A reader brought to my attention the growing trend of barefoot running, given fuel recently by this study:
Foot strike patterns and collision forces in habitually barefoot versus shod runners.
Department of Human Evolutionary Biology, 11 Divinity Avenue, Harvard University, Cambridge, Massachusetts 02138, USA. firstname.lastname@example.org
Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
It's an interesting idea, and certainly has its appeal, falling in line with other fitness trends such as functional strength training and the naked warrior concept. I've known people who have been running barefoot since the mid-90s.
But I suspect the faddishness of the trend, and I see some real problems with the research. The first is that it was not until last fall, with the Wolf study, that a decent examination of the consistency of lower extremity kinematics was even performed (to my knowledge, at least). Without that base consistency data, drawing conclusions from a comparison of shod versus barefoot kinematics is perilous. How do we know that the data from the Lieberman study (and others) even falls outside the range of normal variation? The fact is, we do not. So to to make conclusions about technique from such studies is rash.
While the research does show some force reduction at the joints, from that data the researchers are *presuming* a reduction of injury. There are not any studies which actually show a reduction of injury, and it is quite possible that none will be found. Lieberman admits this limitation in his study. What is most probable is that barefoot running may tend to reduce the risk of certain types of injuries, while increasing the risk of others, and as I note below, the benefits are likely to vary widely based on individual biomechanics. There truly is no such thing as a free lunch.
Similarly, performance has not been evaluated. The argument held forth thus far is the "Ethiopian runners do it and they are the best," which is an argument beset with obvious problems, from cardiopulmonary functioning to femorotibial ratios. Until I see some good studies, I am inclined to dismiss barefoot running performance claims.
Interestingly, the kinematics of shoeless running point to the fact that, in all likelihood, the runners who do benefit most from shoeless running are those that are free of foot dysfunction in the first place. Which makes sense.
It is important to note that the foot scans I'm providing are not with the intent to provide a rationale to fit every athlete with orthotics, but more to detect those individuals whose foot dysfunction or pathology tends to increase their risk of injury or hinder their performance. For such individuals, there is absolutely no data to suggest that they would benefit from barefoot running and a wealth of research to suggest that custom orthotics would be beneficial.
I'm not a one-size-fits all kind of doctor, and I may happily recommend seemingly contradictory advice to two different patients with the same (apparent) problem, because I think that any protocol needs to account for the huge individual variability in physiology and biomechanics. It is one of the core ingredients missing in most of mainstream medicine.
So I'm not going to utterly dismiss barefoot running out of hand, because it may have some genuine utility for some people. But the majority of runners, I suspect, will continue to benefit from a well-made shoe and proper foot support.