A new method to predict marathon race times with wanderings and wonderings about base versus interval training

Prediction of running performance is nothing short of an intriguing concept. Everybody wants to know what they are capable of achieving, according to internet math, even if they don’t actually pull it off in real life. Predictive measures have been used to obtain expected race times for multiple decades, and I would like to think they are more accurate now than in the 1970s. There is nothing like a true performance at a specific distance to guide your training and racing. But for a beginner or someone that has done just a handful of events, a race predictor can be really helpful to determine appropriate pacing.

I recently came across an article on a new marathon time prediction method that can be found here. The calculator is found here. It is based on research by the same author, available at this page. The researchers used my favorite statistical method, regression analysis, to create a prediction model for amateur runners, based on amateur data. This differs from previous predictors which were largely created from the performances of elite runners.

Runner’s World recently updated their predictor to this same format because it tends to generate a slower time than other predictions would develop. Why is that important? To keep you from blowing up badly, particularly if you are mid-pack or slower runner.

The nice thing about this specific calculator is the fact that it considers your average weekly mileage in the equation. This lets you see where training can play a role. You can really ask yourself if that extra 10 miles per week is worth it when the gain is just one minute over the course of an entire marathon.

For some, of course, the answer is “yes.” But for others that extra 10 miles each week can result in frustrating injuries that could keep them from training and racing altogether. And maybe during that 10 miles you would rather be playing with one of your kids. There is also research to indicate a lessening health benefit of higher mileages (http://www.mayoclinicproceedings.org/article/S0025-6196(16)00068-9/fulltext). The predictor provides a nice method to weigh the diminishing levels of improved performance with the benefits of health and sanity.

This had me thinking, it would be interesting to see how training type plays a role in the goal performance for a given individual. In other words, do you gain more improvement from a focus on long, base runs, or on high-intensity interval work? The average marathon training program is going to include both, because they work different metabolic systems, but I would be curious to know which is more critical for a given person. Sometimes it is obvious, sometimes not.

Let’s say you want to run a 3:30 marathon on 25 miles per week but the predictor expects you to do a 3:35. Is there a certain type, frequency, or amount of anaerobic training that could make up the difference while keeping the mileage that low? Maybe that’s not reasonable and it really comes down to making sure you get in increased mileage to gain that five minutes.

It will undoubtedly vary depending on training history and genetics. The Crossfit nation would try to make us believe that it’s all about the interval training. I would argue that lack of familiarity with longer distances weighs more heavily in a new runner than any amount of anaerobic ability gained with high-intensity intervals. Once you have some base training and long racing experience, then feel free to focus on both or just on harder intervals. I venture a guess that intervals and tempo efforts gain fitness for many people simply because they haven’t stressed themselves in that specific manner. That fitness won’t help much if you mentally crack at mile 23 because it’s all new territory.

To think you can do a marathon well and only do long runs of six or eight miles seems like a recipe for disaster in the uninitiated, though. For a 5K or 10K race, I suspect that many amateurs could rely heavily on interval training two to three times each week for multiple weeks in a row and never once do continual easy or moderate paced runs. Yes, it would still be useful to at least occasionally cycle through weeks of longer, slower base training to stress the aerobic physiology. It is not common to fluctuate training this dramatically, though. Yeah, the mileages would be all over the place. I may have to use myself as a test subject. Maybe it’s a little different way to consider “polarized training.” If nothing else, it is a definite change of pace.

The variation of training stimulus could keep injury rates lower yet continue to change fitness. I recall reading a research article many years ago indicating performance gains in elite level endurance athletes because they essentially doubled their base aerobic training time. These are athletes that are already at the top of their game but they swung the training pendulum one direction and changed their program so dramatically that it helped get them through a plateau. This can clearly work both directions.

My only concern is to be cautious of injuries. Hyper-volume training is surely a recipe for overuse injuries. Too much interval work could be a problem too, especially if you were trying to keep overall weekly mileage high, if your interval running technique was drastically different than your normal slow technique, or if your muscles and tendons were just not up to either task because of strength deficits (a.k.a. start strength training in any case).

Send questions and comments to derek@mountainridgept.com.