of air resistance to slow divers during their descent.  Expect, therefore, a time of flight greater than 1.43 s.  An NBC broadcaster claimed the time of flight for the Mexican team on their most difficult dive was 1.92 s.  Still-photo replay of the dive indicated that by 5 m (16 feet) above the water, the divers had begun to straighten out for entry into the water.

I'll do a quick vacuum calculation.  To avoid hitting the platform, divers must have a small component of their launch velocity be parallel to the water and away from the platform.  I estimate 84 degrees as measured from the horizontal.  Taking the net center-of-mass drop to be 10 m by the time their fingers hit the water, the launch speed for the Mexican team would have been 4.22 m/s (15.2 km/hr or 9.45 mph).  By the time they hit the water, they were about 85 cm (2.8 feet) horizontally from the edge of the platform.

How much time had passed when they were straightening out at about 5 m above the pool?  Roughly 1.53 s had elapsed, leaving them with just 0.394 s to straighten out and enter the water.  In that initial 1.53 s, they had executed four somersaults.  That works out to an angular speed of 2.62 rev/s or 157 rpm.  Now that's fast!

As for how those talented Mexican divers were able to execute those wonderful spins, look for another post from me in the not-too-distant future.  Big hint:  angular momentum will play an important role!

Why is Missy Franklin so good?

Missy Franklin turned 17 this past May and was many people's (including me) pick to snatch up some gold in London.  She won her first Olympic gold medal today after setting the American record in the 100-m backstroke with a time of 58.33 s.  Why is she so good, besides a great work ethic and fantastic trainers?

First of all, Miss Franklin is a tall female at 6' 1.5" (1.87 m).  More importantly, she has a wingspan of 6' 4" (1.93 m).  For most "normal" people, our wingspans are about the same as our heights.  Those long arms provide increased leverage, meaning they shovel more water out of her way with each stroke than what "normal" people can shovel.  At 6' 4" (1.93 m) tall with a 6' 7" (2.01 m) wingspan, Michael Phelps has a similar advantageous build.

Franklin's lengthy torso acts like a boat's hull in the water.  Watch her when she swims underwater and you'll see her long legs undulating in a way similar to how a dolphin propels itself through the sea.  Franklin also has large hands and feet (size 13).  It's hard not to think of flippers when you watch those hands and feet in action in the water.  For comparison, Michael Phelps wears size 14 shoes.

We live in a age in which training methods have become imbued with the latest scientific advances.  Better equipment, nutrition, and health care have helped athletes push the envelope of what humans can achieve in athletic competition.  There are an elite few, like Missy Franklin and Michael Phelps, who posses a genetic makeup that gave them bodies almost perfectly suited for their chosen sports.

The final of the 200-m backstroke is this Friday.  Are you going to bet against Miss Franklin?!?

29 July 2012

Vollmer on the Fly

My girls and I rooted on Dana Vollmer of the US as she set the world record in the 100-m butterfly with a time of 55.98 s.  My younger daughter, age 6, said during the race, "They don't seem to be going that fast."  Perspective is everything!  To fully appreciate those elite athletes in action, cameras move with the swimmers so that we have an idea what the stroke action is like.  Moving along in someone's reference frame obviously makes it difficult to appreciate how fast that person moves with respect to the Earth's surface.

I asked my daughter if she could walk faster than Vollmer was swimming.  My daughter said, "Yes!"  Maybe, but then again, maybe not.  Average walking speed is roughly 5.0 km/hr (1.4 m/s or 3.1 mph).  Very young children and older people walk within 0.5 km/hr or so slower than that; fit teenagers and adults within 0.5 km/hr or so faster than that.

How fast was Vollmer?  Without getting too technical and analyzing the details of the entire race, simply calculate her average speed.  Covering 100 m in a time of 55.98 s gives an average speed of 1.786 m/s, which is 6.431 km/hr or 3.996 mph.  That speed is actually a bit slower than power walking, which is around 8.0 km/hr (2.2 m/s or 5.0 mph).  My 6-year-old daughter is not likely to keep up with Vollmer's record-setting butterfly pace -- unless she started to jog.

Don't be fooled by cameras moving along with elite swimmers.  Those athletes can fly!

Sabres and Bikinis

One thing I truly enjoy about the Olympics is the opportunity to watch sporting events I seldom see -- and seldom seek.  Much of my viewing right now is governed by what my two young daughters want to see.  They love watching the female competitors, especially the gymnasts, the swimmers, and, just recently, the beach volleyball athletes.

My older daughter, age 8, loves watching beach volleyball, and we've seen a good bit of the preliminary action. She had fun rooting on Misty (May-Treanor) and Kerri (Walsh) as they beat Australia.  We also saw Italy beat Russia.  My daughter was rooting for Greta (Cicolari) and Marta (Menegatti) as much as she rooted for Misty and Kerri!  Ball speed was given a few times, and I thought I'd do some calculations because I've not played with volleyball much, though I have seen the drag coefficient curve for a volleyball.

A beach volleyball weighs about 2.65 N (0.595 pounds).  One serve by one of the Italians was clocked at 60 km/hr (16.67 m/s or 37.28 mph).  That speed corresponds to a Reynolds number a bit greater than 240,000 -- almost past the drag crisis.  The drag coefficient at that speed is a tad larger than 0.11.  The initial drag force on the Italian's serve was roughly 0.69 N (0.15 pounds), or 26% of the ball's weight.  The buoyant force on the ball, which is due to the fact that the ball's volume displaces air, is only about 2.3% of the ball's weight.  Serves that have very little spin look to have a "knuckleball" effect, meaning they wobble due to varying asymmetric shedding of the boundary layer, which comes about because of the smooth and rough areas on the ball.

A newcomer to beach volleyball, I found the competition fascinating.  Athletes have sophisticated strategies for play, and they have amazing reflexes.  It boggled my mind how they were able to get to some of the smashes!  I also saw quick reflexes on display in a sport with which I am even less familiar than beach volleyball -- fencing.

The men's sabre competition was exciting to watch.  Áron Szilágyi of Hungary defeated Diego Occhiuzzi in the final.  I confess that I know very little about fencing.  I was stunned how fast each point was earned -- not the sabre duels I see in movies!  Lightening quick reflexes lead to swift strikes, and I learned that sabre duels are quick because athletes may score with the blade's edge, in addition to the sabre's point.  Szilágyi was clearly the elite of the competition and well-deserving of his gold medal.  I especially like the class he showed after the penultimate point in the final match when Occhiuzzi looked to have a cramp or pulled muscle in his leg.  Szilágyi showed genuine concern for his opponent.  Great sportsmanship!

I try to watch as much of the Olympics as I can, but there are only so  many hours in the day.  I also have a life outside sports!  Today was about spending time with my daughters and taking delight in their enjoyment of the London Olympics.  Sabres and bikinis are about as far apart as one can get, but the athletes associated with each taught me something new about their respective sport.

28 July 2012

Millimeters Between Archer Gold and Silver!

The final of men's team archery was a nail-biter!  Let me set the stage.  The powerful South Korean team set the world record in the ranking round with a score of 2087, hitting 145 bulls-eyes (67.13% of their shots).  The US team finished 4th; they tied China, but the Chinese team had one more bulls-eye.  Italy was seeded 6th and had to compete in the first round; US and Italy had first-round byes, along with South Korea and China.  The Italians stunned China in the first round with a 220-216 win; the US team knocked off South Korea in the semifinals with an impressive 224-219 victory.  The South Koreans had just taken out Ukraine in the quarterfinals with an Olympic record-tying score of 227-220.  Italy beat Mexico in the semifinals after Mexico upset the #2-seeded French team.  It was US vs Italy for the gold.

