Time/distance predictor...

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kirbyt
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Post by kirbyt »

Thomas said

I think there is too much mystique about the 2k. Every piece hurts in its own unique way... Go for it!
I totally agree. It is a really tough distance but I think we get so pysched out by it that we maybe don't just go ahead and try it from time to time. Come on people make 2k your friend. :shock: (I don't think shocked was the right emoticon but I like his bugged out eyes).

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Post by krisplus5 »

Okay, I finally got up the guts to just look at the predicted time for my 2K with some recent best-effort bands. I used my 1K and 5K, and came up with a 2:11.6 split goal. :?

This is way far off (for the worse) than my PB. In fairness, I am not as strong nor as young as I was back when I set that almost 7 years ago, and I've known that I couldn't come close to it today. And I think it may be time to reset my PB chart to my current age bracket... :lol:
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Re: Time/distance predictor...

Post by JonathanA »

I stumbled accross this when perusing the site last week. I used it to calculate predictions based on recent 2K and 30m times.

I don't know how you did it but they are all pretty close!

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Re: Time/distance predictor...

Post by Shang-Chi »

Apropos time predictions :!:

I used the time-predictions-calculator yesterday just see which pace I should use on 2K and what I was suppose to manage.

I used my 500 of 1:24 and my HM of 1:17:48.2 and the answer was: 6:17.6 :shock: If I used the 30 minutes time of 8545m instead, it was a little higher but still sub 6:20 :shock:

So I guess if I'm rested I will go sub 6:20 :D
Two months ago I did the same calculation and it told me 6:34 and I did 6:31.4. :wink:

I just hope it is correct. It is really bad if I arrive to Birmingham not able to do as predicted. :mrgreen: :^o
But it's sures give some selfconfidence and calmness. 8)

Anyway! Anything under 6:30 is okay with me. I can hope for no more. :D
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Re: Time/distance predictor...

Post by tiredboy »

For what it's worth this has been discussed quite a bit on the concept2 UK forum recently here: http://www.concept2.co.uk/forum/viewtop ... =4&t=17394
It appeared that for a lot of people the Paul's law value of 5 wasn't the best. There is a spreadsheet on the link above that allows you to calculate your own value for the Paul's constant based on the distances you've got PBs for and then use this value to predict other distances. This may be what the utility on here does but I don't know.
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Re: Time/distance predictor...

Post by Shang-Chi »

Hi Tiredboy
I looked at the spreadcheet, and I don't agree that it is done correctly.
Fore instance: The FM suggests 3hour 23 minutes (pace about 2:24) which is wrong. When I did 1000 in 3:12, and he does 3:06, I did FM in sub 2:47.00.0.
Pete Marston is right. It only works for him. I have done better than the predictions on our site suggests, so I guess it is calculated with some carefullness. It works.

I am supposed to do 2000 in sub 6:20, and I believe it's right. I did a try out earlier this year, and at 1300 meters my ending time suggested 6:15, and that was 3 month ago. I trust that the predictor works and is build on peoples experiences. So that makes me happy of course :D but it also place some pressure on my shoulders. :lol:
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Re: Time/distance predictor...

Post by tiredboy »

what do you think isn't right? The theory behind the spreadsheet calculation (ie the paul's law value of 5) of the actual calculations?
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Re: Time/distance predictor...

Post by Shang-Chi »

tiredboy wrote:what do you think isn't right? The theory behind the spreadsheet calculation (ie the paul's law value of 5) of the actual calculations?
I can't answer on this, its a feeling and knowledge of the runs I have made and seen done.

I'm not very good at math, and fail to see the use for it, when we have an exellent pace predictor on our hand. I will however try to see if the law fits my times but I dont see how, using the exampel of Paul's FM time. Pauls 2000m on 6;29.9 indicates a FM time between 2:45:00.0 and 3:00:00.0, not 3h and 24 min. I do 6:30 now and my FM must be better than 2:46:56.9 which I did earlier when my 2K was 6:42.0.

