I got a call last week inviting me back to the Skeletal Biology lab as a test subject for their newest research project. The photo at the right shows me on the tread mill, after one of the data gathering sessions, with reflective, silver motion capture balls taped to my leg. Dan Lieberman and his lab are asking interesting questions and learning fundamental things about the mechanics of human motion. Strange as it may seem, no one before has looked in detail at what happens when your feet strike the ground.
If you haven’t seen it yet, do check out their web site, Running Barefoot, where the folks at the Leiberman lab discuss the “biomechanics of foot strikes
and applications to running barefoot or in minimal footwear”. As the subtitle makes clear, the title is a bit of a misnomer. The research and web site address foot strikes and how heel striking differs from forefoot striking, regardless of whether you’re wearing shoes. Shoes are useful tools, as anyone who runs in Boston winters can attest.
We talked about my impressions from participating in the previous study and it dawned on me that perhaps I wasn’t heel striking after all. While the heel of the shoe was contacting the ground before the front of my foot, my foot could well have been flexed downward, positioned to strike on the forefoot. The mechanics of this would be similar to that shown in the bottom pictures on this page (note how the bones align in the ankle and foot on the elite Kenyan runner) or in this video.
How about 40 mph? A newly published study from the Journal of Applied Physiology suggests that the theoretical limit to human speed might run that high.
“Where once the maximum top speed of a human being was thought to be around 28 mph, a new study suggests that a trained runner could achieve speeds of 40 mph, or perhaps even more.”
“The prevailing view that speed is limited by the force with which the limbs can strike the running surface is an eminently reasonable one,” said Weyand, associate professor of applied physiology and biomechanics at SMU in Dallas.
“If one considers that elite sprinters can apply peak forces of 800 to 1,000 pounds with a single limb during each sprinting step, it’s easy to believe that runners are probably operating at or near the force limits of their muscles and limbs,” he said. “However, our new data clearly show that this is not the case. Despite how large the running forces can be, we found that the limbs are capable of applying much greater ground forces than those present during top-speed forward running.”
In contrast to a force limit, what the researchers found was that the critical biological limit is imposed by time -– specifically, the very brief periods of time available to apply force to the ground while sprinting. In elite sprinters, foot-ground contact times are less than one-tenth of one second, and peak ground forces occur within less than one-twentieth of one second of the first instant of foot-ground contact.
This clip shows San tribesmen in the Kalahari Desert killing a kudu using persistence hunting. Over the course of eight hours, through the hottest parts of the day, the San hunters forced the kudu to run until it collapsed from heat exhaustion.
See prior Bounce articles about persistence hunting and the endurance running capabilities of humans:
What businesses are booming in the current economic climate? The answer is either energy-efficient replacement windows or the running industry.
The talk among vendors at the Boston Marathon expo last month was how surprisingly strong business was for them.
Writing in the Wall Street Journal, Cameron Stracher suggests the reasons why and makes a connection between the current running boom and the previous one:
Running is an inexpensive activity that requires little in the way of equipment — a decent pair of shoes, shorts, socks and a T-shirt and you’re ready. The playing field is any free land, sidewalk, park or road. (It’s not surprising that America’s first running craze was born of the economic malaise of the 1970s.)
Do running shoes cause running injuries? That’s the question posed by Popular Mechanics in this look at technology in the running shoe industry and recent advances in the study of human motion.
One study of 753 runners (videotaped in two races) showed that 80% of runners ran with a heel strike motion and the balance with a mid-foot strike. Interestingly, for the faster runners (those running faster than a 5:18 pace per mile) only 45% had a heel strike, while the majority (55%) of the fast runners used a mid-foot strike.
That’s a suggestive piece of data.
PM looks at how modern technology is being used to analyze running gaits, how modern running shoes are designed and how some labs are trying to create shoes that mimic the barefoot running motion.
For more reading on barefoot running and the evolution of running capability in humans:
Tarahumara runner Arnulfo Quimare runs alongside ultra-runner Scott Jurek in Mexico's Copper Canyons
When early humans began running on the plains of Africa thousands of years ago they didn’t have shoes. In an article taken from his new book Born to Run, Christopher McDougall takes a skeptical look at the purported benefits of highly cushioned running shoes.
Christopher compares the foot health of people in high-tech running shoes with those of the Tarahumara indians of Mexico who “run with only strips of old tyre or leather thongs strapped to the bottom of their feet”. The conclusion is surprising to many (especially to shoe manufacturers). Barefoot running strengthened feet and led to fewer injuries.
Still skeptical? One of the anecdotes Christopher relates is how Nike research on barefoot runners at Stanford led to the invention of the Nike Free, a shoe whose marketing tag line is ‘Run Barefoot’.
Can’t say that this is a question I’ve thought much about. But a recent study by Daniel E. Lieberman suggests that the relatively shorter toes of humans, compared to other primates, provided a mechanical advantage that enabled early humans to run more efficiently in hunting game.
Last fall, The Bounce looked at evidence for endurance running as an early human hunting strategy. Several studies over recent years have pursued the idea that early man began his hunting career by running down game. Not by outracing animals in a sprint, but by tiring them out over a long distance endurance run and forcing them to fall from overheating and exhaustion.
A recent article describes the Lieberman study in the context of a fascinating new book, Born to Run, which describes “the reclusive Tarahumara Indians of Mexico’s deadly Copper Canyons … For centuries they have practiced techniques that allow them to run hundreds of miles without rest and chase down anything from a deer to an Olympic marathoner while enjoying every mile of it”.
Richard Donovan runs 7 marathons on 7 continents in 5 days
… seven marathons on seven continents in five days. Irishman Richard Donovan of Galway started on January 31st with a marathon in Antarctica, then flew to Cape Town-South Africa, Dubai, London, Toronto, Santiago-Chile and finally Sydney. Running a marathon in each of the seven continents of his seven stops and finishing after only 129 hours.
Happened to catch the women’s mile at the Millrose Games live Friday night on ESPN. Kara Goucher owned the race, finishing by over four seconds ahead of the pack. She’s currently preparing for the Boston Marathon and ran the mile in New York this week as a break from marathon training. As she notes in this interview, it was a chance to unleash her aggression in the midst of grueling distance training and “man up” a bit.
I’ve been to Point Reyes a couple of times for day hikes (which on more than one occasion finished with a pint of Guinness at the Pelican Inn). But this 22 mile adventure run loop looks like a wonderful way to spend a day by the ocean. And who knows, a pint at the end of the road might be just the right motivation around mile 18.