Categories
Culture

Muybridge: Art, Motion and Biomechanics (repost 8/2010)

Edweard Muybridge visited the Corcoran Gallery of Art in 1887 to personally make a presentation of his eleven volume “Illustrations of Animal Locomotion”. They later purchased the text. An exhibition titled “Helios: Eadweard Muybridge in a Time of Change”  at the Corcoran displaying Muybridge’s groundbreaking photography and motion studies has just concluded. I had the joy of spending a few hours at the exhibit in close study. As an added and unrelated bonus I was also able to see a new exhibit on the artist Chuck Close.

Artists and scientists have long had an interest in human anatomy and motion. Over the last 50 years, movement and gait have been analyzed using gait plates, computer force distribution systems, electromyogram (EMG) and video. When, where and how did modern analytic methods develop? What was their antecedent? Most textbooks and articles are skimpy at best about much of the early history of the study of locomotion and movement.

The science of  biomechanics has forgotten about the 19th century developments that made for rapid progress in the last 100 years. The historical memories of biomechanics seem to start in the 20th century with Morton’s observations, and Elftman, Inman and Mann’s theories. Artists, however, remember Muybridge,  and going further back, it is clear that Michelangelo was deeply interested in anatomy and Leonardo (performed dissections and) wanted to know how everything worked. Along the way to the present, many other artists and scientists studied and observed animal and human movement. But until the late 19th century there was no technology available to capture data and information of movement.

Edweard Muybridge  (1830-1904) was the first to systematically develop equipment and techniques to photograph the movement of quadripedal and bipedal gait along with a variety of other movements, motions, and human athletic activities.  In 1877 Muybridge was hired by Leland Stanford to demonstrate that all 4 limbs were off the ground at one point during the trotting gait of a horse. Muybridge developed an automatically triggering electronic shutter. In 1878, Muybridge hooked up a series of about a dozen cameras to automatically and sequentially fire and record the gait of a horse.  While exposures at that time were often several minutes long, the 12 exposures occurred over about half a second.  A highly contrasting, light background was designed to enhance the image. A numbering system was used which gave positional and, indirectly, timing information. Stanford ultimately won his bet and was able to use Muybridge’s photographs to demonstrate that all of the horses feet left the ground during a trot.

Out of the studies of motion that Muybridge did came several breakthroughs that were noted by Rebecca Solnit in “River of Shadows”.

1)   An electronic automatically triggered shutter, which Muybridge felt would revolutionize photography.

2)   Advances in plates and development which could capture movement and allowed for capture of an image in less time than anyone had accomplished previously.

3)   Capturing of several images that could be mounted together to represent a cycle of motion (such as a gait cycle) rather than a single isolated moment.

4)   The possibility of sequencing and showing an image sequence as a moving picture to reanimate the movement as a moving picture.

The first and second breakthroughs were accomplished in 1877, the other breakthroughs came in 1878 and 1879. It took celluloid and other much later developments to bring a motion picture industry to life. But both the methodical study of movement and a film industry had their beginnings with the work of Muybridge.

Early technology was so bad that images were often barely discernable and had to be painted in. In some cases the images were filled in and then re-photographed by Muybridge. (The equivalent of photoshopping your work today.) Ultimately, however, Muybridge recorded many sequences of activity making up  about 11 volumes. The complete set of volumes was sold to the Corcoran museum in Washington, DC in the 1890’s for $600.

Stanford published a text on the movement of animals , while Muybridge was lecturing in England and employed by a professional society. Many images drawn after Muybridge’s plates and several of his images were used while the text gave Muybridge no credit for the work.

Muybridge’s work has often been discounted as merely “art”, but it was an important qualitative look at movement. Diagrams in modern texts detailing varieties of normal and abnormal gait look like they were sketched from his plates or photographed using methods similar to his. He influenced many artists, worked with Thomas Eakins and inspired Marcel Duchamp to paint “Nude Descending A Staircase“. Clearly there is inspiration, emotion, and art in his work, but using the scientific analysis and invention he was at the forefront in creating techniques that were later used to quantify motion and gait analysis. His text “Animals In Motion” has long been used by illustrators to draw sequences which when put together will stream as a moving animal. His work had great impact on animation and led to the development of film. Look for more details on Muybridge on my main website in the near future.