Archers stand 70 m (230 feet) from their target.  The bulls-eye, which is worth 10 points if hit, is just 12.2 cm (4.80 inches) in diameter.  That means that if an archer is able to sight perfectly the center of the bulls-eye, there is only 0.05 degree (1/20th of a degree or 3' of arc) margin of error to the left or right.  That the South Koreans hit two out of three bulls-eyes in the ranking round was incredible!  Throw in the London wind that was present for all competitors, and hitting the bulls-eye is even more impressive.

Italy entered the final round of the gold-medal match just one point ahead at 192-191.  The US went first.  Jake Kaminski hit an 8, followed by Jacob Wukie's bulls-eye.  Brady Ellison then hit a 9, just a millimeter or two to the left of the 10 line.  The Italians followed with Mauro Nespoli's 9 and Marco Galiazzo's 8.  They were down 209 to 218 with Michele Frangilli coming up for the final shot.  His last shot was an 8; now a bulls-eye would mean gold for Italy.  He coolly sighted his target and fired.  His shot hit the line on the left of the bulls-eye, only a millimeter or two better than Ellison's shot.  That was the difference between gold and silver as the Italians beat the US, 219-218.

As a side note, there is a cute energy calculation you can do for archery.  Each participant shoots 72 arrows during the ranking round.  The recurve bows they use have the distinctive outward curve at the edges of the bows.  Recurve bows are quite efficient at about 85%.  Before each shot, the bow stores about 60 J of energy.  Estimating the energy conversion in the archer's body to be 25% efficient, archers expend about 17.3 kJ during the ranking round.  That is equivalent to roughly 4 Calories, which is the nutritional energy content in a Diet Coke.  So, when I see archers competing in the ranking round, I see a can of Diet Coke!

Great Move, Vinokourov!

Not too far before reaching the 200-m-to-go sign, Rigoberto Urán was headed for gold -- and then looked over his left shoulder.  That little hesitation by the 25-year-old Colombian was all the opening that 38-year-old Alexander Vinokourov of Kazakhstan need to slip into the gold-medal position.  It was a great move by Vinokourov!

Vinokourov's gold-medal winning time was 5h 45' 57" over the 250-km (155-mile) road race, giving him an average speed of 12.04 m/s (43.36 km/hr or 26.94 mph).  That's a great average speed for a distance 24 km (15 miles) longer than the longest stage in this year's Tour de France.  Based on how I calculated calories burned for the Tour de France, I estimate that Vinokourov burned about 8000 Calories in the biking-only part of his effort.

I felt really bad for Fabian Cancellara of Switzerland.  With just over 10 km (6.2 miles) to go, he was leading the race and heading into a tight turn to the right.  He crashed to end his gold-medal dream.  As he entered the turn, Cancellara was not leaning enough into the turn and, hence, was not allowing his bicycle's tires to push out to the left with enough force to allow the road to push his tires to the right.  As one moves in a circle at constant speed, the inward, or centripetal, acceleration is proportional to the square of the speed and inversely proportional to the turn radius.  If the inward force is not large enough for a given speed, a larger radius is needed.  That's why Cancellara crashed.

Great Job, London!

I confess that I felt like an idiot when 4:00 pm rolled around and I had just made it home to watch the opening ceremonies.  The Tour de France had so absorbed me that I did not pay attention to the fact that NBC followed the usual greedy and solipsistic path taken by a major US broadcaster that covers the Olympics.  Instead of deferring to a host country's schedule, NBC chose to delay its broadcast of the opening ceremonies by three-and-a-half hours.  Those more media savvy that I in the US might have found a way around NBC's efforts to control when and how we view the Olympics.  Kudos to you if you did.  My girls and I had to wait until 7:30 pm before Olympics coverage began.  The one spectacle my girls most wanted to see was their home country's athletes in the parade of nations, which NBC turned into a parade of commercials for much of it.  The US team walked out at 11:02 pm on the east coast, roughly three-and-a-half hours after NBC's broadcast began.  Had we watched it live, my girls could have seen the US team by the time the NBC broadcast began showing anything.  They simply couldn't keep themselves awake.  Please excuse my sour grapes.  DVR and internet streaming are fantastic technologies.  Anyone not home from work by 4:00 pm on the east coast of the US  (earlier as one moves west) could have recorded the opening ceremonies.  Of course, they most likely would have fast-forwarded through all the mindless commercials.

The NBC converge is what it is, and that's my final rant on that topic.  Despite NBC's delay, London put on a wonderful show tonight.  It was a visual masterpiece that showcased human solidarity.  I really enjoyed the tribute to the UK's National Health Service, which, as I discovered while living in England during my last sabbatical, the people of Britain take great pride in.  Many, many articles, blog posts, television stories, etc will be devoted to the brilliant and wondrous show London put on as it opened its third Olympics.  My guess is that several of those pieces will highlight the great diversity on display in London's Olympic Stadium.  What tickled my mind while watching the opening ceremonies unfold was actually the continued realization that we all share common ancestors.  Each and every living thing on Earth, everything with DNA that is, share a kinship with one another.  Human beings doing great science over the past century and a half have provided us with that awe-inspiring fact.  The notion of race is antiquated, at least from a scientific point of view.  Seeing fellow human beings from just over two hundred nations from around the globe provided me with a warm sense of human solidarity.

Let the games begin!

27 July 2012

The London Olympics are here!

Opening ceremonies are just a tad more than five hours away.  I can't wait!  My two girls and I have a date for 4:00 pm (Eastern Standard Time) in front of the television.  I hope to write a few blog posts during the Olympics that touch on how a physicist like me views the various sporting events.  For more on this topic, I invite you to read my invited blog post over at Johns Hopkins University Press.  Click here for the general blog page or here for the specific link to my post.

Lots of great sporting moments ahead!

25 July 2012

Tour de France Energy

Check out the graph below (click on the graph for a larger image).
I took my model's cyclist and computed the energy output needed to cycle through each stage of this year's Tour de France.  I then estimated the body's energy efficiency for cycling to be 20%.  Some muscle groups are more efficient, some less efficient.  Anyway, 20% is a reasonable estimate.

Keep in mind that what I plot in the above graph is the energy burned just to ride the bicycle.  I do not include any estimate of normal metabolic rates and energy burns needed to stay alive.  Based on our body temperature and energy exchange processes in our bodies, we are all similar to 100-W light bulbs.  Burning energy at that rate is why we need something like 2000 Calories per day to maintain a constant body weight.  The graph I give above does not include that 2000 Calories; it shows only the energy a cyclist needs to burn in his body to perform the mechanics of riding the bicycle through each Tour de France stage.

Think you can compete in the Tour de France?  One slice of a 14-inch Pizza Hut pan pizza supreme contains 290 Calories.  Over a three-week period, you would have to burn the equivalent of 425 slices of that Pizza Hut pizza, which works out to about 20 slices per day.  Of course, top athletes don't eat from Pizza Hut while competing in the Tour de France, but they still have to replace all those Calories they burn.  The two rest days during the race are necessary to help cyclists make up for any lost Calories.

