Just interested in the math, if anybody knows what goes into that calculation.
Just interested in the math, if anybody knows what goes into that calculation.
Most likely a regression equation or Percertage trend line type situation. Which is where some of the trouble lies. The IAAF scoring tables do a much better job at giving a race time a certain "value" to race distance. Some calculators will say a 15:30 is worth a 2:28 marathon when a 2:28 marathon is much harder to achieve. The IAAF 15:30 5k will only give a you a 2:36 marathon eqivalent.
Mathproblems wrote:
Most likely a regression equation or Percertage trend line type situation. Which is where some of the trouble lies. The IAAF scoring tables do a much better job at giving a race time a certain "value" to race distance. Some calculators will say a 15:30 is worth a 2:28 marathon when a 2:28 marathon is much harder to achieve. The IAAF 15:30 5k will only give a you a 2:36 marathon eqivalent.
I completely agree. I’m mostly interested in knowing how exactly it gets calculated and whether, along similar lines, it would be possible to project out to someone’s 10-hour race pace if we know their marathon time. I understand it wouldn’t be terribly accurate but still curious.
Here is a pretty detailed description of how the Daniels calculations work.
parkerjohn wrote:
Just interested in the math, if anybody knows what goes into that calculation.
Don't know about McMillan but my favorite estimaters are Daniel's VDOT and Purdy Scores.
Daniels' tables are tools that can be used by one athlete to help estimate his training paces and race targets from a known race. Purdy is a way to compare the performances of two athletes at two different distances, including sprints. (VDOT can also do that for 1500m and longer.)
Daniels: Jack Daniels and Jimmy Gilbert measured oxygen consumption of athletes at various speeds and came up with the formulas to correlate them:
percent_max = 0.8 + 0.1894393 * e^(-0.012778 * time) + 0.2989558 * e^(-0.1932605 * time)
vo2 = -4.60 + 0.182258 * velocity + 0.000104 * velocity^2
vo2max = vo2 / percent_max
From these formulas, they created lookup tables for many race distances to allow you to find "equivalent" performances. These formulas and tables were first published in 1979 in "Oxygen Power". They are generally considered applicable for 1500m and up, but even then individual athlete performances will vary depending on aerobic fitness.
Purdy:
Originally, based on Portuguese Scoring tables (itself based on the 1936 World Records) by arbitrarily assigning these 1936 World Records a score of 950. The velocities associated with all the World Record distances (from 40m to 100km) are used to create a table with which to compare your own velocity at a chosen distance.
k = 0.0654 - 0.00258*v;
a = 85/k;
b = 1-950/a;
p = a*(t950/tsec - b);
Note this was updated in 1970, equating 1970 performances arbitrarily to 1035 and using a "least-squares fit". This makes it easier to calculate without a lookup table.
Some links for more complete info and proper credit (Purdy code somes from C-Code from Patrick Hoffman -- original link no longer available, but it can be found with the Wayback Machine):
...
The IAAF tables were originally based on the Hungarian tables (similar to Purdy and the Portuguese scoring tables).
The IAAF tables get updated based on new performances.