A question about VDOT calculators...

[killerbeetle]

I'm curious... How does a VDOT calculator work? Does it measure your potential? How does a short race like an 800m or 1500m factor in?

[SteveF]

Not sure I can do this justice but... using a current known race time it will predict other distance race times and provide training paces. It's more accurate using longer races and provided you're running sufficient volume to justify the predicted times. For example my VDOT based on my 5k is 54.5 but based on my marathon its 51.1 so I get 2 different sets of training paces. This shows endurance is my weak point since I don't run the volume required. Its not made to plug in a goal and train off those paces. Train from where you are now, race, then re-calculate.

[killerbeetle]

I hadn't even thought of it in terms of training paces.

[Jwolf]

The race equivalency calculators figure out the longer distances by how much one typically slows down as you go longer (assuming you're properly trained for the distance of the longer running). This assumes even pacing over the longer distances.

They will be more accurate the closer the races in distance. That is, a 5K time will be more accurate to predict a 10K time than a 21.1K time. Short races like 800m and 1500m will predict longer ones like 5K, or even longer if you are properly trained for the distance.

It's important that the shorter race distances be accurately measured for the predictions to have any power, though. A 5K fun run might be off by a few hundred metres, and a minute of 5K would translate to much longer over longer distances.


As for the training paces--

The paces will be varied so that you do slower running for longer training runs and faster running for longer training runs. Generally the paces recommended for shorter running should total no more than about 15% of your total weekly mileage.

[QuickChick]

I mainly use them to get an idea of where I am at, but they are not a 100% accurate picture. Nor is McMillan, at least for me. What I do, and this might be totally off, but I look through the V-Dot table at the different training paces to get an idea of where I'm at, rather than plug in race times online to a calculator to get a number. I know my paces pretty well, but race times can vary depending on the weather, course etc. If you have "Lore of Running", it's on p. 312. I checked easy/long run pace and tempo pace first, as those are the ones I am most sure of. For me, 46 seemed about right (5:28 easy pace, 4:33 tempo pace). The one thing that is weird, though, is that when I have done short intervals, which hasn't been many times but will hopefully be more often, I was faster than the V-Dot suggested (about 40s for 200, suggestion is 46, about 1:27 for 400, suggested is 1:34). Faster than the "repetition" pace I mean- it says the interval pace in the V-Dot table is essentially your 5K pace. I don't feel like I train too fast, though- I am pretty consistent in my track workouts (I don't start off way too fast and get way slower). So if I used this table to get interval paces I think I'd be selling myself short a bit. Maybe he's assuming less recovery between reps, in which case I'd slow down a bit.

Based on the idea of 46 being my approximate VDot , I check the table on p. 72 where it predicts equivalent running times based on your V02-max. What I'm NOT sure of is if V-Dot is the same thing as V02-max- the numbers seem to line up, but why not just call it the same thing to avoid confusion??! There is no line for 46, but there is for 47, and they don't seem too crazy. Aggressive, but not crazy- if there was a line for 46 it would probably be pretty much where I'm at now. For 47 it predicts a 21:00 5K (I think I could do this on the right day), a 43:36 10K (already run faster than this, and this time seems totally do-able), a 1:12:22 10-miler (yes, on the right day this seems reasonable), a 1:36:36 half (eep, but I guess that's reasonable on the right day), and a 3:21 marathon (um, not anytime soon, but if I ran enough miles, maybe). So as the distances get longer the predictions are scarier, and it's not 100% accurate, but it's a good tool to keep pushing myself to aim higher.

[Joe Dwarf]

I like this calculator. You can plug in any vdot you like, or a known race and it will figure it all out for you. 46 tracks to a 21:24 5k or a 44:23 10k according to it. The way you're supposed to use it is to plug in your current numbers based on an actual race, not goal numbers. It then comes up with suggested training paces. This particular calculator is based on the charts that are published in Daniels' book. I haven't read the book but I assume Daniels came up with the numbers through statistical analysis of trained runners.

[Jwolf]

Based on the idea of 46 being my approximate VDot , I check the table on p. 72 where it predicts equivalent running times based on your V02-max. What I'm NOT sure of is if V-Dot is the same thing as V02-max- the numbers seem to line up, but why not just call it the same thing to avoid confusion??!

Lisa- i think the difference is that VO2max is an actual measured value (measured in the lab) whereas Vdot is just an approximated value based on race times. If you actually measure your vo2max in the lab it could be higher if you have non-running specific fitness (a la Lance Armstrong).

[ian]

Good discussion.

For example my VDOT based on my 5k is 54.5 but based on my marathon its 51.1 so I get 2 different sets of training paces. This shows endurance is my weak point since I don't run the volume required.

It took me until the end of last year (almost 6000K) to bring my marathon result in line with the shorter stuff. While your training paces can be chosen based on the higher VDOT values from shorter races, it is also nice to know the details about the lower VDOT data points, as I find that a somewhat experienced runner's VDOT "profile" often retains the same shape as they improve, i.e., an improvement of 2 VDOT levels in a shorter distance race over the course of a season will probably produce 2 levels of improvement in a longer race. This makes it possible to use short distance time trials to fine-tune marathon goals.

What I do, and this might be totally off, but I look through the V-Dot table at the different training paces to get an idea of where I'm at, rather than plug in race times online to a calculator to get a number. I know my paces pretty well, but race times can vary depending on the weather, course etc.

That's not unreasonable when you have a bit of experience. When I was able to resume speedwork in the spring after my injuries I was choosing my paces based on my perception of what the workout should feel like. As it turns out, I lost about four VDOT steps from the end of last year. Even in the absence of recent races, I can promote (or demote) myself based on these perceptions.

The one thing that is weird, though, is that when I have done short intervals, which hasn't been many times but will hopefully be more often, I was faster than the V-Dot suggested

That's not uncommon, in my experience, especially for runners under 40. Rest isn't an issue, as repetitions allow for complete recovery. So long as the technique is relaxed and efficient, the exact time isn't an issue (I often like to count the number of steps it takes to run 200m).

What I'm NOT sure of is if V-Dot is the same thing as V02-max- the numbers seem to line up, but why not just call it the same thing to avoid confusion??!

In addition to Jenn's point about physiological measurements versus race times, VDOT also accounts for things like weight and efficiency, i.e., V02-max tells you the horsepower of the engine while VDOT also includes the details of the rest of the car.