Annother problem is that we tend to put everything on formula, which has nothing to do with the human body. How are you day, did you eat well, sleep enough, are you tense, relaxed, happy, had a bad day, nervous etc. I think/believe it is impossible to put these "things" on formula. I blew the prediction on 2000 with 4 sec. and my FM is faster than other people that is faster than me on the short run. It's a tool and should be use for a layout of pace in a run, Sometimes you tend to start too fast and die in the end. This tool can give an indication of how stong your start, your middle and you finish should be, so you get as far as you can get with a good sprint in the end.

Cheers

PS: I think it is nice that you try to do better predictions. :D And I think it is a fun thing to use in my training.

Just added this:
My pace is anything from 4-9sec. in differencies when you double the distance. So in theory Paul's law could be right. But you can't say it is 5 second clean. It depends on musclefibers, fast slow long distance, how you are on the row, rested and so on. So the calculation is not an accurate way and should be known as such, but it could be a guideline for people in their preparations as the calculator on our site.
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Re: Time/distance predictor...

Post by hewitt »

just put my new times into the mystic predictor and it says i need to pb on all my times especially the 2k =P~ (it says 8 seconds but i am thinking more like 16 seconds :twisted: )
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Re: Time/distance predictor...

Post by Iain »

As I said on the PL thread on UK Forum, PL only seems to work >500m & <1hr. (i.e. for standard distances, 1k to 10k). Generally fit people can go quicker than predicted >10k, although actua times depend more on planned pace, motivation, experience of the distnce and how far the rower is prepared to push themselves much more than lesser distances. 500 and lower depend much more on strength and ability to sustain a good stroke at a very high rating. As such, not only does it not predict very well for times outside this band, but it is not as good when predicting from times in this band.

Also, Paul formulated this as a training tool whereby generally people significantly slower than predicted for longer distances would improve their 2k quicker working on endurance, and power would benefit those unable to meet short distance predictions. We would not expect as many people to fall into each camp. So the nonathlon scores showed that more people could improve 2k with power, i.e. concentrating on all distances up to HM neglected the power distances, hardly a surprise.

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Re: Time/distance predictor...

Post by hewitt »

I have just put my time in the predictor for the 5k and the 6k and it predicted that i should be doing a 2k in 6:26. :shock: :o =P~ That would definately be pushing it to far.(i think)
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Re: Time/distance predictor...

Post by johnglynn »

hewitt wrote:I have just put my time in the predictor for the 5k and the 6k and it predicted that i should be doing a 2k in 6:26. :shock: :o =P~ That would definately be pushing it to far.(i think)
With only 2 inputs the result can be very wrong if one of the times is stronger then another especially when so close together (i.e. your 5K is a decent amount stronger then your 6K) . Paul's law (which is reasonably accurate with only a single value) would give you a
5K - 6:41.1
6K - 6:44.6
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Re: Time/distance predictor...

Post by Stan »

Jason, I would say and I think Thomas would agree that you are better off using 2 different distances for the predictor -5k and 6k are too close to eachother. If you put in your 1k and 5k then it predicts 6:44. I think your 1k may be a little weaker (relatively) so using your 1 mile and 5k, 6:39 is predicted. My personal prediction for you is 6:35 :twisted:
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Re: Time/distance predictor...

Post by hewitt »

Thanks John amd Stan .6:35 sounds doable [-o< Suppose that i will have to wait a while longer for the dizzy heights of sub 6:30 (dam dam dam) :lol:
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Re: Time/distance predictor...

Post by mcperry »

I found the predictor spot-on. The straight line described by my 500 and 5k times predicted my 2k time exactly (to the second) . Of course I do understand that the efforts have to be truly maximal for this to be valid, but the beauty of this method is that it takes into account the individual's own tendency towards endurance or anaerobic power. I am a 400m runner and so my 500 row times are of far higher quality than my 5k times, but this is captured perfectly by the line traced between those points. In contrast, according to Paul's law I should be doing 2k in 6:49, but I am nowhere near as fast as that!
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Re: Time/distance predictor...

