In 2013, Runner’s World published a piece by Amby Burfoot that concluded most runners are better off listening to their bodies versus following a formulaic pacing approach, according to a study he cites.
Amby reviews the marathon data and writes…
The runners held their pace for 13.1 miles, but then slowed dramatically. But wait. We all know The Wall doesn’t hit you until 20 miles. There’s no physiological reasons for marathoners to suddenly fatigue at the halfway point. What gives? Why did the runners crash at 13.1 miles?
My guess: The runners were relying too heavily on high goal-setting, heart-rate monitors, GPS systems, equivalent-performance tables, and the like. In other words, they used one or several of these tools to pick a goal pace faster than their actual race-day fitness. That’s what we high-success, high-determination, Type A runners often do.
We agree and want to ensure that the purpose, intent and best use of the VDOT Calculator is clearly understood, rather than contribute to a misguided pacing strategy.
Equivalent Performance Does Not Equal Race Predictor
As Burfoot mentions, equivalent-performance tables, which Jack first popularized in his book – Daniels’ Running Formula – are commonly used to gauge how fast you should run in upcoming races of varying distances. It’s critical to note that the key limiting factor in the VDOT equivalent-performance table is that it doesn’t factor in your training background. It’s not a straight predictor. The table is a great tool to help get you in the ballpark as to what you could run for other distances, but one has to consider their individual training history, especially when it comes to the marathon.
One of the great advantages of the VDOT equivalent performance table is that it can help you identify what areas of your training are preventing you from reaching the same performance level at a different distance. For instance, you can run 1:46:27 for a half marathon but can’t crack 3:55 in the marathon. Is it the marathon course/weather, or your 30 miles per week that are keeping you from running the equivalent performance of 3:40:40? Are you not getting in enough work at threshold or marathon pace?
We’ve never been in the crystal ball business. Our calculator can’t predict what one will run in any distance, particularly a distance as complicated as the marathon, because there are a myriad of factors to include in that equation. VDOT doesn’t know if your goal race is in 90 degree weather or the course is straight uphill. Obviously, you have to adjust for these factors. It also doesn’t know that you are only running 25 miles per week on three runs per week or that you’ve never run a marathon before.
Once upon a time, no one ran slower than 3-hours in the marathon before it became a mainstream phenomenon. Those who trained for marathons typically ran at least 80 miles per week and would more likely be able to hit the equivalent performance of their half marathon in the marathon. The challenge of the marathon is that the distance can dramatically throw off your pace in the last 10k if you’re not prepared or the conditions are off by just a few degrees.
Another trend with greater participation in marathons is runners toeing the starting line completely unprepared. Organizations are attempting to capitalize on the revenue potential of this mass participation by inducing people to use inadequate training plans, and then compound these mistakes by misusing a calculator and trying to run a pace based on the false hope they’ve been given in their training.
We rarely advocate that one has to run 80 miles per week in order to avoid the wall, or be responsibly prepared for the marathon. It really depends on your background and goal. For instance, 5-hour+ marathoners we encourage a run-walk approach and keeping long runs short while incorporating Jack’s patented “bunched long runs”. It comes down to preparing individually for a 26.2 mile race and adjusting on race day when you have to go that extra distance off of an amateur weekly mileage resume.
Remember, if you only run 25 miles per week you may be able to train at a specific pace and do 10 mile marathon pace sessions comfortably but that doesn’t mean you can run that pace for 26.2. At 13.1 miles you can sometimes get away with 25 miles a week and holding the equivalent marathon performance of your 10k. But when you plan to run 26.2 you have to adjust your goal pace. We see more clients race 26.2 miles at the VDOT pace they trained at when they were consistently in the 45-55 miles per week range at minimum.
There’s not a perfect formula when it comes to predicting marathon outcomes and that’s where experience or a coach comes in. If you’re a lower mileage runner (25-35 mpw) and you’ve been consistent in your marathon training in many cases we suggest racing at about one to two VDOT points lower than what you were able to manage in training. This obviously depends on a lot of factors that we consider when reviewing your training. If you have questions before your next race please don’t hesitate to email us.