Energy conversions in the body are complicated (see Chapter 9 of my book).  Carbohydrates and fats are the usual sources of energy with the former delivering energy at a faster rate than the latter, which is why athletes like to burn carbohydrates.  If, however, you could magically lose only fat while biking during the Tour de France, consider that a pound of fat contains roughly 3500 Calories of chemical energy content.  Three weeks of Tour de France cycling would then burn off about 35 pounds of fat, if you had that much in reserve.  The problem is that if you have 35 pounds of fat to lose, it's not likely you'll be able to ride in the Tour de France!  Only the best of the best can burn calories like what you see in the above graph.

Is completing the Tour de France the toughest thing to do in sports?

24 July 2012

Thank You, Sally Ride

It is past midnight as I type this, meaning that Monday has given way to Tuesday here in Virginia.  I am saddened by the news that Sally Ride passed away yesterday at the age of 61.  She lost her battle with pancreatic cancer, as almost everyone with the awful disease inevitably does.  This blog post represents a cathartic effort on my part to offer a note of thanks to the first US woman in space.

When the shuttle Challenger blasted off on its historic journey early in the summer of 1983, I was a few months shy of 13 and living in South Charleston, West Virginia.  I had just finished 7th grade, which was my first year in junior high school.  Moses Malone, Dr. J and the rest of the Philadelphia 76ers had swept the Los Angeles Lakers in the NBA Finals a month before Sally Ride's famous ride, but I was too obsessed with playing and watching baseball to have paid basketball much attention.  Tony LaRussa had the White Sox from the south side of Chicago winning left and right; Cal Ripken, Jr was having a stupendous sophomore season; the "Wheeze Kids" in Philadelphia were having fun with my former Reds' heroes Pete Rose, Joe Morgan, and Tony Pérez.  Besides baseball, I loved reading and doing math.  I was a sports nerd -- and remain one to this day.  Politics and science also interested me, which really meant that I was a sports NERD.  A kid like me playing baseball all the time on his summer vacation still took the time to follow the news of Sally Ride's trip into space.

As a near teenager who had no idea what he was going to do with his life beyond a hope of playing professional baseball, my mind was ripe for learning, and Sally Ride taught me something in that summer of 1983.  Though much societal progress for women had been made by that time, many stereotypes were still floating about.  Many in my family fit some of those stereotypes, like men working and women staying home.  I saw mostly male doctors and female nurses.  Women dominated jobs like secretaries, elementary school teachers, stewardesses, librarians, waitresses, and bank tellers.  Pilots and scientists, however, seemed to my naïve mind to be jobs for men.  Jobs were not nearly as gender segregated in 1983 as they were in past decades, but perceptions then were much different compared to what they are in today's world.

What did I see in Sally Ride?  The first thing I remember seeing was a woman astronaut.  I fully admit that that sight was weird for me.  Sally Ride surely inspired a countless number of girls by showing them what's possible.  Pictures of Sally Ride working on the Challenger while it orbited Earth also showed me what's possible.  She not only changed the zeitgeist with her flight, she raised the consciousness of the person writing these words.  She helped enlighten and educate me with evidence that women can be astronauts, and good ones, too.

The second thing I remember seeing was a woman scientist, and a physicist to boot.  As far was women in science, I knew of Marie Curie, but that might have been the extent of my list.  Not only was I watching a woman astronaut, I was watching a woman who had earned a PhD in physics, a field I didn't know that much about at the time, but knew that it was a "hard" science.  I can honestly convey now what I thought then:  Sally Ride was cool.

Though I never had the honor of meeting her, the impression Sally Ride made on me 29 years ago was as strong as if I had met her.  I took interest when a career move of hers made the news, and I was more in tune to women in science.  Beginning a decade ago, I devote part of the first class I teach in my introductory physics course to introducing my students to some of the influential physicists in history.  Sally Ride is part of that introduction, but I sneak her in as a goofy "quiz" question.  On a single slide, I show two photos.  For an example of how this goes, click here for mystery person A and here for mystery person B.  I then ask my class to identify each person.  Of course, I learn nothing new when I give this little "quiz."  Almost everyone knows that person B is Paris Hilton, and nobody (with the exception of one or two people in ten years) knows person A, even though Sally Ride dons a NASA shirt in the photo.  The point of my "quiz" is not to embarrass my students or to poke fun at Paris Hilton.  The point is to let my students know that as they embark on their study of physics, women are just as capable as men of becoming physicists, and many women have made great contributions to what we know in physics.  I want my students to know, too, that it is time they start acquainting themselves with women who have made serious, important, and lasting contributions to the human species, and not just with those who dominate pop culture headlines for superficial (at best) contributions.

I'm sure that Sally Ride's life will continue to enlighten people as they learn about her.  Articles about her death revealed that Sally Ride was a lesbian.  I hope that that fact is part of people's enlightenment.  Sally Ride showed that the ability and talent needed to earn a PhD in physics and become an astronaut have absolutely nothing whatsoever to do with gender and sexual orientation.

Thank you, Sally Ride, for the indelible impression you made on me nearly three decades ago.

23 July 2012

Tour de France Summary

Another Tour de France is in the books, and Great Britain has its first champion.  Below is a table that summarizes the stages' winning times and our predictions.

Stage Actual Predicted Difference % Diff.
0 0h 07' 13" 0h 07' 35" 00' 22" 5.08
1 4h 58' 19" 4h 49' 18" -09' 01" -3.02
2 4h 56' 59" 4h 48' 45" -08' 14" -2.77
3 4h 42' 58" 4h 47' 16" 04' 18" 1.52
4 5h 18' 32" 5h 10' 00" -08' 32" -2.68
5 4h 41' 30" 4h 35' 16" -06' 14" -2.21
6 4h 37' 00" 4h 57' 12" 20' 12" 7.29
7 4h 58' 35" 5h 13' 07" 14' 32" 4.87
8 3h 56' 10" 3h 57' 04" 00' 54" 0.38
9 0h 51' 24" 0h 51' 06" -00' 18" -0.58
10 4h 46' 26" 5h 09' 49" 23' 23" 8.16
11 4h 43' 54" 4h 28' 03" -15' 51" -5.58
12 5h 42' 46" 5h 40' 12" -02' 34" -0.75
13 4h 57' 59" 5h 02' 23" 04' 24" 1.48
14 4h 50' 29" 5h 03' 27" 12' 58" 4.46
15 3h 40' 15" 3h 50' 46" 10' 31" 4.77
16 5h 35' 02" 5h 34' 01" -01' 01" -0.30
17 4h 12' 11" 4h 01' 29" -10' 42" -4.24
18 4h 54' 12" 5h 15' 05" 20' 53" 7.10
19 1h 04' 13" 1h 04' 39" 00' 26" 0.67
20 3h 08' 07" 3h 05' 49" -02' 18" -1.22
TOTAL 86h 44' 14" 87h 32' 22" 48' 08" 0.92
We predicted five stages to better than 1%, eight stages to better than 1.5% (rounded), and 12 stages to better than 3% (rounded).  I am very pleased with our predictions!  I would obviously liked to have done better on Stages 6, 10, and 18.  My student, Brian Ramsey, and I will sit down this week and go through the Tour de France again and see if can discover how to have modeled the race even better.  The point of all this from a research point of view is to better understand how to model the real world.  When one of our predictions matches an actual time to better than 1%, we think we have a good idea what's going on.  When we are off by more than 7% or so, we need to let the real world teach us how to do better.

