Does Distance Running Really Harm You?

 

I love it when new data challenges the conventional wisdom. And a truism that is often perpetuated without interrogation is that long distance running, particularly on the road, causes osteoarthritis of the knees, hips and possibly degeneration of the lumbar discs. 

But is there any data to support these assertions? I have spent years observing this trend with interest, back when we were based in Manchester City Centre I helped with some biomechanical assessments at a local running shop which was part of a big national chain.  I quickly noted they had a rather poorly-evidenced but effective selling technique:

You turn up for a pair of new running shoes and are assessed on the running machine. This films only your foot motion, not your pelvic motion, not your torso movement and not the shoulders with which most deconditioned wannabe runners actually run!  Your foot ‘turns in’ or pronates on the film and the sales guy make a big deal of this. (NOTE: EVERYBODY pronates to some degree as they move to the weight-bearing phase of the gait cycle regardless of rear or mid foot strike4, so therefore EVERYBODY who was filmed had a foot that ‘turned in’.)  Apparently, according to the sales guy you therefore needed the expensive anti-pronatory shoe which would solve all your problems but costs twice as much as any other shoe in the shop.

So given that a little science has actually now begun to appear among a lot of dogma, I decided to do a review of the main scientific findings:

A review by Cymet and Sinkov in the Journal of the American Osteopathic Association1 highlights the lack of evidence to suggest that running is bad for your joints. Indeed, they suggest that, “the preponderance of data seems to indicate that moderate levels of running do not increase the risk of osteoarthritis of the knees and hips for healthy people and that this activity might even have a protective effect. 

While this might sound somewhat contrary, it should be no surprise that connective tissues undergo a reactive hypertrophy (growth) when they are exposed to long-term repetitive loading, including articular cartilage (joint lining). Chakravarty2, after studying a group of runners over two decades, stated that, “Data suggest that long-distance running may not be associated with increased progression of knee OA in the absence of knee injury, obesity, proprioceptive (sensory feedback) deficit, or poor muscle tone.” 

But what about other supposed running-related injuries such as calcaneal (heel) spurs, Achilles tendinopathy or plantar fasciitis (pain in the sole of the foot)? 

There is a growing body of evidence to suggest that the rise of lower limb overuse injuries has paralleled so-called ‘advances’ in the design of running shoes. Prior to the 1970’s, and for most of our history, runners have either proceeded barefoot or used minimal footwear. But after the advent of the padded running shoe there has been a proportional rise in lower extremity injuries.

According to Richards et al3“The use of cushioning in running shoes is based on the following assumptions:

  1. That impact forces while running are a significant cause of injury.
  2. That running on hard surfaces is a cause of high impact forces.
  3. That a cushioned shoe can reduce impact forces to a less injurious level.
  4. That the potential of the cushioning itself to cause injury is minimal.

However, the evidence for this is very limited and certainly the prescription of modern running shoes is not ‘evidence-based’. Remember my experience in the Manchester Running shop?

Unfortunately, thinking about running shoes over the past 40 years seems to have promoted an arms race, with the development of ever greater shoe complexity, but new thinking suggests that we have designed ourselves into a biomechanical corner. 

In essence, the evidence suggests that our biologically normal running style has transformed from a predominantly fore-foot strike (or mid-foot strike) to a heel strike. And landing heavily upon your heel is not what nature intended, no matter how well padded it might be. Not only does landing upon your heel create greater impact forces upon the lower limb, the force actually increases with the amount of shoe padding provided. 

As paradoxical as it sounds, there is now a growing consensus between biomechanists that the modern running shoe may well be the cause of many of our problems, as they increase ground reaction forces, limit proprioception (sensory feedback), weaken the intrinsic muscles of the foot and reduce arch strength. This seems especially so for the PCECH (pronation control, elevated cushion heel) models.

Harvard professor Daniel Lieberman4 has embraced his research findings by putting his money where his mouth is and taken up barefoot running. Take a look at the video below from the journal Nature.

But what about the intervertebral disc of the lumbar spine? 

It is understood that loading of the spine can promote disc degeneration in some circumstances, but the characteristics of such loading are not well defined. There is no evidence that running accelerates disc damage, but there is some recent data to suggest that it might be capable of stimulating matrix (the disc is made from various substances such as proteins and collagen) production within the disc and possibly strengthening it. 

It has been shown that dynamic loading of a disc produces anabolic (growth) effects, whereas static loading has a catabolic (decline) effect. Indeed, a recent paper in the journal SPINE examined rats that ran on a treadmill and noted that the intervertebral disc demonstrated an increase in cellularity and an increase in the expression of collagen, aggrecan and proteoglycan5, possibly suggesting that there might be some long-term benefits to this type of dynamic loading. Given also that running has been shown to increase neurogenesis (new growth), learning and long-term potentiation (and therefore memory) in mice6, we can see that preconceived notions of distance running being “bad for you” may well be misplaced.

References:

1. Cymet TC, Sinkov V. Does Long-Distance Running Cause Osteoarthritis? J Am Osteopath Assoc. 2006;106:342–345
2. Chakravarty EF, Hubert HB, Lingala VB, Zatarain E, Fries JF. Long Distance Running and Knee Osteoarthritis – A Prospective Study. Am J Prev Med 2008;35(2):133–138
3. Richards CE, Magin PJ, Callister R. Is your prescription of distance running shoes evidence-based? Br J Sports Med 2009;43:159–162.
4. Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, Ojiambo Mang’Eni R, Pitsiladis Y. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature. 2010; 463 (28): 531-535
5. Brisby H, Wei AQ, Molloy T, Chung SA, Murrell GA, Diwan AD. The Effect of Running Exercise on Intervertebral Disc Extracellular Matrix Production in a Rat Model. SPINE 2010; 35 (15): pp 1429 –1436
6. van Praag H, Christie BR, Sejnowski TJ, Gage FH. Running enhances neurogenesis, learning, and long-term potentiation in mice. PNAS 1999; 96 (23): 13427–13431

Comments are closed.