Gretchen Reynolds on the science of fitness.
Many commentators have pointed out that the new movie “Jurassic World” is scientifically suspect, if not fantastical. But they have overlooked one of the more prominent ways in which the blockbuster diverges from established research. The movie’s heroine runs from rampaging beasts in high heels, without turning a hair or an ankle. But research on the biomechanics of wearing heels, including a new study of the effects on ankle strength and balance, says of her equipoise: “Ha.”
Obviously, what we wear on our feet affects how our bodies move. People who run barefoot, for instance, are more likely to land near the front of the foot with each stride than people wearing typical running shoes, who more commonly land on their heels.
But few other shoes affect the shape and functioning of the foot as dramatically as high heels do. According to a recent review of the available research about the footwear, walking in heels can “alter the natural position of the foot-ankle complex, and thereby produce a chain reaction of effects that travel up the lower limb at least as far as the spine.”
But while it’s clear that the feet and ankles of women who wear heels over a long period of time are different from those of women who usually wear flats, the progression of theses changes has not been well understood.
So for a new study published this month in The International Journal of Clinical Practice, researchers at Hanseo University in South Korea turned to a handy recruit group: young women at the university studying to become airline attendants who were required to wear high heels to class, since they would have to wear them if hired by a Korean airline. With each passing year, from incoming freshmen to seniors, the women would have one additional year of heel wearing behind them, making it easy to track physiological changes.
So the researchers invited 10 young women from each class to the lab and tested their balance with a wobbly board and the strength of their ankle muscles using computerized exercise machines.
The results were interesting. Compared with the freshmen, who were generally new to wearing heels, the sophomores and juniors displayed greater strength in some of the muscles around their ankles, particularly those on the inside and outside of the joint.
This difference between new and experienced heel wearers suggests that “wearing high heeled shoes may at first lead to adaptation and increased strength,” as the ankle responds to the stresses placed upon it by the unfamiliar shoes, says Jee Yong-Seok, a professor of exercise physiology at Hanseo University, who led the study.
But the senior women, who had been wearing heels the longest, showed weakening of those same muscles, compared even with the freshmen, as well as much weaker muscles along the front and back of the ankle and dramatically worse balance.
In fact, all of the upperclasswomen had worse balance than the freshmen, even as some of their muscles were strengthening.
What seems to have been happening, Dr. Yong-Seok says, is that the ratio of strength between the muscles on the sides of the ankles and those at the front and back became increasingly unbalanced over years of wearing heels, contributing to ankle instability and balance problems and eventually to a decline in the strength even of those muscles that had been stronger for awhile.
This finding is somewhat worrisome, says Neil Cronin, a biology professor at the University of Jyvaskyla in Finland who has studied heel wearing and wrote the recent review of related science.
Strength imbalances in the muscles around a joint, he says, particularly those around the ankle, “are known to increase injury risk in other muscle groups,” such as those in the hamstrings or upper leg.
Neither he nor Dr. Yong-Seok suggests that women eschew heels, however.
Dr. Yong-Seok does recommend that people who often wear heels strengthen their ankles whenever possible with simple heel lifts, for which you stand barefoot and then rise onto your toes repeatedly; and heel drops, during which you stand on the edge of a stair and slowly lower your heel over the edge.
Dr. Cronin also suggests slipping off heels while sitting at your desk, since wearing the shoes, even when not moving “can alter the resting length of the muscles and tendons around the ankle,” which could destabilize the joint and increase the risk of injury.
He also strongly advises against running in heels. The impact forces created “would be concentrated over a small region of the foot in high heels, creating regions of very high pressure,” he said, meaning foot pain. Plus balance and biomechanics are compromised, making running in heels “a very inefficient way to move.”
The lesson for fans of “Jurassic World” is: Don’t do what she did. “When attempting to run from a fast-moving, deadly animal,” Dr. Cronin said, “high heels are perhaps the worst choice of footwear possible. Running shoes would get my vote.”