Note the last row in the above table gives the sum of the stage-winning times.  Our model cyclist completed the Tour de France in a time 0.92% slower than the sum of all the stage-winning times.  Note that that time is not the total time posted by this year's winner, Bradley Wiggins.  His winning time was 87h 34' 47".  Though that time is a mere 02' 25" seconds off from the sum of our stage-winning times, our goal at the outset was not to predict the overall time for any one cyclist, but the sum of the stage-winning times.  My model could, in fact, be better at predicting the winner's overall time than the sum of stage-winning times.  I use published research to determine power outputs, and I don't use maximum values unless there is a particularly steep climb that must be overcome.  Athletes are getting better every year, and it's clear to me over the past two years that I need to up power outputs on certain portions of stages.  Again, there is more for us to learn, which is what makes all this so much fun!

For anyone wishing for more details on my model, check out Chapter 4 of my book.  Click here for the Amazon link.  Click here for a paper I gave at the most recent ISEA conference in Lowell, Massachusetts.  It describes my 2011 Tour de France work.

22 July 2012

Great Tour de France Finish!

My suggestion yesterday that Mark Cavendish would help give Team Sky a wonderful day just came to fruition.  As he did last year and the two years before that, the Manx Missile won the final stage of the Tour de France.  Below is the comparison between his time and our prediction.
  • Stage 20:  3h 08' 07" (actual), 3h 05' 49" (prediction), 02' 34" fast (-1.22%)
Given how difficult it is to model the final stage of the Tour de France, I am extremely pleased with our prediction.  Cavendish's average speed is given below.
  • Stage 20:  10.63 m/s (38.27 km/hr or 23.78 mph)
It was a foregone conclusion at the start of today's stage that Bradley Wiggins of Great Britain would win this year's Tour de France.  Wiggins claimed victory with an overall time of 87h 34' 47", 03' 21" ahead of Team Sky mate Chris Froome.  A total of our predicted times gives 87h 32' 22", just 02' 25" faster than Wiggins' time, or -0.046% off.

Because we were after each stage's winner, it is better to sum the stage-winning times.  The sum of all stage-winning times is 86h 44' 14", which means we were 48' 08" slower than that time, which amounts to an error of 0.92%.  On the surface, we did a much better job determining the overall winner's time than we did the sum of stage-winning times.  The power outputs we used appear to represent an individual athlete's performance instead of the collective performances of the top athlete in each stage.

I will write a summary post for this year's Tour de France sometime tomorrow.  For now, set science aside and marvel at the wonderful feat Bradley Wiggins just completed.  As if Great Britain didn't already have enough to celebrate in the sports world right now!

On the US side, I note the wonderful effort of Tejay van Garderen, who finished 5th at 11' 04" behind Wiggins.  The soon-to-be 24-year-old easily won the white jersey as the top youth cyclist in this year's race.  Well done!

21 July 2012

26 Seconds Off Wiggins' Time!

Seeing Bradley Wiggins come in as the final finisher in today's Stage 19 individual time trial made my day!  He was so fast, and he brought the winning time down to the point that we almost nailed it perfectly.  Below is the comparison between Wiggins and us.
  • Stage 19:  1h 04' 13" (actual), 1h 04' 39", 26" slow (0.67% error)
Wiggins won his second stage, both of which have been individual time trials, and all but sealed up his Tour de France win today.  Check out his average speed.
  • Stage 19:  13.89 m/s (49.99 km/hr or 31.06 mph)
Wow, that's fast!

Tomorrow's final stage is 120.0 km (74.56 miles) long and takes riders from the commune of Rambouillet to the famed Avenue des Champs-Élysées in Paris.  The final Tour de France stage has always been a challenge for us to model because it is mostly ceremonial.  Watch for Wiggins sneaking a sip of champagne while cycling!  We nearly nailed the time Mark Cavendish had in winning last year's final stage.  We hope to have estimated well just how much to reduce cyclist power output in our model.  Below is our prediction.
  • Stage 20:  3h 05' 49" (prediction)
Will Cavendish win the final stage again and give Team Sky an all-around wonderful day?  Enjoy your ride into Paris, Bradley Wiggins!

20 July 2012

Manx Missile Blasts Stage 18!

Mark Cavendish won his second long flat stage of this year's Tour de France.  We were once again too slow with our prediction.  Cavendish and the other cyclists who finished just inside five hours surprised us!  Below is the comparison with our prediction.
  • Stage 18:  4h 54' 12" (actual), 5h 15' 05" (prediction), 20' 53" slow (7.10% error)
The is our second-to-worst prediction (Stage 10 at 8.16% error is our worst).  We were once again stunned by how much power the top cyclists were outputting.  Below is what Cavendish averaged for today's stage.
  • Stage 18:  12.60 m/s (45.38 km/hr or 28.20 mph)
Cavendish won Stage 2 with an average speed of 11.64 m/s (8.25% faster today), and Stage 2 was 15.0 km (9.32 miles) shorter!  Plus, Stage 2 was was essentially flat, whereas Stage 18 contained three category 4 climbs and one category 3 climb.  To match Cavendish's time today, we would have needed 15% - 20% additional power in our model.  Suffice to say, we are quite impressed with what the Manx Missile did today!

Tomorrow's Stage 19 is the penultimate stage of this year's Tour de France.  It is an individual time trial that runs over 53.5 km (33.2 miles) from Bonneval to Chartres, taking riders north and closer to Paris.  Below is our prediction.
  • Stage 19:  1h 04' 39" (prediction)
Given how fast cyclists were today, we won't be shocked if someone sneaks under an hour.

19 July 2012

Valverde Takes Final Mountain Stage!

Alejandro Valverde of Spain won the last mountain stage in this year's Tour de France with an impressive final climb to cross the finish line all by himself.  Christopher Froome and Bradley Wiggins were just 19 seconds behind, which may just lock up this year's race for Wiggins.  Below is the comparison between our prediction and Valverde's winning time.
  • Stage 17:  4h 12' 11" (actual), 4h 01' 29" (prediction), 10' 42" fast (-4.24% error)
I challenged riders yesterday to finish in under four hours, but the final climbs were just too brutal and we were a little more than 4% too fast.  I don't mind the size of the error too much; what's mainly important for me is learning how to better model stages like today's grueling mountain stage.  Below is Valverde's average speed.
  • Stage 17:  9.484 m/s (34.14 km/hr or 21.21 mph)
It was slower than I thought, but still quite impressive for such a challenging stage.

Tomorrow's 222.5-km (138.3-mile) flat Stage 18 takes riders almost due north from the commune of Blagnac to the commune of Brive-la-Gaillarde.  There are three category 4 climbs and one category 3 climb.  Below is our prediction.
  • Stage 18:  5h 15' 05" (prediction)
Bradley Wiggins, Christopher Froome, and Team Sky look too strong this year.

18 July 2012

High-Jump Physics

The current issue of Outside magazine has a story on Jesse Williams, a US high-jumper who is one of the favorites in the upcoming London Olympics.  Shorter than most of his competition, Williams is able to make up for his lack of height with some great training and helpful physics.  I contributed physics ideas to the story.  Click here for the story.

Note that the liftoff force I give at the end of the article is an estimate of the average force, not the maximum instantaneous force.

