Running more miles relates to faster races for some, but not more injuries

Following twitter I often read arm chair experts draw erroneous conclusions on many studies, so I was not surprised to read world-renowned armchair physiologist Alan Couzans conclude that a recent study by Fokkema et al. supported the notion that high volume is the secret to fast performance. Why? Because Alan’s entire philosophy of being is built around volume is king to the point that he’s all but created data out of whole cloth to support that premise. Now if you’re a fan of Alan, don’t worry, this article is about what the Fokkema paper actually showed, rather what Alan wanted everyone to believe.

What was Fokkema all about?

Published in the Scandinavian Journal of Medicine and Science in Sports, the authors sought to: :

“…to examine the associations of training volume and longest endurance run with (half-)marathon performance and [run-related injuries] in recreational runners participating in a half marathon or marathon.”

They studied 997 participants in two specific races, a 1/2 (556) or full (441) marathon, and collected survey data on several aspects, including training and injury history; ~2/3’s were male and subjects averaged about 42 yo. For full details on all the data and how they parsed out training variables please checkout the full paper, which is loaded with great data. For my purposes, I’m focusing on two main aspects, running volume on performance, and injury risk.D

The Age Old Question: Is more better?

The short answer to that question is yes, but its more complicated than just training endless hours; in this respect we already know this. What is most interesting is that the weekly threshold for the 1/2 Marathon (1/2) is >32 km (20 miles), while the marathon (M) was >65 km (40 miles). Its unclear where the point of diminishing returns is, but neither of those mileages is terribly high. Another point to note is that there appears to be a minimum mileage needed for a decent M, at about 25 miles per week; runners doing less ran much slower. So let’s breakdown a bit more.

Physiologically speaking, it makes sense that the marathon is more impacted (NPI) than the 1/2. Anyone experience with running a 1/2 knows it doesn’t take a lot of training to run a pretty good 1/2, but a good M on 20 miles a week probably won’t be enjoyable, or fast. This paper largely confirms this, showing that higher volumes of training likely has important downstream training effects on fatigue resistance and resilience. But the details matter too! If we look at two of the figures (Red circles identify the fastest runners) from the paper we see some very interesting things:

  1. Most of the fastest 1/2 trained 70 km or less, and M runners trained 100 km or less, and the two extreme outliers were not the fastest; the fastest 1/2 was <60 km/week.
  2. When we look at all the runners like this we don’t actually see the clear MORE IS BETTER relationship. In fact, what we see is most runners cluster around the lower mileages.
  3. Conclusions from 1 and 2 actually suggest that there is a certain optimal range where best race performances occur.
  4. One major caveat though, is that cluster of fast 1/2 and M runners doing less than 50 km/week and performing well!

Go long to go fast…just not too long!

Possibly a more important finding of this paper was underscoring the importance of the long run in training. As we look at the figures below the important aspect I note are:

  1. Regardless of the race distance, 40 km (25 miles) seems to be the upper limit for either group and the a long run of at least ; i.e., huge long runs don’t help.
  2. The fastest 1/2 runners (<90-min) all did long runs of at least 20 km, and the overall trend was for long runs of greater than 21 km, but less than 40 km. The trend of the data was longer was associated with faster.
  3. All the fastest marathon runners (those closest to 3-hrs or less) did long runs between 25 and 40 km. The trend was more a clustering around runs of 30+ km.
  4. Conclusions from 1 – 3 suggest that long runs matter, particularly if you want to run fastest. In my opinion, assuming your hitting the minimum training treshold, I would rate the long run more impactful than overall volume.

Speed still matters!

One brief note worth mentioning is that both groups spent 20-25% of their training time doing intervals. Another even more pertinent finding is that runners should not confuse training volume with long slow miles. While easy training miles are an important aspect to training (see polarized training), faster racers are faster trainers. In both groups, runners whose average pace was <5:15 min/km (~8:20/mile) were on average 14-min faster in the 1/2 and a whopping 34-min faster in M! Moreover, those training slower than 6 min/km (9:40/mile) were 13 and 31-min slower, respectively, than those training 5:15 – 6:00. Again, there are lots of ways to slice that, but in simplest terms, if all you do is train slow, expect to race slow.

But what about running injuries?

This summary is easy! It turns out (not too surprisingly) that training mileage is not really related to injuries. Not surprising at all, the leading factor for an injury was a prior injury; this is actually well established. Still, one would expect that if you train more (e.g., over training) you risk greater injury, and there is truth to that. But as any good running coach already knows, and prior research has supported, mileage is an easy but relatively poor way to prescribe or track training. One of the main reasons goes back to prior point on running pace in training. If many faster runners train more miles, but they cover those miles in less time, their actual training time and ground impacts might be similar. In fact, another recent paper by Paquette and colleagues noted how slower runners can exhibit higher external loads stating:

Running distance alone might vastly obscure the cumulative training stress on different training days and, ultimately, misrepresent overall training stress.”

Conclusions

As I stated at the beginning, this article was less about criticizing Alan Couzans’ obvious misinterpretation of the data here and more about what it really showed. I hope its clear that more volume is not the answer to faster running. While I’ve summarized each set of conclusions above, some might be asking, What should I do? First, if you are a low mile runner (like me), you can still perform well, especially if you 1) include a few hard long runs of 20 – 30 km, and 2) be sure you’re putting in some good quality (fast) miles. My advice is to structure training volume and intensity appropriately, rather than simply piling miles on in the hopes of running faster. However, if you have tried many training programs EXCEPT more training time, consider trying to add at least a few more high volume weeks. Finally, running injury etiology is complex. Running more may lead to injury, but that previous injury is more likely to lead to injury.

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