ISEA Conference – Points of interest Day 2

By wiredchop

Day two in Vienna and all’s going well, the conference started off with a fantastic keynote lecture by Benno Nigg discussing impact forces and muscle activation in running. It was interesting to note he stressed the importance of muscle activation in the running strike and not just peak force, which has been used recently to promote barefoot running. Muscle activation is a good indicator of fatigue levels and should reveal if wearing trainers can reduce the effort required to run as there’s been no evidence that running barefoot reduces injury.

He also mentioned that the promotion of barefoot running roughly has a 25 year cycle (big news in 1960, 1985 and 2010), if this blog is still going in 2035 and barefoot running becomes big news again I’ll try to remember to mention it. (See here for some videos of Benno and more detail on his work)

A lot of football aerodynamic papers today all with some really interesting results.

See this paper for some very interesting flow visualisation using clouds of (toxic?) titanium tetrachloride. It shows the wake of the ball oscillating with time, suggesting an oscillating force creating a ‘knuckleball’ effect.

To follow up, this paper visualised the flow after an Adidas Teamgeist ball from a wind tunnel and found that even when completely stationary, the direction of the force oscillates with time at high velocities.

A great paper from Norway looked at a number of balls including an Adidas Europass (a pimpled Teamgeist) and found that at low velocities the Adidas ball is at risk of ‘reverse swing’ an effect in which the ball curves in the opposite direction to which you might expect.

Every presenter seemed to agree that a football that is too smooth and too round is likely to behave oddly when compared to a more traditional design. However they did concede that players may get used to this effect with time.

A number of Sheffield presenters today all doing fantastically, Heather Driscoll got lots of praise regarding her work in the photoelastic effect and football stud traction and it was a great conference debut.

John Kelley presented a program he’s developed that measures the spin and speed of a tennis ball using only a single high speed camera. With some developments it would be great to see this technology used during live match play in order to see just how fast and spinny (must cut down on the techno-jargon) shots are from the top players. It would also be interesting to see just how wrong the commentators are.

Half way through, I’m presenting tomorrow, off for a practice.

Simon Choppin

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About wiredchop

Simon Choppin Simon’s sports engineering career began at the age of six when he loosened the wheels of his skateboard in order to make it go faster. While the experiment was chalked up as his first failure, his resulting dimpled skull has provided an aerodynamic advantage in more recent sporting pursuits. Academically, Simon completed a degree in Mechanical Engineering with Mathematics at Nottingham University before joining the Sports Engineering Research Group at Sheffield to start his PhD. His main interests include work with high speed video, mathematical modelling of various sorts and experimental work involving machines with big buttons. As a sportsman, Simon has an unfortunate lack of talent for anything requiring skill, tactical awareness or the ability to learn from mistakes. He does however seem to posess the ability to move his legs around for a long time until other people get tired, for this reason you’re most likely to see him on a bike of some sort or running up a hill in offensively small shorts. Simon was fortunate enough to have a stint at the Guardian newspaper as part of the BSA’s media fellowship, which gave him the idea for this blog. Other than this, his writing experience includes his PhD thesis and various postcards to his Mum.

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