Predict your next marathon finish time…

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If you’re anything like me, I like knowing where I stand with my training. It is nice to gauge my overall fitness level at various points during the year and determine what to expect from a given race. Bart Yasso has his “Yasso 800s“, a company called Quantitative has a running calculator (and even one for triathlons…but that’s for another day). There is one that is consistently regarded as the best in class…You may have even heard of it…The McMillan Running Calculator. This particular system was developed by a man named Greg McMillan. He is a scientist, coach, and runner who has all the grooming to be an elite level running trainer. In his own words he says,

“I haven’t found one[running predictor] that is specific enough, is laid out in an easy-to-read format or that is based on what runners in the real world are capable of doing. So, I created my own and I’ll share it with you.”

Before we dive in to McMillan’s world of race predicting, let’s first briefly discuss some other major players in this arena. First up:

Bart Yasso and his amazingly painful “Yasso 800s”

bookpicThe History: A man named Bart Yasso noticed a direct relationship between his 800m track workout pace and his marathon finish time. If he was consistently running his 800s in 2 min 50 sec during a given training cycle, he could expect to finish that marathon in 2:50. Since he works at Runners World, he was surrounded by people willing to give it a try, namely Amby Burfoot who later wrote the article that started it as an official training component. People soon found that it did a pretty decent job of predicting marathon times for people at various fitness levels.

How it Works: About 10-14 days before your marathon, you find a track to run on and run a 10 by 800m workout. The mindset going in is to keep your 800s within a few seconds of each other for all 10 of them while pushing yourself to find the limits of your fitness. You then take the average of your 800s and convert from minutes/seconds to hours/minutes for a race prediction.

The Assessment: While this workout has proven to be pretty accurate, it doesn’t really help you during your training much. Sure you can do 800s and figure out where you stand along the way, but you still have to do the long runs, the tempo workouts, and yes, even the recovery/easy jogs for this to be accurate. In the end, I believe this to be a valid piece of your training plan.

For more info on the history and workings of the “Yasso 800s”, click here.

Quantitative’s “Run Calculator

picture-11The History: Quantitative is a triathlon training company that offers services and coaching in the multisport world. They have developed their own prediction calculators to suit the needs of their particular clientele. In addition to their “Run Calculator” they also have a “Triathlon Calculator”, which will help predict Ironman finish times…

How it Works: There are main differences between this predictor and the Yasso 800s. The first being that there is no specific workout laid out to determine your fitness level. It does however require that you have run a 5K in the near past. The second difference is that they ask for a training volume in the form of weekly mileage from your highest weeks during the training cycle.

The Assessment: Two main benefits of this prediction calculator are that 1 you don’t have to do a pretty hard workout to figure it out, and 2 it allows you to put in any race distance you like…not just a marathon or other standard distances…Say you are training for a 15K or some other non-traditional distance, you just type that in and let it calculate away. The downside here is that, like the Yasso workout, you can only really know the prediction towards the end of your training. Again this is another good tool to use, but not to base any training plan on.

McMillan Running Calculator

picture-4The History: As quoted above, McMillan had some frustrations with the other running calculators out there and decided to create his very own that has a more realistic and real world approach to race and training predictions/calculations. His calculator is based on distances and times you already have run, like a 10K time, and bases the entire training targets based on them…

How it Works: You select a distance you have run recently (preferably in a race environment) and enter the finish time. What results is a veritable smorgasbord of running distances, paces, and targets. There’s a lot there, and I’ll attempt to demystify it later, but for now, we’ll focus on the workings of the calculator…Another way to use this is to put in a predicted marathon time and use the results within your training plan so you can constantly stay up-to-date with where you are and how your training is going. (Warning: for runners with a bit more experience or a larger sense of adventure).