I'll be rooting for Jesse Williams to take home the gold!

61 Seconds Off Stage 16!

Thomas Voeckler of France was all alone crossing the finish line to win today's Stage 16 of the Tour de France.  It was Voeckler's second stage win; both have been mountain stages.  When Voeckler broke free at the end, I knew we were in for a great prediction.  Below is the comparison between Vockler's winning time and our prediction.
  • Stage 16:  5h 35' 02" (actual), 5h 34' 01" (prediction), 01' 01" fast (-0.30% error)
Voeckler is clearly one of the world's best mountain cyclists.  Check out his average speed below.
  • Stage 16:  9.80 m/s (35.38 km/hr or 21.92 mph)
Ponder for a moment just how impressive that average speed is.  Two category 1 climbs and two climbs that are beyond categorization over a total distance of 197.0 km (122.4 miles) -- and Voeckler averaged 9.80 m/s.  Impressive!

Tomorrow's Stage 17 is the final mountain stage and picks up where Stage 16 left off, in the spa town of Bagnères-de-Luchon.  Besides having to negotiate category 1, 2, and 3 climbs before reaching an hors catégorie climb, cyclists will have to finish the stage with a category 1 climb.  The 143.5-km (89.17-mile) stage ends in the ski resort at Peyragudes -- a great ride in the Pyrenees!  Below is our prediction.
  • Stage 17:  4h 01' 29" (prediction)
Will tomorrow's winner be able to sneak under four hours?  Bradley Wiggins continues to look strong while holding onto the yellow jersey.  If someone wants to make a move on him, it had better be tomorrow!

17 July 2012

Tour de France Stage 16 Prediction

Tomorrow's Stage 16 looks to be a grueling mountain stage.  There are two climbs with the classification hors catégorie; two others are category 1 climbs.  Instead of describing the stage in any more detail here, I invite you to examine the stage profile for yourself.  Click here to get to the Tour de France website's Stage 16 page.  You may examine the "Stage profile" and the "Mountain passes & hills" images to see just how tough tomorrow's stage really is.  Below is our prediction.
  • Stage 16:  5h 34' 01" (prediction)
Based on how the athletes have impressed me to this point, I won't be surprised if we are too slow.  It should be fun in the Pyrenees tomorrow!

16 July 2012

Fedrigo Wins Stage 15!

Pierrick Fedrigo of France won Stage 15 of this year's Tour de France with a fantastic sprint at the end to edge German cyclist Vande Velde Christian by just two seconds.  Fedrigo is the 4th Frenchman to win a Tour de France stage this year.  Below is the comparison between Fedrigo's time and our prediction.
  • Stage 15:  3h 40' 15" (actual), 3h 50' 46" (prediction), 10' 31" slow (4.77% error)
The same thing that happened yesterday that happened today.  A group of cyclists led by German André Greipel, who earned 7th place, came in 11' 50" behind Fedrigo.  Once again, our prediction was better suited for the second group finishing than for the dominant sprinter that won the stage.  I don't mind the error under 5%, but it's clear that we have ever-so-slightly underestimated the power output of the dominant sprinter in the last two stages.  Below is Fedrigo's average speed.
  • Stage 15:  11.99 m/s (43.18 km/hr or 26.83 mph)
Tomorrow is a rest day and cyclists will need it in preparation for the two great mountain stages awaiting them after their day off.  Our prediction for Stage 16 will be posted within the next 24 hours.

15 July 2012

More Tour de France Greatness!

Luis León Sánchez of Spain did what I thought might happen -- win Stage 14 of this year's Tour de France in under five hours.  What a finish he had!  As I noted yesterday, I'll never cease being impressed by what the world's best do on a bicycle.  Below is the comparison between the winning time and our prediction.
  • Stage 14:  4h 50' 29" (actual), 5h 03' 27" (prediction), 12' 58" slow (4.46% error)
Our error isn't too bad, but think about how great Sánchez was today.  How did yellow-jersey donning Bradley Wiggins do?  He came in 15th with a time of 5h 08' 44".  What about last year's winner, Cadel Evens?  He was right behind Wiggins in 16th place with the same time.  Our prediction would have only been 1.71% off had Evens or Wiggins won the stage, but that's not what we try to do.  Our goal is to predict the winning time; our true error was 4.46%.  It should be clear just how dominant Sánchez was today.  His average speed is below.
  • Stage 14:  10.96 m/s (39.45 km/hr or 24.51 mph)
That's a great average speed for such a tough mountain stage.

Tomorrow's stage is classified as flat, but there are a couple of category 4 climbs and one category 3 climb.  Riders begin the 158.5-km (98.49-mile) stage in the commune of Samatan and head west to the commune of Pau, which is just north of the Pyrenees.  Below is our prediction.
  • Stage 15:  3h 50' 46" (prediction)
After tomorrow's stage, cyclists take a day of rest on Tuesday, 17 July.  They then leave Pau the following day for two great mountain stages.

14 July 2012

Interview on All Around Sports

John Ingoldsby interviewed me for All Around Sports while I was in Lowell, Massachusetts for the international sports engineering conference I've described in recent posts.  The interview aired on Friday, 13 July 2012.  Click here to access the interview.  You can listen to John Brenkus of ESPN's Sports Science being interview first.  My interview begins around 13:46 and ends roughly at 19:18 (you may believe the interview ends a minute or so before then, but keep listening!).

Greipel Takes Stage 13 in Under 5 Hours!

André Greipel won his third flat stage of this year's Tour de France with an impressive win in Stage 13 today.  The German cyclist satisfied my curiosity by taking today's stage in under five hours.  Below is the comparison between Greipel's time and our prediction.
  • Stage 13:  4h 57' 59" (actual), 5h 02' 23" (prediction), 04' 24" slow (1.48% error)
I am very pleased with our prediction, and I am quite impressed to see the world's best take a stage like today's in under five hours.  Well done, Herr Greipel!  His average speed is given below.
  • Stage 13:  12.14 m/s (43.69 km/hr or 27.15 mph)
Tomorrow's Stage 14 takes riders into the Pyrenees.  They begin the 191.0-km (118.7-mile) mountain stage in the commune of Limoux and finish up in the commune of Foix.  A taxing category 2 climb early in the stage will whet our appetites for the two monster category 1 climbs later in the stage.  The first has riders ascend Port de Lers, which has an elevation of 1517 m (4977 feet).  Just 26 km (16 miles) from that peak is Mur de Péguère at an elevation of 1375 m (4511 feet).  Below is our prediction.
  • Stage 14:  5h 03' 27" (prediction)
I will once again be anxious to see if tomorrow's winner will finish the stage in under five hours.  These great athletes never cease to impress me, so I won't be surprised to see a "4" in front of the winning time.  Bradley Wiggins looked strong today and maintains the yellow jersey.  If someone is to take that yellow jersey from Wiggins, that person will need to shine in Pyrenees!

13 July 2012

ISEA Conference Ends

I write this post while sitting in the Logan Airport in Boston.  Note to Logan:  there is no reason to charge for internet use!  I could use it for free on the train from Lowell to Boston.  Nothing like gouging a captive audience!

