11 replies to this topic

[hatless]

G'day everyone,

In light of a few comments on the temperature thread, I thought I'd have a look at the data to see if there has been a big change in the times that the field is achieving on the 6FT over the last 25 years.

I used the median as well as the 25% and 75% quartiles of race starters from each year to look at the times for each year.

Look at the first attached graph. A few quick observations:

1. The fields in the first three years were quite slow and quite small
2. The golden age seems to have been in the late 80s
3. From 1990 to 2006 the field grew dramatically in size, and the median time got slower
4. The last two years have been comparatively quick years.

So we might well conclude that the golden age was in the late 80s and things have gone downhill ever since.

However, while I am in no position to refute that the late 80s were indeed a golden age, the idea that times have gotten progressively worse is a little misleading.

From the analysis behind the temperature thread, I observed that, on average, a one degree change in the average tempterature on race day between 8am and 2pm causes a 0.81% change in race time. So I normalised the median times for the years I have the temperature data (1990-2008, excluding 1997). That is, if a particular day was 2 degrees hotter than the average race day, I reduced the times by 1.62%. The results are in the second graph.

There is an ever so slight increase in times over this period, but nothing that anyone would notice.

So in conclusion, if you don't have a Six Foot jacket hanging in your wardrobe (ie you're an 18-time finisher), then you probably can't hark back to the "good ol' days."

Best of luck with the final weeks of training,

h.

Attached Files

•  Meadian_times.jpg   59.66K   65 downloads
•  Adjusted_median_times.jpg   46.09K   50 downloads

[Hamburglar]

We could use this data to prove climate change!

BTW - hasn't there been a course change sometime in the last 20 years which made the track shorter?

[undercover brother]

ignore the data.
the quickest year was the one kev did a 4.11
its all been downhill from there.
now how many six foot threads can we get cracking over the next few weeks?

[EXE]

I suspect that there has always been a small but slowly expanding group of "hard men" (no gender bias intended) that filled the sub-five hour category.  The big growth in entrant numbers has come from the wave of "new runner enthusiasts" who tend to fill the over-five hour category.  At the pointy end times are actually getting faster.   An increasing number of new runners are doing their first Six Foot with slower times and giving the seven hour cut-off and sweepers a bit of a work out.

Back in the "golden age" finish times were distributed with a "long thin tail" but today there is a "fatter tail", so to speak.

This would neatly explain an increasingly slower overall median time.  Lies, lies and statistics.


EXE

[yeti]

EXE, on Feb 16 2009, 04:27 PM, said:

I suspect that there has always been a small but slowly expanding group of "hard men" (no gender bias intended) that filled the sub-five hour category.  The big growth in entrant numbers has come from the wave of "new runner enthusiasts" who tend to fill the over-five hour category.  At the pointy end times are actually getting faster.   An increasing number of new runners are doing their first Six Foot with slower times and giving the seven hour cut-off and sweepers a bit of a work out.

This would neatly explain an increasingly slower overall median time.  Lies, lies and statistics.

Lies, lies and statistics indeed    The temperature adjusted stats (see hatless first post and also my post in the temparure thread ) not only suggest that times have, in fact, gotten better over time if you take the temperature into account, but that the back end of the field (75th percentile) improved more and with higher statistical significance than the fast ones (25th percentile).
Caveat (for the real mathematicians out there): This is just a quick & dirty analysis. To do it properly one would need to take into account that the year and the temperature are not really independent variables but are correlated themselves (a linear fit shows r^2=0.11). OTOH the data set is most likely too small (17 data points) to yield statistically robust results anyway.

Yeti

[Spud]

Some interesting graphs again, thanks Hatless.I reckon one of the contributors to the faster medians over the last couple of years (apart from the cooler weather) is course knowledge. There are more and more trail enthusiasts training on the track in the weeks/months leading up to race day. The number of runners between 4.45 and 5hrs last year grew exponentially. I bet we'll see the same thing happen this year in the 4.30-4.45 bracket (weather permitting of course )

[Jogger]

hamburglar - there was a course change to make it a bit shorter, but harder.
In my opinion, the net effect was a big fat zero.

[Spud]

JoggerKev, on Feb 17 2009, 06:42 PM, said:

hamburglar - there was a course change to make it a bit shorter, but harder.
In my opinion, the net effect was a big fat zero.

so course records from both are comparable?

[Colin]

I would find it hard to believe that a 1.5km difference (I'm assuming 46.5 vs 45km) over such a short distance at the deviation would have a zero effect, no matter the hill at the deviation...not even for the tail end who walk the hill slowly.
imo, if say the old section was 6.5km vs 5km for new (even a shorter section if you confine only to difficult bits, i.e.flat parts are equal) then the leaders would have to run the latter at 1:24/km slower (over the whole 5km).

It is only anecdotally said to have a zero effect because the records didn't improve much.

As for the median and especially 75th percentile improving, one must take into account that the quality of the entrants at tail end are controlled to start off with-so shouldn't get worse. There is also a greater amount of trail runs used as qualifiers, plus the training runs those runners do. (Spuds point).
You do not get the demographic of >4:30 runners entering 6ft.

cheers

[Jogger]

Quote

so course records from both are comparable?

I believe so.
Maybe one weekend we can go up and both sections as proof.

[ScamBullant]

These quantitatively minded individuals are providing all sorts of interesting statisitical evidence on field capabilities through history.

Surely what is required now is a qualitative study looking at a handfull of individuals over the given period and studying in depth their performances taking all variables into account over this time.

Just to help support or rebute said suggestions. (I recon dats pridy god 4 a Pe Techa).

[hatless]

I have cut the data into 30 min chunks to look at the proportion of starters who ended up in each bucket. The first diagram is for all races back until 1984. Two things stick out:

1. 1987-89 was a real golden age. No doubt about it
2. There has been a huge improvement over the last 2 years.

I have done the same graph for the years since 1990 with the bands adjusted to take into account the temperature. This is the second graph. Two things stick out from this:

1. The cohort of 1991 must have been using some sort of solar powered device
2. There has been a noticeable improvement in the 4:30-6:00 crowd in the years 1995-08.

So in summary, unless you already have a belt, you have seen nothing but improvement in your time.

Cheers,

h.

Attached Files

•  Distribution_times_30min_inc.jpg   104.51K   47 downloads
•  Adjusted_distribution_times_30min_inc.jpg   92.54K   52 downloads