In order to be a consistent runner, and a consistent runner is typically the one who gets faster, it is important to stay on top of the choices you make - the key being not making training/racing errors. And when I see runners frequently determine their goal racing paces based on training paces and/or training paces based on goal racing paces, it makes me want to jump in and say something. You see, it simply doesn't work that way. If you're lucky, you don't hurt yourself. Conversely, you can dig yourself quite the hole.
Let's look at both ways people go about this process and why it doesn't work, and then talk about how you can determine your paces in both training and in racing.
Determining Goal Pace Based on Training Results
Simply put, training is exactly that - a means to an end to get your body prepared to race. The vast majority (approx 80%) of your weekly training should consist of easy running. So there should be no reason why you'd be able to tell from your training results that you are ready to run at a given pace. Some people however utilize different training protocols (think quality over quantity), so your experience may seem to differ in terms of the amount of easy running you do. Either way, running 80 miles/week of quantity isn't going to tell you anything more than 30/miles of quality. It just means that those 30 miles probably have a lot more "work" as a percentage of the total volume in the week. But at the end of the day, they both produce a stimulus and your body responds by (hopefully) getting more fitness.
Aside from a handful of workouts one can do to simulate a race, no amount of results in training will typically help you determine your paces. Now that said, that doesn't mean those simulation workouts don't have value. Those are critical workouts one SHOULD do at KEY times to determine if your potential goal paces are in line with your fitness. However, simulation workouts need only be executed 1-2 times in a whole training cycle, and not more frequently. They don't give you the fitness gains you seek from training, so while they serve the point of helping you determine if you are race ready (physically and mentally), they don't necessarily make you more fit. Specifically in the case of marathon training, running marathon pace is too slow to give you big fitness gains and too fast to serve the same purpose of your long runs of teaching your body to become more efficient at burning fat. That is why you should save those marathon paced miles for as you approach race day in the last month or so of training and not many months out. Simulation workouts need to be scheduled at strategic times, so they don't take away from the quality work you could be doing to give you big fitness gains early on. Otherwise, you should be training at your training paces.
Determining Training Paces Based on Goal Racing Paces
Let's say you ran a 4:15 marathon last year and now you really want to run a sub-4, so you arbitrarily say you are going to train at 4 hr marathon paces. You go onto the McMillan calculator and out spits your paces and off you go training. This happens time after time and despite many attempts to inform others that it doesn't work like this, it seems the concept of arbitrarily determining one's paces is more popular than ever. Even though one might surmise that someone who ran a 4:15 could improve to run a sub-4 with solid training, you simply can't just change your paces and hope things work. Your body doesn't work like that, especially when we talk about the marathon. The specificity of requiring your body to utilize fat as fuel is the key here. Below are the 2 sets of paces for reference:
Now, the first thing I'll note is that the Long Run Pace provides a difference of about 30s/mile. For most people, this difference will not prevent someone from hitting those paces. But more specifically, you'll see that those pace ranges overlap quite a bit due to the very large pace range provided by the calculator (Quick aside - One of the problems I have with the McMillan calculator for use is that even at 3:45 marathoner still has a range that overlaps with the 4:15 marathoner. I strongly recommend checking multiple calculators and taking an average, not just from a single source because they all use different algorithms.) So while this person might be able to run 9:45/mile for their long runs, it doesn't mean they are ready to run a 4 hr (or a 3:45) marathon. But most commonly, they will be lulled into the false sense that they can. For many people, the long run is THE key run of the week. So long as they get this run done on pace, it seems their marathon training is on track. But the reality is there are so many other elements, more specifically total weekly work to include both volume AND intensity. Simply running all your long runs at 9:45/mile isn't going to prepare you to run a marathon at the required 9:10/mile pace for a 4 hr marathon. All that other stuff matters too.
Now let's take a look at another element of running calculators that many overlook in this process - predicted race times. At the top of each example above, you'll see the equivalent performances at various distances. So for the 4:15 marathoner, they likely can run a 54:21 10k, while the 4:00 marathoner can likely run a 51:09. Here is where the math rarely adds up for those who select their training/goal paces. Did the 4:15 marathoner drop 3+ minutes from their 10k (or any other equivalent distance) in order to justify the change in paces? Probably not. Now realize, that some people run faster at longer distances than shorter ones. So while there may be a discrepancy between a runner's 10k time and their marathon time, most commonly, runners perform better at shorter distances in these prediction tools than they do at longer ones. Even still, for that 15 minute bump down in goal time, I'd expect someone to be able to run a 10k closer than 3:00 of what the calculator might predict.
How to Properly Identify Your Goal Paces
So now that we agree that both methods simply don't give someone an accurate picture of what their goal paces are, what is one to do to make sense of this all? Well, it comes down to the planning and laying out of the training period to make sure one incorporates races and/or time trials to "prove" their fitness. Want to run faster than your current paces? Prove it by running an equivalent time faster than you currently are slotted at and then you can adjust your training paces and race expectations. For the marathon, you have several options that I'd recommend:
- 5k time trial - 5ks serve as the perfect fitness indicator. Short enough that they don't take away from your weekly marathon training, but long enough that you are less likely to be able to fake your fitness like you can in shorter time trials like 1 mile, Yasso 800s, or less. While there is going to be a difference between what goal pace you should predict for the marathon simply due to the fact that most runners perform better at shorter distances, I use 5k time trials early in the training period to prove my fitness and adjust paces based on my performance.
- 10k time trial - 10ks also serve as a useful measuring stick for marathoners, since they give a slightly better indication of ones fitness for the marathon than the 5k does. The 10k may take an extra day or so of recovery from an all out effort, but it can be a useful tool in the same way the 5k is - to predict training paces and prove fitness improvements. I like to schedule a 10k in the middle of the marathon build, after a few 5ks have been done. This can help validate or give someone food for thought if any training adjustments might be necessary to meet a goal.
- Half marathon - The half marathon is going to give a marathoner the best indicator of a prediction time, as it is the longest distance race I'd recommend before a marathon. Anything longer raced hard and you seriously risk compromising valuable training time. A hard fought half marathon, may take up to a week to recover from, but I find I can get back into the groove after 3-4 days of easy running. While still never a definite predictor of marathon performance, you are less likely to deviate too far from your marathon prediction. I like to put a half marathon in there 4-6 weeks out from the race. By this point, you are far enough out that any issues can still be resolved, but not so close to the race that you compromise carrying fatigue into the race.
So those are the methods I recommend runners use to identify your goal paces. Convinced you're faster than your predictions say? Go out and prove it the right way!