The last day of the ISEA conference began with a talk by Wolfram Meyer of FIFA who discussed FIFA's quality control standards.  I then attended another session on "Aerodynamics of Sports Projectiles" where I learned more about flight dynamics associated with cricket balls and golf balls.  A couple of additional talks on swimming and football pitches wrapped up the presentations I saw.  A closing ceremony set the stage for ISEA's next conference in 2014, which will be held in Sheffield, UK.  Having lived in Sheffield for more than ten months during my sabbatical year in 2008-09, I'm hoping to return in a couple of years so that I may attend the next ISEA conference.  I certainly enjoyed this one!

It has been brought to my attention that the slides from my keynote address are now available online.  Click here for a link to my presentation.

Much Better on Stage 12!

The Brits continue to dominate this year's Tour de France.  David Millar of Scotland won today's long Stage 12.  Below is the comparison of Millar's time with our prediction.
  • Stage 12:  5h 42' 46" (actual), 5h 40' 12" (prediction), 02' 34" fast (-0.75% error)
I'll definitely take another stage prediction under 1%!  Below is Millar's average speed.
  • Stage 12:  10.99 m/s (39.56 km/hr or 24.58 mph)
Tomorrow's flat Stage 13 begins in Saint-Paul-Trois-Châteaux in southeastern France and ends in the seaside town of Cap d'Agde after 217.0 km (134.8 miles) of cycling.  Below is our prediction.
  • Stage 13:  5h 02' 23" (prediction)
I am anxious to see if the world's best can complete Stage 13 in under five hours.  Wiggins and Froome of Team Sky continue to hold the top two overall spots.  Will there be a great sprint to end tomorrow's stage?

12 July 2012

More Fun at the ISEA Conference

Today was really fun for me at the 9th Conference of the International Sports Engineering Association (ISEA).  The conference began activities today with a keynote address from the person writing this blog post.  I enjoyed giving that speech as much as any talk I've ever given.  I built on some of my earlier blog posts about the conference and noted how special it is that we all see the world in different ways.  The engineers at this conference have taught me new ways to think about problems and new ways to attack those problems.  I hope I've been able to shed a little light on how a physicist sees the world.  My keynote address this morning gave the audience a brief look at how I, as a physicist, view some of the events at the upcoming Olympics in London.  I ended my talk by urging those in the audience to get into elementary schools at least once a year and show kids how great it is to be a scientist or engineer (whichever label fits better!) using sports as the vehicle.  Following my talk, several audience members shared their efforts to reach out to kids.  There are some very creative people out there trying to get kids interested in science.  As I note on the first page of my book, children make the best scientists.  They do, however, couple insatiable curiosity with a great deal of credulity.  Learning to do science well means learning to ask questions, and require data and evidence to support answers.  We don't want to tell kids what to think; we want to help them learn how to think.

The first session of talks I heard was titled "Aerodynamics of Sports Projectiles."  I saw great talks on shuttlecocks, knuckleballs, and soccer ball surfaces.  Because three talks run simultaneously, I missed (and have missed) several talks I wanted to see.  I did have to miss the fourth session talk so that I could hear my former office mate at Sheffield, James Clarke, talk about his work on shoe-surface interactions in tennis.

After a session on "Protective Equipment," I moved on to the session "Aerodynamics of Sports Projectiles" (again!), which was chaired by my friend and colleague, Alan Nathan, who I got to know well at last year's summer meeting of the American Association of Physics Teachers, where we were both invited to give sports talks.  Alan has done a lot of great work over the years on baseball physics.  Anyway, I heard fascinating talks on shuttlecocks, Doppler radar to track sports balls (indirectly, it turns out), and non-rotating soccer balls.  My own soccer aerodynamics talk was the fourth and last of the session.  I was flattered by the good turnout and the many questions I was asked following my talk.

After another session on "Aerodynamics of Sports Projectiles," I attended the poster session.  There are so many wonderful research areas, from new baseball bats to the weathering of American football helmets.  In summary, a great day at the conference!

I was, unfortunately, unable to attend the evening banquet at a nearby farm.  I've had to miss out on all the evening entertainment here in Lowell because I've got a herniated disc in my back.  I've been able to fake walking upright during the day, but I can't fake it much past 5:00 pm.  It's bad timing to have a back issue right now, but I look on the bright side and reflect on how much I've learned and how many great researchers I've met from all over the world.  I'm glad I'm here!

Click here for an article that quotes me as I talk about the conference.

Another Stage Win for France!

Pierre Rolland won today's grueling Stage 11.  Below is the comparison with our prediction.
  • Stage 11:  4h 43' 54" (actual), 4h 28' 03" (prediction), 15' 51" fast (-5.58% error)
There was a crash in today's stage on a descent that involved Rolland.  Though it surely did not slow him by 16 minutes, our prediction looks a little better in light of the crash.  I'm happy that we are closer today compared to yesterday's prediction.  We were slow then, fast now.  Predicting stage-winning times for the Tour de France is challenging!  Below is Rolland's average speed.
  • Stage 11:  8.689 m/s (31.28 km/hr or 19.44 mph)
Those brutal climbs certainly bring the average speed down!

Tomorrow's Stage 12 is the longest stage at 226.0 km (140.4 miles).  The medium-mountain stage begins in the commune of Saint-Jean-de-Maurienne and takes cyclists west to Annonay/Davézieu.  Riders have to traverse two category 1 climbs early on before a relatively long downhill stretch.  A category 3 climb awaits cyclists near the stage's end.  Below is our prediction.
  • Stage 12:  5h 40' 12" (prediction)
Bradley Wiggins maintains the yellow jersey and Chris Froome is just over two minutes back in second place.  Can anyone catch Team Sky?

11 July 2012

Another Great Day at ISEA Conference

I enjoyed another intellectually stimulating day here in Lowell, Massachusetts.  Bruce Jahnke gave an interesting keynote address in the morning that discussed new technologies in snow ski equipment that are being utilized at K2 Sports.  Rick Greenwald then spoke briefly about safety issues in skiing.

An hour-long panel session on sports engineering education in Europe was quite interesting.  We in the US can learn a great deal from what our European colleagues are doing to educate students interested in sports engineering and sports science.

I chaired a session called "Aerodynamics of Athletic Gear," which had six great talks.  I learned a lot about how cycling aerodynamics is studied and how researchers are developing new technologies to improve fabrics worn by athletes.  This latter work is important as athletes compete in events like speed skating where the difference between winning and losing can be thousandths of a second.

A session on "Modeling & Simulation" rounded out my day.  Computational techniques have come a long way in the past couple of decades and it is fascinating to see what people are doing with finite-element analysis and computational fluid dynamics.

Besides the interesting perspectives I am getting from interacting with engineers (see my post from yesterday), I am enjoying interacting with people from all over the world.  No matter where we come from, though, we are all interested in a better understanding of the natural world.  We all speak the universal language of science!

Voeckler Takes Stage 10!

The world's top athletes never cease to amaze me.  Just when I start to worry that my model does not have enough power for climbing a monster ascent, the world's best astonish me.  Thomas Voeckler won Stage 10 today with an impressive ride.  Below is the comparison with our prediction.
  • Stage 10:  4h 46' 26" (actual), 5h 09' 49" (prediction), 23' 23" slow (8.16% error)
My hat's off to those elite cyclists!  Below is Voeckler's average speed.
  • Stage 10:  11.32 m/s (40.72 km/hr or 25.32 mph)
That's better than the average speeds for the winners of Stages 1, 4, 7, and 8.  Impressive!

