New Men's Marathon Record!

Kenya's Wilson Kipsang Kiprotich won the Berlin Marathon in world-record breaking fashion.  He shaved 15 seconds off the record set almost exactly two years ago in the Berlin Marathon by fellow Kenyan, Patrick Makau Musyoki (click here for my 2011 post on that).  Kipsang's time of 2h 03' 23" for the 42.195-km (26 miles 385 yards) race meant an average speed of 20.519 kph (5.700 m/s or 12.750 mph).

Each day, we see progress in humanity's athleticism.  When will someone sneak under two hours in the marathon?  When I was born in 1970, the men's record was held by Ron Hill of the UK.  His time was 2h 09' 28.8".  Now 43 years later, the record is just 06' 05.8" less time.  To get below two hours, another 03' 23" needs to be shaved off the record.  How many years had to pass for 03' 23" to be shaved down to the current record?  A time of 2h 06' 46" would have been the record by four seconds when Ethiopian Belayneh Dinsamo ran 2h 06' 50" on 17 April 1988.  Dinsamo held the record for a little more than a decade.

It took just over a quarter century to knock an amount of time off the record that will have to be knocked off the current record to see a time under two hours.  Will we have to wait another quarter century???

Geno Smith and Quarterback Mechanics

About a fortnight back, I analyzed Geno Smith's three interceptions in a loss against the Patriots on Thursday, 12 September.  My work made it into a story in Metro New York, but I missed seeing it until today.  Smith has thrown two picks in each of the past two games, including today's loss at Tennessee.  To read my analysis, click here for the story by Kristian Dyer.

Soccer and Video Games

The FIFA 14 video game apparently had some bad aerodynamics in its coding.  I provided a little commentary in a recent Scientific American piece on this.  Click here for the article.  With air resistance, the shape of a kicked soccer ball's trajectory is not parabolic, which may come across that way in the article.  Anyway, it was nice to be contacted by Scientific American!

US "Heads" to World Cup in 2014!

With a 2-0 win over Mexico last night, the US soccer team secured a spot in the 2014 World Cup, which will be held in Brazil.  The best Team USA has fared in a World Cup was a third place finish way back in 1930.  I hope we'll do better next summer!

Our first goal in last night's match came on a beautiful corner kick by Landon Donovan.  Eddie Johnson provided the perfect header after the Mexican goal keeper found himself a bit out of position.  Check out the somewhat fuzzy video I found for Johnson's header (click on the image below for a larger view)

What really got me excited was Donovan's kick.  Looking down on the ball while in flight, one would have seen the ball spinning counterclockwise.  I tracked the ball in the video above and you can clearly see how the ball's spin helped it curve right into Johnson's location.  The Magnus force, which is due to the air being whipped asymmetrically off the back of the ball, is responsible for the curve.  Donovan served up a banana kick with whipped air!

RGIII Runs Through 1st Week of Sports Physics

Now just over a week into my first offering of Physics of Sports at Lynchburg College, I am finding that the course is more enjoyable than I had imagined (and I initially thought it was going to be loads of fun!).  At the end of the first class, I gave my students a brief survey to complete.  One of the questions asked them to list their three favorite athletes, who could be active, retired, or deceased.  One of the most popular choices was Robert Griffin III, known to most sports fans simply as RGIII (or RG3).  The dynamic young quarterback for the Washington Redskins took the NFL by storm after his Heisman-winning season at Baylor in 2011.

After an overview of dimensions and units conversions, we moved to one-dimensional motion.  London golds earned by Missy Franklin in the 200-m backstroke and Usain Bolt in the 100-m sprint made for good examples of approximately one-dimensional motion.  When it came time to analyze motion more carefully, however, I knew I had to use RGIII.  His 40-yard dash at the 2012 NFL Scouting Combine fit perfectly with what I wanted to do (click here for video of his sprint):  essentially one-dimensional motion using an athlete my students wanted to see.

The video I used was taken at 24 frames per second.  I went frame by frame and recorded RGIII's time at each yard marker.  The graph below is the result of that effort (click on the image for a larger view).

Each red data point is my best estimate of when RGIII's torso passed each yard marker (I converted yards to feet for the plot).  The blue curve is a best-fit function that helps smooth the way for time derivatives, such as RGIII's velocity, which I show below (click on the image for a larger view).

The video claims that RGIII completed the sprint in 4.38 s with a top speed of 24.6 mph (39.6 kph).  Given my admittedly rough estimations of where RGIII's torso was at each yard marker, all of which were angled from the camera view, I found that he completed the sprint in just over 4.37 s with a top speed of 23.2 mph (37.3 kph).  The NFL was certainly using more accurate timing devices, but I'm happy with how close I got.  RGIII's time and top speed are incredible!  Check out his acceleration below (click on the image for a larger view).

I have scaled his acceleration by the acceleration due to gravity.  Note that he explodes off the starting line with more than two g's!

When I began Physics of Sports, I was not planning to look at RGIII in the first week.  Letting students help decide what to cover in a sports physics course means that I get to learn things I wasn't expecting to learn.  RGIII certainly made for a fun first sporting example to analyze in detail.