The Assessment: The title of this post is about this particular calculator, so I personally believe it to be one the best out there. That said…here’s why. The first part of the results shows you finish times for lots of distances, from 100 meters all the way to marathon. This can be used as an additional way to gauge your fitness as you compete in races (which we should all be doing) during the training cycle…Often we call these B races. You should be always assessing your training and what areas need improvement and what areas you can really use to help your training go smoothly. The middle sections give you training paces for multiple distances like your long run paces, recovery run paces, tempo runs, and all of the speed workout distances (100m to 1800m). All in all, this calculator gives you pretty much all the data you will need to be successful in your training for any distance, as well as have a daily gauge of your overall fitness.


How To Use McMillan’s Race Calculator


There are many ways to use this calculator, and most of them are perfectly valid. I’m just going to step you through how I have come to use this tool in my own training regiment.

Enter Your Data: Pick a race you’ve completed recently that you feel shows a good picture of your best current ability. For this example I’ve chosen a recent 5K time of 21:29

McMillan Data Entry Form

Hit “Calculate” and you’re off and running

Quickly assess the accuracy of the calculations: Take a look at the top-most section of the page that shows the various distances and predicted times for each. You should be able to agree with most of them as you scan across the list from a prior race or tempo run perspective, not training distances.

Distances & Paces

If the calculations appear to be close to what you have previously done or assumed you were capable of, move on to the next sections, if not, enter a different past race or distance/time and try again until it does match up better.

Long Run, Easy Run Pacing: The left section directly below the top shows you the pacing you should be hovering around for your long runs, easy runs and recovery jogs. You can use this as another way to ensure the accuracy of the calculations and, assuming they’re correct, use it as a guide for keeping your runs within the right tolerances. As I’m training, I usually struggle with keeping my long runs as slow as they should be according to McMillan, so this is a good reminder to keep my long runs…long and slow…

Long, Easy, Recover Run Pacing

Tempo/Stamina Workouts: On the left directly below the previous section is the section regarding your tempo/pace/stamina workout pacing. If you aren’t doing Tempo workouts or Pace Runs you should be, so use this section and do them. Here’s how to use the calculator data…The “Steady State Runs” should be any workout where you are running say 10K or longer distance but shorter than your long run distances for that time. You want to be consistent in the pacing here. Use a GPS watch or a known course to manage the distances and times. The “Tempo” workouts should be listed in your training plan…if not, check out these training plans by Hal Higdon.


Speed Work/Track Workouts: Speed workouts are possibly the most effective part of any endurance training. Logic (at least my kind of logic) would hold that speed workouts should be left for those running those distances…in other words…sprinters or middle distance people…not endurance athletes like us, right? Well, it turns out that these speed workouts can have a profound impact on our overall endurance. I’m not really qualified or confident in my biology skills, so I will just say this: speed workouts push your body past the lactic threshold of your current fitness level. Lactic acid is what makes you sore, but it also contributes to muscle fatigue during activity. The more you push your body past this point the more endurance you’ll have when it comes to those long distance events… You could accomplish the same thing by running a marathon every Wednesday in preparation for your marathon, but then you would’ve already run your marathon, and that not only doesn’t make sense, it’s also unpractical. Speed workouts are a much better, quicker, way to get the fitness level you need for your big day.

On to the use of this part of the calculator…Just like the Tempo/Stamina portion, you’ll find this helpful to you when preparing and actually doing your workout. Using the numbers as a guide will give you a good starting point for your pacing. For me, I generally find myself running towards the faster side of the range given. You may not find yourself there, and that’s ok, just remember that these are guidelines, not to be considered as gospel…


Click here for the McMillan Race Calculator tools

Remember, these are just tools to aid in your training. You may not even find much help from them, some people don’t want/need all the data and technology, they just want to run. Some people will get a lot from these tools as both a starting point for their training and a constant gauge of their various fitness levels. Don’t forget, however, that you still have to do all the hard work and training to get there. These things can’t go out in a blizzard for a 20 mile run (like Mark D. and I did a while ago), or race in torrential downpours (like Tiffany, Dale, and I did for Ironman USA 2008). If you need inspiration, remember, I’m out there doing these things, and if you’re not, that’s just one less person I have to worry about racing against. Enjoy!

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