Tomorrow's Stage 11 begins in the commune of Albertville and ends 148 km (91.96 miles) later in La Toussuire/Les Sybelles in the French Alps.  Two climbs of the hors catégorie variety plus a category 1 climb and a category 2 climb await cyclists tomorrow.  Below is our prediction.
  • Stage 11:  4h 28' 03" (prediction)
After today's stage, I hope we are not too slow!  Bradley Wiggins, holder of the yellow jersey, Thomas Voeckler, and the other Tour de France competitors are impressive to behold!  They should enjoy the vistas in the French Alps tomorrow.

10 July 2012

First Full Day at ISEA Conference

This is the first time I've attended a conference of the International Sports Engineering Association (ISEA) -- and I love it!  Lowell, Massachusetts is a wonderful setting for the conference; Patrick Drane and James Sherwood have done an excellent job organizing everything.

John Brenkus of ESPN's Sports Science started off today's activities with a phenomenal keynote address.  He is a dynamic speaker with lots of entertaining videos of athletes as subjects of experiments.

The three sessions I attended today were "Modeling & Simulation,"  "Aerodynamics of Sport Projectiles," and "Biomechanics."  My Tour de France talk was part of the first session.  I learned a lot about what's being done with cycling, cricket, tennis, baseball, softball, discus, American footballs, and soccer balls.  Many bright people are here to share their research; I'm glad to have been able to speak to a dozen or so of them at great length today about their work.  Their passion is contagious!

This ISEA conference is the first engineering conference I've attended.  I can see numerous differences between an engineering conference and the many physics conferences that I've attended.  Engineers and physicists have different ways of looking at problems.  They ask different questions and approach solutions in different ways.  Experiencing the differences is what makes this conference so much fun for me.  We all see the world in unique ways, and engineers have taught me new ways to think about problems.  I've even had to get used to different language that's used to express ideas.  Even more than what experimental physicists have to offer, engineers tackle problems in very practical ways without as much concern for underlying fundamentals.  This refreshing way of thinking helps me understand my own research better.  I find myself being drawn to the physics that forms the foundation of what the engineers study, but they have taught me that thinking about the elemental structure may not always be the best approach.  They have also shown me some phenomenal technology they employ to study surfaces, trajectories, and other aspects of sports.

I can hardly wait for tomorrow!

Tour de France Stage 10 Prediction

Tomorrow's Stage 10 begins in the commune of Mâcon and ends after 194.5 km (120.9 miles) of cycling in the commune of Bellegarde-sur-Valserine, which is just west of the Swiss border.  Predicting Stage 10 is a challenge because of what the French refer to as hors catégorie, which is the designation given to a climb that is "beyond categorization."  Stage 10 has such a climb.

When cyclists reach the French commune of Béon, they will have biked for 130.5 km (81.09 miles) and be at an elevation of 255 m (837 feet).  Today's day of rest will come in handy because they will then need to ascend to Col du Grand Colombier, which is at an elevation of 1501 m (4925 feet).  That 1246 m (4088 feet) change in elevation happens after just 21.0 km (13.0 miles) of cycling.  That's quite a climb!  Drawing a right triangle with a hypotenuse of 21.0 km and a vertical side of 1.246 km gives an angle of 3.4 degrees opposite that 1.246-km side.  That works great as an average, but cyclists won't traverse the average.  They must traverse the final 17.4 km (10.8 miles) of that 21.0 km on a 7.1% climb.

Upon reaching the peak of Col du Grand Colombier, cyclists will still have 43.0 km (26.7 miles) left, including a Category 3 climb in the middle of that stretch.  To state the obvious, Stage 10 will be quite a challenge for this year's Tour de France competitors.  Below is our prediction.
  • Stage 10:  5h 09' 49" (prediction)
The challenge for us as we predict a stage with such a brutal climb is determining what power cyclists will be able to output during their ascent.  If the climb proves to be too intense, our prediction will be too fast.  We want to see the world's best dominate Col du Grand Colombier!

09 July 2012

Stage 9 to Wiggins -- We're 18 Seconds Off!

Bradley Wiggins won today's Stage 9, which was an individual time trial.  We just about nailed it!  Below is the comparison between Wiggins and us.
  • Stage 9:  0h 51' 24" (actual), 0h 51' 06" (prediction), 18" fast (-0.58% error)
I missed watching the stage because I was traveling this morning.  I am attending International Sports Engineering Association's 9th International Sports Engineering Conference in Lowell, Massachusetts.  Click here for the conference webpage and here for a brief article on the conference.  When I got to my hotel room, I quickly set up my computer and checked to see how Stage 9 came out.  I was quite pleased to see Wiggins' winning time!  Below is his average speed.
  • Stage 9:  13.46 m/s (48.44 km/hr or 30.10 mph)
Now that's fast!  Wiggins retains the yellow jersey after his win today, extending his lead in the overall standings to 01' 53" over Cadel Evans.  Wiggins' Team Sky mate Chris Froome is third at 02' 07" behind Wiggins.

Tomorrow is the first of two rest days for this year's Tour de France.  A couple of great mountain stages await cyclists on Wednesday and Thursday.  They better get plenty of rest tomorrow!  I will post a prediction for Stage 10 either tonight or tomorrow.

Because I am in such a wonderful sports science environment this week, I will write a few blog posts that deal with my time at the conference.  Besides giving three talks myself, I will attend as many talks as I can and learn as much as possible before I have to leave on Friday.  It's going to be a great week!

08 July 2012

54 Seconds Off Pinot's Stage 8 Win!

Home-country favorite Thibaut Pinot won today's Stage 8 with an impressive sprint at the end to beat Cadel Evans by 26 seconds.  Below is the comparison with our prediction.
  • Stage 8:  3h 56' 10" (actual), 3h 57' 04" (prediction), 54" slow (0.38% error)
I am quite happy with today's result!  We had just the right amount of cyclist power for today's stage.  Pinot's average speed is given below.
  • Stage 8:  11.11 m/s (40.01 km/hr or 24.86 mph)
That is almost exactly the same average speed that Chris Froome had yesterday (Pinot was actually about 0.063% faster).

Tomorrow's Stage 9 is a 41.5-km (25.8-mile) individual time trial that begins in the commune of Arc-et-Senans and ends in the city of Besançon.  Cyclists will be on the edge of the Jura Mountains, meaning that the time trial won't be all flat.  Below is our prediction.
  • Stage 9:  0h 51' 06" (prediction)
We think the time trial will be won in under an hour.  Bradley Wiggins still has the yellow jersey with a 10-second lead over last year's winner, Cadel Evans.  Will there be a shakeup of the overall standings after tomorrow's time trial?

07 July 2012

Great Day for Team Sky!

Brit Chris Froome dominated the final climb today to win Stage 7 of the Tour de France.  He bettered last year's winner, Cadel Evens of Australia, on the last, grueling uphill toward the finish line.  Below is the comparison with our prediction.
  • Stage 7:  4h 58' 35" (actual), 5h 13' 07" (prediction), 14' 32" slow (4.87% error)
Our error is lower than yesterday's, but I still remain amazed by how well cyclists have done over the past two days.  Their power outputs have exceeded what we've used in our model.  Don't let it slip your mind as you watch these cyclists that you are watching the best of the best.  There is no way I could have looked respectable on my bike on Stage 7's final climb!

Froome's average speed is given below.
  • Stage 7:  11.11 m/s (39.99 km/hr or 24.85 mph)
Bradley Wiggins, Froom'e Team Sky teammate and fellow Brit, now has the yellow jersey.