The Helios exhibit will next be seen at the Tate Britain in London from September 8, 2010 through January 16, 2011, and will finish at the San Francisco Museum of Modern Art from February 26 through June 7, 2011.

References:

River of Shadows: Eadweard Muybridge and the Technological Wild West. Penguin Books. 2003.

Helios: Eadweard Muybridge in a Time of Change. Philip Brookman. Corcoran Gallery of Art. 2010. (Exhibit and Catalog)

Picturing Time: The Work of Etienne Jules Marey. Marta Braun. University of Chicago Press: 1992.

Boxing - Muybridge Study
Boxing – Muybridge Study

Categories
Biology Culture Sports Medicine

Testosterone: Epitestosterone Ratio: Cheating or Genes?

(repost from 01/2011)

The Case Against Lance Armstrong” is the title of an article in the January 24, 2011 issue of Sports Illustrated. The case that is made within this article is based on in large part on what a few people with gripes against Lance have said. The other “hard” evidence is based on several tests detailing a very high Testosterone:Epitestosterone ratio. Before 2005 the tests normal was considered up to 6:1 and was then lowered to 4:1. Several tests over the years, which may have been Lance’s were considerably higher than this.

According to SI “Three results stand out: a 9.0-to-1 ratio from a sample collected on June 23, 1993; a 7.6-to-1 from July 7, 1994; and a 6.5-to-1 from June 4, 1996.”

Each time the ratio was found to be high, the “B” Sample was tested and found to not confirm the preliminary test. The second test is usually a carbon isotope test that is more specific to studying the makeup of the individual’s testosterone.

While the article goes on to say that one high number (of the T:E ratio) should be a once in a blue moon occurrence, there are significant genetic factors that can come into play.  A 2008 article published in The Journal of Clinical Endocrinology & Metabolism titled “Doping Test Results Dependent on Genotype of UGT2B17, the Major Enzyme for Testosterone Glucuronidationshowed that if an individual had two alleles for the UGT2B17 gene, there was a large chance that they would not test positive for cheating even after having taken a large dose of synthetic testosterone. The estimates were that 40% of individuals could pass the ratio examination just by virtue of having two copies of this gene. On the other hand with mixed alleles (ins/del) or in the absence of  this allele there was a fair chance that the ratio would always be abnormal. Estimates were that in a normal population, up to 9-14% of people would have a false positive result and fail the test.

It seems that if you have the del/del or ins/del variations of alleles, you are going to pretty consistently fail the test. The authors suggest that this gene should be tested and the results modified based upon the genotype of the individual.

Understanding the purpose of the Testosterone:Epitestosterone ratio testing and doing at least a brief look at  factors that might affect this test, not just once but repeatedly are important when an article such as the SI one is written. This specific gene and its implication on testing is widely known and has been covered in a variety of journal articles. The Canadian Medical Journal detailed, in an editorial titled “Doping, Sport, and the Community“, the difficulties in testing for Growth Hormone abuse and Testosterone. The editorial also mentioned research I came across elsewhere which indicated that many Asians (up to 40%) had the version of this gene that would give a false negative.

So, let’s get all the evidence out. And let’s make sure the public sees all the scientific information on the validity and the problems that exist with this particular test. For another perspective on heroes in American culture, you can seek out one of George Carlin’s last specials in which he expresses his opinion on hero worship and in particular on Lance Armstrong, Tiger Woods, and Dr. Phil.

The next test is to determine if the song “Bike” by Pink Floyd was written in a drug free state. In case you can’t make them out the lyrics begin:

I’ve got a bike
You can ride it if you like
It’s got a basket
A bell that rings
And things to make it look good
I’d give it to you if I could
But I borrowed it

Available video of Pink Floyd’s Bike (blocked currently at Youtube)

and if Pink Floyd is just not your cup of tea. Here is Queen performing their song “Bicycle Race”