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Cover Less Ground: The Key to Faster & Injury Free Running

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 “Running over 30 miles a week for probably my first five or six years on Tour pretty much destroyed my body and my knees.”  -Tiger Woods

 

With an injury rate as high as 92%, it comes as no surprise that Tiger Woods recently claimed running destroyed his body (runningmagazine).

While that is likely untrue -- it was most likely how he ran that did.

Running performance is typically measured by distance and speed. How much ground you can cover in a certain time. But the recipe for injury-free running is not how much ground you cover, rather how much ground you don’t cover. 

 

Why It Matters

Two small perhaps overlooked changes to your running method not only drastically reduce injury risk -- but will actually make you faster in the process. 

 

Key Takeaways

  • The part of your foot that hits the ground determines where you are likely to get injured.
  • Heel landing (“rearfoot strike”) tends to affect the knees;  whereas front-of-foot landing (“forefoot strike”) tends to affect the Achilles and calf. 
  • Increasing your flight time (time off the ground completely) and cadence (steps per minute; a running “RPM”), will reduce your risk of injury and make you faster. 

 

In 2017, an estimated 55.9 million Americans participated in running, jogging or trail running. (14) A national running survey of the same year conducted by Running USA found that 75% of runners had reported to have had a running related injury. These findings are consistent with previous studies of running injuries, with rates ranging as high as 92%. (15, 16) 

 

Here’s what Tiger and the 42 million injured runners should have known.

 

 

Running Mechanics

To improve your running, the first thing you need to know is what actually happens as you are doing it.

Each time you take a leg through a full range of motion propelling you forward while running, is called a gait cycle. 

The portion of the gait cycle where the foot makes contact with the ground (or treadmill) is called the foot strike.

The primary foot strike patterns for running have been described as: 

  • Rearfoot striking. Initial contact with the ground occurs at the heel/posterior region of the foot.
  • Midfoot striking. The posterior and anterior portions of the foot simultaneously contact the ground.
  • Forefoot striking. The anterior region of the foot strikes the ground first.   

 

Because they determine how much force, and where that force is transmitted in the body, foot strike patterns have long been the focus of running research, for both speed and injury-reduction.1 

 

Research suggests that as much as 89% of runners are rearfoot striking. (1) 

However, a large body of research has identified forefoot striking -- not  rearfoot -- as the ‘natural’ foot strike of our barefooted ancestors. 

 

This suggests that sneakers, with cushioned soles that are usually thickest at the heel, have fundamentally changed the way humans are supposed to run.9 

 

 

How Does Running Speed Affect My Foot Strike?

In addition to sneakers, running speed influences the foot strike pattern.  

When speed is increased, nearly half of runners switch to a more forefoot dominant strike pattern.4 The change to a forefoot strike is likely what allows sprinters and middle-distance runners to attain faster speeds. (3)

That said, a forefoot strike is less sustainable. So much so that the majority of forefoot-striking marathon runners switch back to an rearfoot strike by the end of the race. (8) 

 

Could Changing Foot Strike Affect My Risk of Running-related Injuries?

So far, we have established fundamentals behind foot strike and its relationship to both  speed and where force is transmitted in the body: 

  • Sneaker cushioning and your running speed will influence the way your foot makes contact with the ground; forefoot, midfoot, or rearfoot. 
  • The way your foot makes contact with the ground determines where the force of impact travels in your body. 
  • Where the force of impact travels in your body is where you are likely to be injured. 

Knowing this, could changing foot strike reduce your risk of getting injured? Yes. In fact, changing foot strike pattern has shown promising results for injured runners -- especially those with knee pain and Achilles/calf pain. (13, 7)

 

 

Running-related Knee Pain

Have you ever been told you have “Patellofemoral Syndrome” (PFS)? This relates to the structure of the knee -- the patella, or kneecap. It is more or less a blanket term, of excruciatingly little diagnostic value, that means “your knee hurts.”

Most often, runners receive this pseudo-diagnosis and are told to simply take time off from running for the condition to heal. It should not be surprising that while not running the knee pain magically disappears. The problem, and if you are a frequent or serious runner you know this to be true, is that the knee pain nearly always returns.

There are several factors that can contribute to knee pain and Patellofemoral Syndrome, including lack of appropriate mobility and stability from the ankle all the way up through the hip to the torso.

Rearfoot strike running patterns seem to cause increased patellofemoral loading (stress on the knee) which has the potential for an increased risk of knee pain, specifically pain in the front of the knee. 

Rearfoot strikers’ experiencing knee pain may benefit from adopting a forefoot or midfoot strike pattern. (11)

 

 

Running-related Achilles & Calf Pain

On the other hand, or rather other foot, a forefoot strike pattern can increase ankle plantarflexion (foot position you employ when you hit the brakes), as well as Achilles tendon and/or calf loading — all of which could raise the risk of  Achilles’ tendon, calf and ankle/foot injuries.7 

This suggests that runners experiencing Achilles’ tendon and ankle/foot pain may benefit from adopting a rearfoot or midfoot strike pattern.

Caution - In some cases, simply modifying your foot strike pattern may cause you to switch out one problem for another! 

 

Cadence - A Magic Bullet?

What’s the problem with just looking at your foot strike pattern?

Well, for one thing, a foot-strike analysis mostly examines the force impacted on the body as a result of the heel strike. What we also have to consider is braking force — the amount of force transmitted upward into the body every time we move our feet forward as we run. (And in some cases, simply modifying your foot strike pattern may cause you to switch out one problem for another.)

Over-striding (putting your foot way out in front of your body) causes the foot to act as a brake every time it touches the ground. As a result of this gait, all of the extra energy from the foot’s “braking force” travels up the leg and affects the ankle, knee, and hip. 

