Top throwers wanted!

Almost by accident, I’ve managed to get access to a state-of-the-art lab at the Institute of Motion Analysis & Research at the University of Dundee, and the help of the experienced technicians who run it, for something like 10 full days this summer. This is going to be fun…

We’re going to get some data on throwing techniques for a whole bunch of people, and we’d really love to have some top throwers – male and female – come and join us. We’re looking at variations in technique and the effect these have on the ability to generate power and spin. Obviously we’d love to study some people who can throw it 80 yards – but we’d also be very interested in people who can throw it 60-70 yards despite not being able to bench-press a boiled egg. People who throw well with particularly short or long arms. People who have a reputation for throwing particularly well in wind. People who do something a bit weird but still get results.

The brief version – we’re going to get 40-50 people into a laboratory over the coming months, where we’ll do motion-capture of a bunch of throws, and then we’ll look for correlations between the way people do it and the results they get. Hopefully, we’ll get some really top throwers, and some intermediate ones, and we’ll look at the differences. Nothing quite like this has been done before, to my knowledge (shout if you know of anything!).

One paper (Hummel thesis, chapter 4) studied one thrower in similar detail, but was unable to compare the technique of that one player with others, and hence does not offer a more rounded view of where power is generated or what effect different styles have or any of those things. In short, we stand to learn an awful lot, and then we’ll write it all up as an academic paper – and some blog posts too!

Here’s the geeky (but to me, vastly interesting) version. Skip to the end now if detail isn’t your thing.

The thrower and the disc are dotted with about 30 reflective markers, on all the joints (wrists, knees, shoulders etc.) and other places of interest. These markers are then picked up in real time by around 15 cameras working at 400 frames/second. For every marker, for every frame, we get the position (accurate to around half a millimetre in 3 dimensions), and also the velocity and the acceleration. The distance between any two markers, or the angle between two or more, can also be automatically calculated.

[To give you a clue about the accuracy of this stuff – looking at the marker in the dead centre of the disc, our test-runs pick up a tiny repeated oscillation in the z-axis (up and down) after release. As far as we can tell, this seems to be caused by the flexing of the disc – it deforms slightly when you pull on it, and after you let go it flexes back and forth for a while… If that isn’t cool, then you’re reading the wrong blog.]

We get information such as how fast or how many degrees the wrist snaps, how many degrees the shoulders turn, the amount of bend in the elbow at release, how much the hand is accelerating at release; pretty much anything we want, at 400 frames/second. We also get ‘result’ information – the velocity and spin of the disc after release, and (across a number of trials) how consistently you throw it in the same direction. We’ll also measure things like the thrower’s lever-length and basic strength, in case we need to adjust for these factors.

Then we look for qualitative patterns and for quantitative correlations between all the things we’ve measured and the results we get. How much of the velocity of the disc comes from the arm-speed, and how much from snapping the wrist? Do you get more spin by consciously flicking the wrist, or by keeping the wrist fairly stiff and letting the disc flick off the fingers? Does whipping a forehand from the elbow result in more spin or power than a less whippy motion? You might think you have an answer to all these already – but wouldn’t it be great to know?

Clearly, we need to be careful with our stats. If we look at a lot of things that we think might influence results, then there’s a goodish chance that some of them will correlate just by chance. Perhaps more research will be needed on the things that appear to be flagged up by this research. We don’t know yet how noisy our results will be. But it’ll be fun finding out – and we may just come close to answering some interesting questions of technique.

And for those who are reading this and thinking we could never measure anything game-like – people’s ability to vary their throws, their accuracy at hitting a moving target, their decision making – well, of course you’re right. All we plan to do is to ask people to throw a bunch of flattish backhands and forehands, at the comfortable limit of their power (so not over-throwing) and see what sort of biomechanics lead to what result. It won’t define what makes a good thrower. But it just might give us some clues about how we create spin or power or consistency that will help us to coach or to learn.

And since we’re already in the lab, and the time-consuming bit is to cover the body in markers, we’ll also get a ton of other data which we might not have chance to fully analyse any time soon. Recording extra throws is extremely quick and painless. So we’ll get people to over-throw the disc, to try too hard, and see what if anything is different when it goes wrong. We’ll maybe get people to throw deliberately with extra I/O or skip curve and see precisely how they achieve that. If someone really wants a stick-man video of themselves throwing a scoober, we can do that too. And if someone comments below with a good idea, we’ll add that in.

So – if you’re going to be in Scotland any time between now and September, get in touch and get tested. It’s going to be awesome.

Fill in the form below if you want to join in, or drop me a message through the facebook page if you want to recommend a particular player I should get in touch with, or for any other queries.

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