Tomorrow's medium-mountain Stage 8 begins in the city of Belfort and takes cyclists 157.5 km (97.87 miles) southeast to the Swiss town of Porrentruy.  There are lots of great climbs in the Jura Mountains in this stage (click here to see the profile on the Tour de France website).  The stage ends on rather flat terrain, so look for a great sprint to finish things off.  Below is our prediction.
  • Stage 8:  3h 57' 04" (prediction)
Based on how cyclists have done so far, I think the winner can cross the finish line in under four hours.  Will Team Sky keep the yellow jersey?

06 July 2012

Sagan Wins Stage 6!

Peter Sagan of Slovakia won his third stage of this year's Tour de France with a performance faster than we predicted. Below are the results.
  • Stage 6:  4h 37' 00" (actual), 4h 57' 12" (prediction), 20' 12" slow (7.29% error)
I usually don't mind having errors under 8%, but I was surprised how fast this stage turned out to be.  Check out Sagan's average speed below.
  • Stage 6:  12.49 m/s (44.95 km/hr or 27.93 mph)
Excluding the average speed of the individual time trial that was the Prologue, the above average speed for the winner of Stage 6 is the greatest so far.  Sagan's average speed was 7.2% greater than what Mark Cavendish had in winning Stage 2, a stage that was the same length as today's Stage 6.  Those cyclists are amazing athletes!

Tomorrow's Stage 7 is the first of two straight medium-mountain stages before Stage 9's individual time trial.  After that time trial, riders will enjoy their first of two rest days on Tuesday, 10 July.  Stage 7 begins in the commune of Tomblaine and takes riders 199.0 km (123.7 miles) southeast to the ski station at La Planche des Belles Filles in the Vosges Mountains.  Besides having a great climb during the middle of Stage 7, the stage ends with the climb to the ski station, which is at an elevation of 1035 m (3396 feet) above sea level.  Below is our prediction.
  • Stage 7:  5h 13' 07" (prediction)
Cyclists surprised us a little with today's speed.  Will they be able to surprise us tomorrow with a fast final climb?

05 July 2012

Two in a row for Greipel!

André Greipel won his second straight stage of this year's Tour de France with a great sprint at the end.  Another big crash just a few kilometers from the finish line played a role.  Peter Sagan, winner of Stages 1 and 3, was among those involved in the crash.  Below is the comparison of how our prediction matched the reality of Stage 5.
  • Stage 5:  4h 41' 30" (actual), 4h 35' 16" (prediction), 6' 14" fast (-2.21% error)
I'll certainly take that error!  Greipel's average speed is given below.
  • Stage 5:  11.63 m/s (41.88 km/hr or 26.02 mph)
Tomorrow's stage is mostly flat and stretches east 207.5 km (128.9 miles) from the northern French commune of Épernay to the city of Metz, which is not far from where France meets Luxembourg and Germany.  Our prediction for tomorrow's Stage 6 is given below.
  • Stage 6:  4h 57' 12" (prediction)
A couple of medium-mountain stages follow tomorrow's stage.  Fabian Cancellara still possesses the yellow jersey.  Let's hope there are no more big crashes tomorrow!

04 July 2012

Greipel Wins Stage 4!

German André Greipel just won Stage 4 of this year's Tour de France with a great sprint.  A huge crash happened a few kilometers from the finish line.  Below is a comparison of Greipel's winning time with our prediction.
  • Stage 4:  5h 18' 32" (actual), 5h 10' 00" (prediction), 8' 32" fast (-2.68% error)
Another prediction under 3% makes us happy!  Below is Greipel's average speed during his Stage 4 win.
  • Stage 4:  11.22 m/s (40.40 km/hr or 25.11 mph)
Tomorrow's flat Stage 5 picks up in Rouen and takes riders 196.5 km (122.1 miles) east to Saint-Quentin.  Below is our prediction.
  • Stage 5:  4h 35' 16" (prediction)
Fabian Cancellara, who escaped today's crash, maintains the yellow jersey.  Let's hope today's crash doesn't take anyone out of the race.  Mark Cavendish was involved in the crash, and tomorrow's Stage 5 is the kind of stage that Cavendish can win.

03 July 2012

Sagan Takes Stage 3!

Peter Sagan of Slovakia just won his second stage of this year's Tour de France.  Sagan sprinted away from his competition as he ascended the last Category 4 climb at the stage's end in Boulogne-sur-Mer.  A big crash near the end of Stage 3 did not involve Sagan.  Below is the actual result compared to our prediction.
  • Stage 3:  4h 42' 58" (actual), 4h 47' 16" (prediction), 4' 18" slow (1.52% error)
I can't complain about a 1.52% error!  Sagan's average speed is given below.
  • Stage 3:  11.60 m/s (41.77 km/hr or 25.96 mph)
Tomorrow's Stage 4 is a 214.5-km (133.3-mile) long flat stage, which begins in the commune of Abbeville and ends in the capital of Upper Normandy, Rouen.  Much like Stage 3, my student, Brian Ramsey, and I had to fill in some geographic data not seen on the Tour de France website's stage profile.  The model I describe in Chapter 4 of my book requires geographic data to create inclined planes of the terrain.  Some of the stage profiles for this year's race were in dire need of additional geographic information.  Our prediction for Stage 4 appears below.
  • Stage 4:  5h 10' 00" (prediction)
Will Fabian Cancellara hold the yellow jersey after tomorrow?  We shall see!

02 July 2012

Tour de France Update and Stage 3 Prediction

I thank my brother-in-law, Bob Calano, for putting my Tour de France predictions on my blog for me.  Below is a summary of how our predictions fared against the actual results.
  • Prologue:  7' 13" (actual), 7' 35" (prediction), 22" slow (5.08% error)
  • Stage 1:  4h 58' 19" (actual), 4h 49' 18" (prediction), 9' 01" fast (-3.02% error)
  • Stage 2:  4h 56' 59" (actual), 4h 48' 45" (prediction), 8' 14" fast (-2.77% error)
Fabian Cancellara of Switzerland won the Prologue; Peter Sagan of Slovakia won Stage 1; Mark Cavendish of Manx won Stage 2.  Below are their average speeds.
  • Prologue:  14.78 m/s (53.21 km/hr or 33.06 mph)
  • Stage 1:  11.06 m/s (39.82 km/hr or 24.75 mph)
  • Stage 2:  11.64 m/s (41.92 km/hr or 26.05 mph)
Part of the reason my student, Brian Ramsey, and I may have been a tad fast on the first couple of stages is that no cyclist really broke free of the peloton.  Several riders were awarded the same time in each of the past two stages.  We were hoping for some late breakaways!

I am pleased with how our predictions came out for the Prologue and first two stages.  Anytime the error is around 3% for a stage that takes nearly five hours to complete, I'm happy.

Tomorrow's Stage 3 is mostly flat for the first half of the stage.  Some lovely rolling hills make up the second half of the stage.  Classified as a "medium-mountain stage," the riders start from the French commune Orchies and end 197 km (122 miles) later in the city of Boulogne-sur-Mer, nearly at the English Channel.  Below is our prediction for tomorrow's Stage 3.
  • Stage 3:  4h 47' 16" (prediction)
Our predicted times for Stages 1, 2, and 3 are all quite similar.  Will we be a tad fast tomorrow?