Post by Mike Channin »

Am I being stupid? I can't see any links to the mystic spreadsheet on the C2 Forum. Iain - do you happen to have a copy of it?
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Re: Time/distance predictor...

Post by Wolfmiester »

there's a link on the top of this page (under "links" and/or "utilities")
If I interpreted your post correctly?
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Re: Time/distance predictor...

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Re: Time/distance predictor...

Post by Mike Channin »

Cheers to you both - much appreciated
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Re: Time/distance predictor...

Post by HenningP »

Thomas W-P wrote: ...
My way relies on the fact that if you plot power against distance with log scales you get a straight line. If you have two maximum effort pieces you can determine the gradient and intercept, and from that predict any other power for any other distance and from that get the time...

My way is very hard to code in javascript so I am open to offers for simpler ways.
Maybe I can help to simplify the code – if my bad English does not hinder the understanding.
Your code relies on the idea that ln(distance) vs ln(power) is a straight line. It can be shown that also ln(distance) vs ln(time) is a straight line which makes everything a lot easier.
A straight line means the following:
ln(P) = m * ln(d) + c , where P ist power and d is distance. m is the gradient and c the intercept.
As P equals v^3 * k we can write
ln(v^3 * k) = m * ln(d) +c

The rules for logarithms say this is
ln(k) + ln(v^3) = m * ln(d) + c
or
ln(v^3) = m * ln(d) + c - ln(k)

If we substitute c for (c - ln(k)) – where the two c's are not the same – we get
ln(v^3) = m * ln(d) + c
which ist again the formula for a straight line.

According the rules for logs this is equivalent to
3 * ln(v) = m * ln(d) + c
or
ln(v) = m/3 * ln(s) + c/3
We substitute again and get
ln(v) = m * ln(d) + c
Also a straight line.

As v equals d/t we can write
ln(d/t) = m * ln(d) + c
According the rules for logs this is equivalent to
ln(d) – ln(t) = m * ln(d) + c
–ln(t) = (m – 1) * ln(d) + c
ln(t) = (1 – m) * ln(d) – c
If we substitute m for (1 – m) and substitute c for (–c)
we again have the form of a straight line like above:
ln(t) = m * ln(s) + c
This is equivalent to
ln(s) = (ln(t) - c) / m

So you have to calculate m and c from two points (ln(t1);ln(s1)) and (ln(t2);ln(s2)) like before but it is a lot easier and then you can easily find ln(t) from ln(s) and ln(s) from ln(t) without iteration. You don't need the power (Watts) at all. And then no cube or cuberoot is necessary any more.
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Re: Time/distance predictor...

Post by CamiCrew »

Interesting thread to revive and give input on, HenningP. Hopefully Thomas or someone else knowledgeable on such matters will catch sight of it to discuss it with you. Happy holidays.
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Re: Time/distance predictor...

Post by Stan »

I have drawn Thomas's attention to this post.
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Re: Time/distance predictor...

Post by jayney »

I've only just found the pace predictor, and giving it my 1k and HM times yields spookily accurate results for some of the longer rows... 5k was *exact*, down to the 1/10th, 10k was 2 seconds slower than reality, and 60 mins was 32m more than I achieved. All of those PB's were around the same time, when I was at my fittest in 2016. I was faster than predicted for the short distances though.
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Re: Time/distance predictor...

Post by obirobsan »

In my goal of resurrecting long dead topics, I found this. In the next couple months, I plan to refresh every distance to get an end of season number (well maybe not HM and FM because I’m a bit of a wimp). It looks this calculator says I have some possible SB (1k, 5k, 10k, 30 min, 60 min) — though only 60 min could be a new PB. I used my recent 2k and 6k SBs as the inputs.

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Re: Time/distance predictor...

Post by Ian Bee »

Well resurrected Rob.
20240302_212936~2.jpg
20240302_212936~2.jpg (86.43 KiB) Viewed 121 times
Based on my current 2k and hour, I have a good deal of work to do ...
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