A shorter stride, by comparison, has the foot landing closer to the body’s center of mass, resulting in less “braking force” than the longer stride. Although an aggressive rearfoot strike puts large impact forces through the body, it still causes less injuries than over-striding. 

If you are an “over-strider” the best way to  lessen your risk of injury  is by simply modifying your running cadence, or “stride rate” (the number of steps a runner takes per minute). The shorter the stride length and the quicker the stride rate, the faster and more efficient the runner. 

In addition to running faster and more efficiently, by increasing your cadence, you’re doing more than just moving your feet faster -- you’re changing the position of where your foot lands. Rather than having your foot land in front of your hips, it lands underneath you -- lessening impact forces.

Increasing your cadence 5-10% above the norm can significantly decrease your chances of injury. (6)

Music (playlists with music at 180 beats/min) or metronome apps are a simple yet effective tool for re-conditioning your running cadence. 

 

Professional Vs Recreational Runners

A recent study by Preece et al., (2019), sought to compare the biomechanical characteristics of high performance and recreational runners. Findings showed significant biomechanical differences between the two groups. 

High performance running was characterized by an increased vertical velocity of the center of mass, suggesting that their foot spent less time on the ground during what is known as the stance phase (initial contact and take off) of the gait cycle. 

In other words, pros spend less time on the ground and more time moving forward through the air. 

The high-performance running group recorded a flight time 11% longer than the recreational running group. 

The elite running group were also observed to strike the ground with their foot closer to their body.

This suggests that high-performance runners maintain their stride length with a prolonged aerial phase, rather than by landing with a more extended knee. 

There are characteristics in running mechanics that recreational runners can learn from elite runners, in particular as they relate to efficiency and consequent performance. Foot strike patterns during running can be modified and therefore have potential for prevention or treatment of running related injuries.

 

Foot strike patterns are like shoe sizes -- just because my shoes fit me well does not mean they’re the right fit for you. Understanding the biomechanical differences between foot strike patterns may be helpful in the search for a pattern that minimizes your specific biomechanical loads and maximizes your performance. 

The ground is lava -- improving your flight time by increasing your cadence and landing under your body not in front of it can dramatically reduce your risk of injury and get you to the finish line faster.

 

George Crouch, MSc

 

References

  1. Almeida, M. O., Davis, I. S., & Lopes, A. D. (2015). Biomechanical differences of foot-strike patterns during running: a systematic review with meta-analysis. Journal of Orthopaedic & Sports Physical Therapy, 45(10), 738-755.
  2. Anderson, T. (1996). Biomechanics and running economy. Sports Medicine, 22(2), 76-89.
  3. Ardigo’, L. P., Lafortuna, C., Minetti, A. E., Mognoni, P., & Saibene, F. (1995). Metabolic and mechanical aspects of foot landing type, forefoot and rearfoot strike, in human running. Acta Physiologica Scandinavica, 155(1), 17-22.
  4. Breine, B., Malcolm, P., Frederick, E. C., & De Clercq, D. (2014). Relationship between running speed and initial foot contact patterns. Medicine and Science in Sports and Exercise.
  5. Frederick, E. C. (1984). Physiological and ergonomics factors in running shoe design. Applied Ergonomics, 15(4), 281-287.
  6. Heiderscheit, B. C., Chumanov, E. S., Michalski, M. P., Wille, C. M., & Ryan, M. B. (2011). Effects of step rate manipulation on joint mechanics during running. Medicine and science in sports and exercise, 43(2), 296.
  7. Kulmala, J. P., Avela, J. A. N. N. E., Pasanen, K. A. T. I., & Parkkari, J. A. R. I. (2013). Forefoot strikers exhibit lower running-induced knee loading than rearfoot strikers. Medicine & Science in Sports & Exercise, 45(12), 2306-2313.
  8. Larson, P., Higgins, E., Kaminski, J., Decker, T., Preble, J., Lyons, D., ... & Normile, A. (2011). Foot strike patterns of recreational and sub-elite runners in a long-distance road race. Journal of Sports Sciences, 29(15), 1665-1673.
  9. Lieberman, D. E., Venkadesan, M., Werbel, W. A., Daoud, A. I., D’andrea, S., Davis, I. S., ... & Pitsiladis, Y. (2010). Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature, 463(7280), 531-535.
  10. Preece, S. J., Bramah, C., & Mason, D. (2019). The biomechanical characteristics of high-performance endurance running. European Journal of Sport Science, 19(6), 784-792.
  11. Roper, J. L., Harding, E. M., Doerfler, D., Dexter, J. G., Kravitz, L., Dufek, J. S., & Mermier, C. M. (2016). The effects of gait retraining in runners with patellofemoral pain: A randomized trial. Clinical Biomechanics, 35, 14-22.
  12. Running USA, 2020. Accessed 4/7/20. https://www.runningusa.org/
  13. Samaan, C. D., Rainbow, M. J., & Davis, I. S. (2014). Reduction in ground reaction force variables with instructed barefoot running. Journal of Sport and Health Science, 3(2), 143-151.
  14. Statista, 2020. Accessed 4/7/20 https://www.statista.com/statistics/190303/running-participants-in-the-us-since-2006/
  15. Van Gent, R. N., Siem, D., van Middelkoop, M., Van Os, A. G., Bierma-Zeinstra, S. M. A., & Koes, B. W. (2007). Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review. British Journal of Sports Medicine, 41(8), 469-480.
  16. Van Middelkoop, M., Kolkman, J., Van Ochten, J., Bierma‐Zeinstra, S. M. A., & Koes, B. (2008). Prevalence and incidence of lower extremity injuries in male marathon runners. Scandinavian Journal of Medicine & Science in Sports, 18(2), 140-144.
  17. Young, D. C. (2008). A brief history of the Olympic games. John Wiley & Sons.