Cross Team Challenge - Discussion Thread

[jackarabit]

An even more extreme case: the 100m and the full marathon. Certainly true that 1" improvement per (500m) split at marathon distance is ~84.4" chopped off total time and at 100m .2". Such an insignificant itty bit as a hundred meter is hardly worth considering in the greater scheme of things until one comprehends the immense power necessary to produce so little so very quickly. I admire sprinters; hustlers not so much.

[Bob S.]

I admire sprinters; hustlers not so much.

Is there an implication here that I am missing? Not that it is any of my business, since I have no interest in the challenges other than a morbid curiosity.

Bob S.

[jackarabit]

Bob, those whose business it is are, imo, well-positioned to comprehend an objection to a formalistic mumbo jumbo which apes the lingua franca of competitive indoor rowing while intentionally altering or abandoning well-understood, commonly-accepted meanings of "pace," "time," and "average." I am implying that I don't approve of designing challenges full of lawyer gas and dialectic flips and spatters. I am saying that I don''t! It is particularly bad form to bemoan innumeracy as exhibited by CTC participants while touting the instrumentality of a mathematical fiction.

[stupefaction]

intentionally altering or abandoning well-understood, commonly-accepted meanings of "pace," "time," and "average."

I have been using the commonly accepted meanings of "pace", "time", and "average". In erging, we express pace as time per distance, with the usual unit of distance being 500 m. Time is measured in minutes and seconds. The average of several values is their arithmetic mean.

The unweighted average of N values x1, x2, ..., xN is their sum divided by N:

(x1 + x2 + ... + xN) / N

The weighted average of those values, using weights w1, w2, ..., wN, is:

(w1 * x1 + w2 * x2 + ... + wN * xN) / (w1 + w2 + ... + wN)

Suppose we want to compute the average pace achieved over two distances. An athlete takes t1 seconds to complete d1 meters, and in a separate effort takes t2 seconds to complete d2 meters.

What do we mean by average pace? Most often we mean:

(t1 + t2) / (d1 + d2)

This is the weighted average of the paces, with the weight being assigned in proportion to the distance.

To see why, note that the pace for each distance is:

p1 = t1 / d1

p2 = t2 / d2

The average of the paces weighted by distance is:

(d1 * p1 + d2 * p2) / (d1 + d2)

= (d1 * t1 / d1 + d2 * t2 / d2) / (d1 + d2)

= (t1 + t2) / (d1 + d2)

Now consider the unweighted average of the paces. We do not take into account the distance over which each pace is achieved. We compute this value:

(p1 + p2) / 2

That is the essence of Nick's proposal for next month's CTC. Entries will be ranked according to the unweighted average of four paces:

(p1 + p2 + p3 + p4) / 4

The number that Nick proposes we enter on the CTC page is the sum of four paces, each of which is expressed in time per 500 m. In other words, your score is the time per 2000 m, which is equal to four times the unweighted average pace per 500 m:

4 * (p1 + p2 + p3 + p4) / 4

= p1 + p2 + p3 + p4

It doesn't really matter whether the unit of distance is 500 m or 2000 m, because the rankings end up exactly the same. Pace is always the ratio of time to distance, regardless of what unit of distance you use to write it out.

[Citroen]

Thanks for that explanation, it makes much more sense to use your weighted average.

[hjs]

Thanks for that explanation, it makes much more sense to use your weighted average.

Yes, but thats not what the guys want, they want every rep to be equally important, so unweighted, making this ctc the most extreme in terms of power thus far.

[lindsayh]

Thanks for that explanation, it makes much more sense to use your weighted average.

Yes, but thats not what the guys want, they want every rep to be equally important, so unweighted, making this ctc the most extreme in terms of power thus far.

Yes that is what I imagined - it is unweighted by simply summing the rate/500m for each of the 4 pieces?
I think that is what the sprint people wanted - have to admit it is different

[jackarabit]

. . . different.

Yep, like squid ink is different from rainwater!

[Paul Victory]

Just a thought, but one way of setting this up so that people don't have to work out their average pace would be to allow each individual to set it up as a variable interval session, with complete discretion to how long they specify as a rest period (although there may be a 10 minute limit on what can be programmed).

I know this would weight the three distances rather than take the average of the three different paces, but it would allow something closer to maximal performances, with the advantage of allowing rolling starts for the second and third intervals. You could also allow people to choose in what order to do the three pieces.

[joe80]

There's no sign of the ISS forum awakening from its protracted slumber. I've put together the table showing October's challenger from the primary source, that is, the CTC site. Only active months count and just the teams that have made an appearance this season are shown.
The challengers for October are Paddy Power. FIRT have an equal number of points but, in such a case, months since the previous challenge take precedence. SkiErg have made three consecutive entries so, as a new team, they get the challenge for November.



Regards,
Joe

[macroth]

Just a thought, but one way of setting this up so that people don't have to work out their average pace would be to allow each individual to set it up as a variable interval session, with complete discretion to how long they specify as a rest period (although there may be a 10 minute limit on what can be programmed).

I know this would weight the three distances rather than take the average of the three different paces, but it would allow something closer to maximal performances, with the advantage of allowing rolling starts for the second and third intervals. You could also allow people to choose in what order to do the three pieces.

I was wondering what other ways there might be to emphasize sprinting ability without having to use a calculator, and this may be as close as it gets. PM4/5's allow for undetermined rest periods, but I don't know if they time out on their own after a while.

[macroth]

On a separate note, judging by my signature I haven't been on this forum in 6 years. Only my height hasnt' changed.

[joe80]

Just a thought, but one way of setting this up so that people don't have to work out their average pace would be to allow each individual to set it up as a variable interval session, with complete discretion to how long they specify as a rest period (although there may be a 10 minute limit on what can be programmed).

I know this would weight the three distances rather than take the average of the three different paces, but it would allow something closer to maximal performances, with the advantage of allowing rolling starts for the second and third intervals. You could also allow people to choose in what order to do the three pieces.

I was wondering what other ways there might be to emphasize sprinting ability without having to use a calculator, and this may be as close as it gets. PM4/5's allow for undetermined rest periods, but I don't know if they time out on their own after a while.

From what I understand of the Sprint Group's posts, the intention is not to row this as an interval session but to go for maximum efforts, perhaps on different days. There's no reason why it can't be a single interval session but that won't help with the simple maths. Adding three or four splits together should not be much of a problem; if it is, help is available.

Regards,

Joe

[joe80]

The following web page computes a score for 400/300/200/100 as described by Nick.

http://michaellaszlo.com/ctc-helper-august-2016/

For example, respective times of 1:21, 0:51, 0:33, 0:16 yield a score of 5:37.5.

There's been no recent discussion or input from The Sprint Group. My impression is that the August CTC will be:

100/200/300/400 metres separately performed at any time during the month from standing starts. The pace splits for the four rows should be added and entered on the CTC site. There is a calculator available http://michaellaszlo.com/ctc-helper-august-2016/ where the raw times may be used to produce the valid entry.

Hope this is correct. If there's no amendments, I'll publish it in the facebook group tomorrow.

Thanks Stupefaction for generating your very handy calculator.

Regards,

Joe

[lindsayh]

100/200/300/400 metres separately performed at any time during the month from standing starts. The pace splits for the four rows should be added and entered on the CTC site. There is a calculator available http://michaellaszlo.com/ctc-helper-august-2016/ where the raw times may be used to produce the valid entry.

I agree Joe - that is how they expressed their intention.