Are You at a Higher Risk for Running Injuries? The Latest Research on Who Gets Injured and Why

In our previous injury prevention articles, we’ve examined risk factors or preventive strategies for specific injuries, or types of injuries.

Hip strength, for example, looks as if it prevents knee injuries, but there’s less evidence that it prevents foot injuries. And increasing your stride frequency might protect you from injuries associated with hitting the ground too hard, but not all injuries share this risk factor.

Today, we’re going to look at the big picture: we’ll examine which runners get injured and perhaps find some reasons why.

There are relatively few studies that examine running injuries in general, probably because of the difficulty of carrying out such studies. To get an accurate picture of the general running population, you need thousands of subjects in your study. Additionally, you have to follow them over a long period of time, or at least use surveys that ask the runners to recall their training history, injury history, and so on. Finally, you have to define what constitutes an “injury”! Fortunately for us, a few researchers over the years have undertaken such efforts, and we’ll examine two studies which took two different approaches to illuminating who gets injured and why.

Study on risk factors for injury

The first is a 1987 study by Bernard Marti and coworkers at the University of Bern in Switzerland.1 Marti et al. interviewed 4,358 male participants in a popular ten-mile road race, asking the runners to fill out a detailed history of their previous year of training. Mileage, shoe choice, height, weight, age, years of training, and many other factors were examined.

Right off the bat, Marti et al. found that 55% of these runners had suffered no injuries in the previous year. The other 45% had suffered an injury—but only about half of these injuries were serious enough to require a runner to actually curtail his training; the rest we might classify as “aches and pains.” This highlights one of the problems with these large-scale injury studies: what constitutes an injury? Simply something that hurts when you run? Or does it have to be more serious?

To get around this problem, Marti et al. constructed a tiered classification system, based on the duration of symptoms and their severity. About half of all injuries were “Tier I,” or minor injuries that did not lead to a significant interruption of training. The other half were “Tier II” and “Tier III,” moderate to severe injuries which required breaks from running. Remember that all of the runners in this study were healthy at the time of the survey, or at least healthy enough to complete a ten mile race!

Mileage is associated with increased injury risk

Moving on to risk factors for injury, Marti et al. found that mileage was significantly associated with injury risk. This is in line with several other studies which have connected a higher running volume with an increased risk of injury. However, two interesting phenomena were observed in this particular study.

  • First, the risk related to running mileage seemed to “top out” at between 40 and 60km a week (25-37mi/wk), at least for this group. Runners above this mileage did not seem to gain additional injury risk.
  • Second, increasing mileage at any level reduced the incidence of injury when expressed in injuries per 1000km run. So, paradoxically, it seems that higher mileage runners cover more ground at a lower risk per mile, but that’s offset by their higher overall volume (to a point, at least).
  • Additionally, age and years spent in training had a protective effect for many injuries. The younger you are, and the less training experience you have, the higher your injury risk. Two exceptions to this were found: older runners were found to have a higher risk of calf and Achilles injuries, and a somewhat longer recovery period.

Other risk factors that influence injury rate

Among the other factors examined, having a history of injury and being a competitive runner were also risk factors for injury, which should come as no surprise. However, if you control for mileage, competitiveness is not as “risky”—the higher incidence of injury in competitive runners seems to be a function of the fact that they run higher mileage.

And with respect to weight, there seems to be a U-shaped curve of injury risk. Only people at the extremes (the severely overweight and the truly underweight) were a higher risk for injury. So if you’re still carrying a bit of “winter insulation,” it shouldn’t increase your injury risk.

Finally, shoe choice and running surface had no effect on injury. Runners with less “brand loyalty” (and who presumably swap shoes more often) actually had a somewhat lower incidence of injury, perhaps indicating that switching up your shoes might be a good idea.

Newer studies on running injury risk factors

Marti’s study is almost twenty five years old. A lot has changed since then, especially surrounding shoes and participation, so we ought to look at data from a more recent study too.

Fortunately, J.E. Taunton and his colleagues at the University of British Columbia carried out another large scale study of injuries in runners which was published in 2002.2 Unlike Marti’s study, Taunton et al. examined only runners who had come to a medical clinic because of an injury. As a result, all 2,000 of the participants in Taunton et al.’s study had what Marti would have called a “Tier II” or higher injury. Only about a third of the injuries in Marti et al. were serious enough to merit seeing a doctor, so we’re getting a cross-section of the more serious injuries in this study. Additionally, there was no control group, so the findings here are not as strong as those of Marti et al.

