- HMS Community Values
- Introduction to Clinical Research Training
- Letter from the Chairman
- Medical Education
- Application Form and Instructions
- United Kingdom Clinical Scholars Research Training
- Award Listing
- Vanderbilt Hall
- Award Summaries
- Financial Aid
- Spring Preview
- Frequently Asked Questions
- Office of the Registrar
- Award Recipients
- Campus Planning and Facilities
- Ombuds Office
- Research Administration Contacts
- Committee on Microbiological Safety
- Contact Us
- Human Resources
- The Academy
- Office for Academic and Clinical Affairs
- Joint Committee on the Status of Women
- Global Health Research Core
- Administration Who's Who
- Cafeteria Menus
- Community Announcements
- HR Stories
- Faces of HMS
- Safety Tips
- Longwood Shuttles & MBTA
- Spotlight Stories
- Inaugural Pride on the Quad Day
- Spring Cleaning: Earth Week 2015
- Celebrating the Past, Preparing for the Future
- Spotlight on External Education
- A Work in Progress
- HMS to Oversee Undiagnosed Diseases Network
- New Recycling and Reuse Resource
- Growing Green: Sustainability Committee Covers Harvard Longwood Campus
- Study by HMS student evaluates FDA approval of cardiac devices
- Play Me, I'm Yours!
- Exploring the Nervous System
- HMS Brings Comfort and Convenience to New Mothers
- RIA Program
- Spotlight on Angela DePace
- Spotlight on Admissions
- Spotlight on Rick Born
- Spotlight on the New Year
- Backing Up Science on the Quad
- Combating a Crisis
- Improved policies, improved care
- Strengthening Collaborations
- Contact Us
- Global Clinical Scholars Research Training Program
- HMA Standing Committee on Animals
- Office of Research Compliance
- Harvard Medical School Event Calendar
- Office of Diversity RIA Program
- The Dean's Perspective
- Department of Pathology
- Harvard Mahoney Neuroscience Institute
- OHRA Home
- Office of Research Subject Protection
- Alumni Association
- Cancer Biology & Therapeutics Program
- Celiac Program
- Department of Medicine
- HMS Information Technology
- HMS TransMed Program
- Introduction to the Practice of American Medicine
- Office of Communications & External Relations
- Big Data In Healthcare
- Institutional Planning and Policy
- Master of Medical Sciences In Clinical Investigation
- Office of Global Education
- Portugal Clinical Scholars Research Training Program
- Safety Quality Informatics and Leadership
- South American Clinical Research Training Program | SACRT
- Southeast Asia Leadership Program
- Shenzhen-HMS Initiative in International Education
- Contact @HMS
- Office of Global Education
- Human Resources
- Jobs @ HMS
- Dental Medicine
- Harvard University
- Contact us
Where Runners Go Wrong
As evidence has mounted that distance running is not just a natural human activity enjoyed by millions, but one that played a key role in evolution, a puzzle has emerged.
Why, if humans are so well adapted to running long distances, do runners get hurt so often?
A study out of Harvard Medical School and the National Running Center at Harvard-affiliated Spaulding Rehabilitation Hospital provides a puzzle piece, linking injury to the pounding runners’ bones take with each step. The work, led by professor of physical medicine and rehabilitation Irene Davis, found that a group of runners who had never been hurt landed each footfall more softly than a group who had been injured badly enough to seek medical attention.
Statistics on such injuries vary, but somewhere between 30 percent and 75 percent of runners are hurt annually, a number that has led researchers to investigate a wide array of possible explanations, from modern running shoes to stretching, running frequency, weight, biomechanical misalignment and muscle imbalance.
A 2012 Harvard study, for example, zeroed in on injury rates among track and cross-country athletes who land on the forefoot versus the heel. Researchers led by Daniel Lieberman, the Edwin M. Lerner II Professor of Biological Sciences and chair of the Harvard Department of Human Evolutionary Biology, were probing the idea that before the advent of cushioned running shoes, most runners landed on the ball of the foot because landing on the heel would be too painful. Landing on the forefoot allows the foot and ankle to absorb some of the landing shock, an impact that today’s running shoes can’t completely erase for those who land on their heels.
With most runners being heel-strikers today, the added shock, multiplied over thousands of footsteps, could explain high injury rates. The 2012 study added fuel to the debate, finding a two-to-one difference in repetitive stress injuries between heel- and forefoot-strikers.
Davis’ research focused on heel-strikers exclusively, since they make up most of today’s runners, and examined a cohort seldom studied, partly because they’re pretty rare: those who have never been injured.
“We can learn a lot from that group,” Davis said. “What are they doing right?”
Davis and colleagues recruited 249 female recreational athletes who each ran at least 20 miles a week. They investigated the participants’ strides by having them run over a force plate that recorded the impact of each step.
The runners agreed to respond to a monthly online questionnaire that detailed injuries over two years. With the results in, researchers first examined reports from the 144 who experienced a mild injury and the 105 who didn’t, finding little difference between the two large groups.
Then they examined the smaller groups at the two extremes of the spectrum: those who had been injured seriously enough to seek medical attention and those who not only went uninjured during the course of the study, but who reported never having been injured.
Significant differences emerged between the two groups in a variable called “vertical average loading rate,” which was highest in the seriously injured runners and lowest in the uninjured group.
Vertical average loading rate, however, doesn’t measure the absolute peak force the body feels, which did not seem to make a difference. What did, Davis said, was suddenness of impact, where softer landers were better off. Davis said it is akin to the difference between jumping from a height and landing stiff-legged versus allowing ankles, knees and hips to flex.
The key action happens over a vanishingly small amount of time, Davis said. During a typical running stride, the foot is in contact with the ground for just about a quarter of a second; the fraction that made the difference between the two groups was only 50 milliseconds. Even so, when repeated thousands of times, that small difference can take a toll, Davis said.
The difference can be visible. One never injured multi-marathoner’s stride was so smooth, Davis said, “She ran like an insect over water.” Weight was not a factor, with heavy runners among the light-footed and lighter runners among the stompers.
The takeaway is that a softer footfall appears to reduce the likelihood of injury. Previous studies show that one potential approach for runners trying to cut the chances of injury is to adopt an impact-absorbing forefoot strike — which Davis herself, a barefoot runner, uses. But even the committed heel-striker can learn from the gliders, Davis said.
For one, their soft-landing steps tend to be very quiet. Runners should take out the earbuds and pay attention to the sound of their footsteps.
“If you land louder, it’s harder,” Davis said. “It’s work, but you can make your foot-strikes softer.”
Adapted from a news story from the Harvard Gazette.
Stay informed via email on the latest news, research, and
media from Harvard Medical School.