TT road record on an athletics track
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Started
The guidelines state that a TT WR can be set on an athletics track. I wasn't familiar with the methods used to measure athletics tracks, but recently a number of things have come to my attention and I need to discuss them with you.
I've just read the following:
- the official distance of an approved athletics track is measured at 30 cm from the inside edge of the track for lane 1 (and 20 cm for the other lanes).
- the measurement of an athletics track is fixed, with no correction factor
- if the athletics track is not approved and has a special surface, then it is not possible to use the Jones counter method to measure it, because it's not possible to find a straight 300m calibration base that has the same type of surface
For athletics records, it's the official track measurement (30cm or 20cm from the inside edge depending on the lane) that's used for records, isn't it?
On lane 1, you can be 1m shorter than the approved distance for a 400m (riding 15cm from the edge). While this is of no importance for unicycle track records, as they are all achieved under the same conditions, it can raise questions for road records.
Personally, I think that the surface and the short distance of 400m are greater handicaps than courses on tarmac roads.
In any case, this is something that Samuel Coupey (who has done several road race measurements and who has just finished the athletics federation training course to obtain the diploma and continue with the measurements) is thinking about with regard to a forthcoming 100km record attempt on an approved athletics track by Aurélien Paulmier.
What is your opinion on the subject?
Comment
> For athletics records, it's the official track measurement (30cm or 20cm from the inside edge depending on the lane) that's used for records, isn't it?
For all atheltics records, the nominal distance is decisive - i.e. 400 m for one full lap. It does not matter whether the track is actually slightly longer than 400 m (which it may be according to the requirements of WorldAthletics). An officially measured track is always at least 400 m long and these 400 m are decisive.
> While this is of no importance for unicycle track records, as they are all achieved under the same conditions, it can raise questions for road records.
If a course is measured according to the requirements of WorldAthletics, this measurement is also made at a distance of 30 cm from the inside edge of the running surface. The measurement of WorldAthletics is therefore completely consistent between road and track races.
All in all, I would expect a lap length of 400 m for all time trail records set up on a track if the track is officially certified. If this is not the case, it must be proven that it is at least 400 m long and 400 m must be used as lap lenght. I would never use the actual length determined.
In my opinion, the Jones counter method has a completely different disadvantage: The method described by WordAthletics is designed to never measure too short. However, when measuring a short circuit that is ridden very often, this would result in the distance actually ridden being overestimated, as the distance of each individual lap would be set too high. The method - as described by WorldAthletics - is therefore not suitable for measuring a single lap in races with several laps.
Comment
> If a course is measured according to the requirements of WorldAthletics, this measurement is also made at a distance of 30 cm from the inside edge of the running surface. The measurement of WorldAthletics is therefore completely consistent between road and track races.
You're absolutely right. I should have checked the World Athletics reference text before comparing the "shortest possible route" and the trajectory "30 cm from the kerb". This 30 cm is also indicated in the road race measurement reference text.
Thanks for your quick reply, it's reassuring that there's consistency between the measurements for track and road races.
> However, when measuring a short circuit that is ridden very often, this would result in the distance actually ridden being overestimated, as the distance of each individual lap would be set too high. The method - as described by WorldAthletics - is therefore not suitable for measuring a single lap in races with several laps.
The correction factor of 1:1000 is used to guarantee the official fixed distance. It's like measuring 100.1km instead of 100km. In an 100km attempt, to set a fixed distance record on a loop, the distance of the loop will be underestimated in the calculation.
You need to use a correction factor, because you can't guarantee the measurement, as you could when building a track.
Comment
I always thought the measurement is taken as the inner perimeter of the track, for all time trial records. By definition every time trial record distance is greater than the actual distance measured by a factor of 2 π the distance from the measured inner perimeter.
Jones counter is for measuring courses that take place on roads, with twists and turns, rather than a track.
If indeed athletics don't use the inner perimeter for their measurement, then I don't agree with this. Do we need to follow athletics for every rule?