WHS: Athletics computer simulation: Discus throwing

WHS: Athletics computer simulation: Discus throwing

Up to ca. 1987 I did a lot of athletics, esp. Discus throwing, and to a lesser degree hammer throwing, shot putting, and long jumping. For discus throwing I was curious as to what the best angle of release is, and I made a computer simulation on my home computer in 1984-1985 (also for shot put and hammer, but that is trivial). The optimal angles for the discus were higher than I saw in reality (in my own throwing and on TV), about 40 degrees if I recall correctly (I will check the results later, it was many years ago!), so perhaps there was some error or possibly the issue is that throwing higher gives other problems: Less efficiency (not optimal to throw higher angles for biomechanical reasons). Another issue is that the rotation of the discus halts at long distances (and bigger angles make this problem worse at the end of the throw). I could clearly see this effect in my own throwing, if there was a strong headwind, at distances of ca. 42m+ already with the 2kg discus (a normal one, I think not an issue with a 'Supersegler', one of the first discuses with most of the mass near the edge, which I bought in 1986). Also, I didn't see in my calculations that headwind was beneficial (well, slightly, but so little as to be almost irrelevant), which I also felt was true from my own throwing, my best distances were always with nearly no wind. For distances close to 60m distances with the 1.5 kg this was true as well. Later, around the time that in the Dutch athletics federation magazine an assesment of esp. the new javelin was included in a technical section (1986), I called the people of that magazine, to see if they were interested in my results for optimal throwing angles, especially for the discus.

The results were especially interesting for the fact that the calculations showed, that what in Dutch is called 'scheppen' (shoveling, the pulling up of the discus in the end phase of the throw), gives longer distances... This way of throwing is taught as bad by coaches, but I think it can be beneficial, the more so the longer the throwing distance, though there is also a problem with it. The effect is that at release the discus has a negative inclination compared to its angle of movement, which means it will get a negative lift (will be pushed down) in the first part of the throw. After that the discus will travel flatter and also, the angle of inclination near the end of the throw with the movement, is smaller. This means the rotation will go on longer and the tipping over of the discus will be less... I didn't calculate the slowing of rotation, it was hard enough on my limited speed computer and not having equipment for measuring drag of the air from rotation etc. But all in all it was clear that this method of throwing could give results. I tried it ca. 1987 quite a bit, and at the time I felt that it seemed it could work, but I needed to do more throwing and to get a consistent technique with this method, because 'scheppen' tends to give a wobble in the discus so the technique to do it properly is not easy. But it is possible (at least throwing in the 40s, not sure how well it would work for say 60+ m). This consistency didn't happen as there is no proper athletics field close to me...

The guy I talked to on the phone was not indicating interest in the results of any computer simulations, he thought it was too specialised, and said something like "well, you can send it to us and we will have a look to see whether it's interesting". So as there was no interest, I didn't send them my results. It was curious that he didn't say "that is interesting" for something that at the time nobody had done (as far as I know)...

I will have a look at the program, run it again, and perhaps put some numbers here as to the differences in distances.

2015-9-6: Some more thoughts: My preferred throwing method is the jump-release (or semi jump-release), and as I had not seen any video of Jürgen Schult's world record throw even in the late 1990s, I asked him about it via the website of a German TV broadcaster. I think it was either 1998 after the European championships, or 1999 after the world championships. I'd need to check. This TV channel held a chat session on their site with the throwers. Nothing was reported about Schult's technique with which he threw the world record of 74.08 m in the reports that I had read. But some articles about him did mention that Schult experimented that year with the jump-release technique, and that later that year he was not in shape at all, which is why his performance was abysmal at the Euro championships in 1986 despite the world record... The question I asked Schult was: Was the world record thrown with the jump-release technique? Well, he said: "Yes it was thrown with the jump-release". But, why was he not in shape after the world record? Well, Schult was pressured to revert to the old technique, despite having thrown the world record with the jump-release. (I wasn't sure until I watched the Belgian documentary on youtube about eh discus WR, of why he reverted, I didn't get an answer to that question from him but in the documentary it was made clear their coaches in the GDR pressured him to change back or be forced to quit...). A change in technique inevitably means a loss of form for some time and he may have tried both. Already the initial change in technique is something that could result in a loss of form... What the exact reason was is hard to say, but he was not in shape for the euro champs 1986. But that he threw the record with the jump-release confirms my suspicion, that with the jump-release you can throw farther (though it is more difficult and results in more fouls), and that a world class thrower with standing-release technique can add distance when converting to the jump-release. Possibly not just because of more use of the legs, but also because more use of the legs means a negative inclination of the discus compared to the direction of movement, at the start of the throw, just like 'scheppen'...

2015-9-15: I retrieved some of my calculations and computer programs from the attic. For the final versions of these programs (not in BBC Basic) I made a screendump program (6502 assembler) and I made my own floating point routines in 6502 assembler with macros to give a simple compiler as otherwise it was just way too slow to do a lot of simulations... I will make some pictures of a few things and put it all on this page soon.

2015-9-15: Oh yes, and I have the documentation of the Supersegler, which didn't make sense to me. Berg's explanation as to why you would throw farther with it (than with a discus with less of its mass in the rim) is bogus...

2018-7-10: I looked up my saved html of the chat: It was by station MDR, on 1999-7-4, here is the HTML page from their site, of the chat during which I asked Schult whether the throw was with standing or jump throw: inhalt_aktuell_5531.html (I saved other pages with introduction and interview but these may be on the net, I could upload them if there is interest).

Well, mostly valid :) And no Flash, no Java, for a fast website... This site is made using open source software, in particular FreeBSD.

Last modified: 2018-7-10