On a regular basis, health and fitness journalist Gretchen Reynolds, who contributes to the Well Blog of the New York Times, has done a stellar job writing about the information, studies, and reports emerging rom the frontlines of exercise research. The topics are timely, and she is able to expertly highlight the salient facts. Best of all, when it comes time for readers to submit their comments to the blog, the debate becomes even more lively, more informed, and usually “civil” unless it centers on barefoot running. This past week, the Well’s topic of discussion focused on “footstrike and injury” and was based on a study recently published in the Journal of Medical Science and Sports Exercise. The co-authors of the study, led by Daniel Lieberman of Harvard’s Department of Evolutionary Biology, summarized their findings as follows:
“This retrospective study tests if runners who habitually forefoot strike have different rates of injury than runners who habitually rearfoot strike.
We measured the strike characteristics of middle and long distance runners from a collegiate cross country team and quantified their history of injury, including the incidence and rate of specific injuries, the severity of each injury, and the rate of mild, moderate and severe injuries per mile run.
Of the 52 runners studied, 36 (59%) primarily used a rearfoot strike and 16 (31%) primarily used a forefoot strike. Approximately 74% of runners experienced a moderate or severe injury each year, but those who habitually rearfoot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike. Traumatic injury rates were not significantly different between the two groups. A generalized linear model showed that strike type, sex, race distance, and average miles per week each correlate significantly (p<0.01) with repetitive injury rates.
Competitive cross country runners on a college team incur high injury rates, but runners who habitually rearfoot strike have significantly higher rates of repetitive stress injury than those who mostly forefoot strike. This study does not test the causal bases for this general difference. One hypothesis, which requires further research, is that the absence of a marked impact peak in the ground reaction force during a forefoot strike compared to a rearfoot strike may contribute to lower rates of injuries in habitual forefoot strikers.”
As Ms. Reynolds observed, “This finding, the first to associate heel striking with injury, is likely to fuel the continuing and not-always civil debate about whether barefoot running is better. (It hurts to hit the ground with your heel if you’re not wearing shoes.) But both Dr. Lieberman and Mr. Daoud, now a medical student at Stanford University, are quick to point out that their study did not in any way address the merits of going barefoot.
All of the Harvard runners wore shoes, and most, as Dr. Lieberman says, ‘wore different shoes every day of the week.’ Some ran in well-cushioned shoes and became injured, while others did not. Likewise for those who usually ran in minimal racing flats. Some got hurt; some did not. And forefoot striking, over all, was not a panacea. Many of the forefoot strikers were felled by injuries.But in general, those runners who landed on their heels were considerably more likely to get hurt, often multiple times during a year.”
Nearly 200 readers offered their own take following the article, including several with ties to the Natural Running Center — Executive Director Dr. Mark Cucuzella, and Health and Fitness Advisors Danny Dreyer and Dr. Steve Gangemi (aka “Sock Doc”). Their comments appear below. — Bill Katovsky
As always a great read provoking passionate comments. Bill Bowerman observed in his 1967 book “Jogging” that 70% of the time the runner “lands first on the heel of the foot, rocks forward and takes off from the ball of the foot”. He later comments on shoes: “In general shoes should be sturdy, with rubber, crepe, ripple, or neolite sole. Probably the shoes you wear for gardening or around the house will do just fine.” There are many beautiful pictures of “joggers” defined as a “mix of walking and running”. “Jogging” was and is for fitness and health. All are in thin shoes, some land on the heels, but they are not overstriding. The year of 1967 was before the padded, elevated heel shoe which changed heel landing from the smooth roll off the heel to a harsh impact in most. No one in any of these classic pictures is landing with the outstretched leg. Gretchen your column two weeks ago talked about the “default pattern” that the footwear sets up.
So what does this mean? It is not about what hits first but more how you land in relation to your center of mass and whether you are elastic in your stride. I run barefoot on roads and when going mellow I too gently roll off the heel to the ball and load the spring of the Plantar Fascia/Achilles for recoil. When running faster barefoot my forefoot tends to land before the heel settles. I am not overstriding, so it is not just about the foot. Dr. Lieberman is right is his scientific acumen. If the heel lander is well they are doing something right until proven otherwise. A full gait analysis with forces might shed light if some adjustments for long term safety might be considered. The Harvard Trial is an observational trial and makes us think.
Dr. Mark Cucuzzella
Thank you, Gretchen, for bringing this to light in your article. A few things need to be brought up when asking about whether or not someone’s running form leaves them more susceptible to injury than someone else’s. When studying injury rates in runners it is important that all the phases of a runners gait be studied when looking for cause of injury. There has been so much debate on foot strike lately that we’re led to believe it’s all in the foot strike. But, there are four phases in a runner’s stride: strike phase, support phase, toe-off phase and flight phase… the first three of which can all be sources of injury.
In my experience, from my experience with coaching thousands of everyday runners, I believe that more injuries happen during the toe-off phase than during the landing phase. Very little attention is paid to this and it has remained under the radar of most running “experts” because everybody assumes that the only way to run is to push yourself forward with your legs. The intense forces put onto the metatarsals, achilles tendons and calves during the propulsion phase can be equal to a multiple of the weight of the runner. All of those small muscles, ligaments and tendons are not designed to carry the bulk of the weight of a person. That’s precisely why ChiRunning focuses on lifting the ankle and gently peeling the foot off the ground so as to NOT put any undue stress on the metatarsals or lower leg muscles during the lift-off stage.
Runners get injured for a variety of reasons, some which Gretchen briefly mentioned such as a poor diet and too much training. But ultimately it all comes down to the biomechanics of the runner, or any athlete for that matter, as the biomechanics are significantly influenced by those very factors – diet, training, and what you wear, (or don’t wear) on your feet.
Muscle imbalances occur when your body is under too much stress. If you’re training too hard or too frequently with inadequate rest, if you’re under too much stress at work or home, if your diet is loaded with refined foods (sugars and oils), or if you’re wearing shoes that alter mechanics, then muscle imbalances result and pain and injury follow.
So minimalist-type shoe and barefoot runners will still get injured if they train improperly and live their lives under too much stress, but often they are taking just one more injury-provoking factor out of that injury-prone equation – that of poor footwear.