Risk factors include mileage, competitiveness, age, and years training

Regardless, many of the risk factors identified in Marti et al. were confirmed by Taunton et al. These include:

  • Running higher mileage
  • Being a competitive runner and serious focus in training
  • Being younger than 34 years old
  • Being active for less than about eight and a half years

Additionally, as Taunton et al. examined both men and women, they were able to show that women outnumbed men at their clinic, accounting for 54% of their patients. Specific injuries like patellofemoral pain, IT band syndrome, and hip or shin injuries were significantly more common in women, whereas tendon injuries to the Achilles and patellar tendons were more common in men. In women, having a BMI below 21 was also a risk factor for some types of injuries, especially stress fractures.

Unlike the trend for injuries in general, Achilles injuries were more common in runners over 34, in line with Marti’s findings fifteen years earlier. The Achilles and calf may weaken over time in older runners, or biomechanical factors may shift more stress onto the lower leg over time as you age. In all runners, the most common injuries were around the knee and foot: patellofemoral pain and IT band syndrome, followed by arch pain in the foot (plantar fasciitis).

So, are you likely to get injured?

Large scale studies like the ones we’ve seen today are not the most helpful tool in figuring out the causes of injuries, but they do help us look at the big picture. Who gets injured?

From Marti et al. and Taunton et al., we now have a better idea: younger, less experienced runners who do higher mileage and train to compete are at a higher risk, especially women.

But the good news is that the longer you spend training, the lower your injury risk becomes, and the risk of additional injuries at higher mileages seems to flatten off around 30 miles a week or so.

Though your overall risk of injury decreases as you approach Master’s-age, your risk of Achilles and calf injuries increases, so do take care when doing high-speed training or uphill running if you are in your mid-thirties or older.

Women should watch out for knee, hip, and shin problems more carefully, while men should keep an eye on their patellar and Achilles tendons.

In any case, no matter who you are, you shouldn’t let the risk of injury hold you back. You can incorporate a running-specific strength routine to help ward off injuries. Plus, the longer you stick at it, the better your chances are of staying healthy—that’s good news for everyone!

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References

1. Marti, B.; Vader, J. P.; Minder, C. E.; Abelin, T., On the epidemiology of running injuries-the 1984 Bern Grand-Prix study. The American Journal of Sports Medicine 1988, 16 (3), 285-294.
2. Taunton, J.; Ryan, M.; Clement, D.; McKenzie, D.; Lloyd-Smith, D.; Zumbo, B., A retrospective case-control analysis of 2002 running injuries. British Journal of Sports Medicine 2002, 36, 95-101.

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4 Responses on “Are You at a Higher Risk for Running Injuries? The Latest Research on Who Gets Injured and Why

  1. Thank you for the thorough summary of these benchmark studies. On the mileage versus injury risk question, you may be leaping from correlation to causation, whether intentionally or not, when you discuss the “U-shaped” nature of the injury risk versus mileage curve and the reduction in injury risk with increased years of running. Perhaps runners who are less injury prone are better able to handle high mileage (and those that aren’t get “weeded out” as they increase their mileage), and better able to run continuously for the 8+ years that you site. The authors of the studies seem to be more careful in discussion “association” between mileage and injuries instead of making any conclusions regarding mileage increases “causing” or reducing the incidence of injury.

  2. That’s a good point, Greg. It’s very possible that injury-prone runners simply don’t make it for more than a few years! But I do suspect there is a protective effect that comes with continued training over time. The military funds a ton of studies on overuse injuries and their causes, and one of the most consistent findings in new military recruits is that the recruits with little or no previous history of training (whether in sports, for fitness, etc.) get injured during basic training at a much higher rate than the recruits who had been active before joining the military. Of course, getting injured increases your risk of future injury too, so there’s got to be a balance between maintaining your training over a long period to adapt your body to the stresses of running and staying healthy at the same time. Thanks for the comments!

    —John

  3. Thank you for the information. I have been running or jogging for the last couple of years and have just recently decided to train for a marathon. It worries me being 53 and never actually running competitively that many articles I read about preventing injuries uses 35 as the starting point of getting older and being injury prone. In the last month I have increased my mileage from 10 miles a week to 20 plus and lowered my times from 10 minutes per mile to 9 minutes per mile. The tendon on my right ankle has been hurting but has eased off somewhat. As you know many shoe companies and runners claim their shoe will cure all ailments. Where can I go to get empirical information about running for fifty year old geezers that gear toward my needs?

  4. I’m a 41 year old women who started running two years ago and have had a tibial stress fracture. Since I have been back running regularly again I have insertional Achilles tendonitis and now I think my stress fracture is back and I’m only at 10 miles a week. I think I am one of those injury prone people.

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