Being a Doctor is Easy Its Like Riding a Bike Cup
The Checkup
As Easy as Riding a Bike
Your brain performs complicated engineering feats to allow you to balance on a bicycle. To thank it, wear your helmet, and make sure your kids wear theirs.
You probably remember the before and after of learning to ride a bicycle — and perhaps the joy of helping your children learn how. Riding together is a wonderful family activity — good exercise, outdoor time, and it even gets you places. But safety is a vital part of what parents should be teaching.
A recent study looked at bicycle-related injuries in children treated in emergency departments in the United States over a 10-year period from the beginning of 2006 through the end of 2017. Over that time, there were more than two million such injuries in children from 5 to 17, which the researchers calculated meant more than 600 a day, or 25 an hour.
"That's a lot," said Lara McKenzie, principal investigator in the Center for Injury Research and Policy at Nationwide Children's Hospital. Given the age of the most-injured group, 10 to 14, she said, "I feel this is a group where the parents might view the child as an experienced rider, but perhaps they're riding in places they shouldn't ride." The study did not include fatalities, since it was looking only at children in the emergency room and excluded the 12 who actually died there.
Of the injuries, 36 percent were to the upper extremities, 25 percent to the lower extremities, 15 percent to the face, and 15 percent to the head and neck. Many were related to falling off bikes, or crashing into something, Dr. McKenzie said, and when cars were involved, whether stationary or moving, the risk of traumatic brain injury (11 percent) and hospitalization (4 percent) increased.
Modeling good behavior is key, said Dr. Frederick P. Rivara, professor of pediatrics at the University of Washington; parents teach their children how to cross streets safely, he said, and they can teach them how to ride safely as well, riding with the direction of traffic, staying as far over to the right as possible, obeying traffic signals and stopping for red lights and stop signs.
Other safety rules bear repeating: "One bike, one rider," Dr. McKenzie said. Children under 10 should ride on the sidewalk, she said. Wear bright colors, wear reflectors. Children under a year old should not be passengers on any kind of bike, she said, even in a carrier or trailer, because their muscles are too weak to control their heads when the bike stops, and helmets, in this case, make their heads even heavier.
But as those children grow up and learn to ride, they are mastering a very complex process. Mont Hubbard and Ron Hess, each now a professor emeritus of mechanical and aerospace engineering at the University of California, Davis, worked on the project of modeling the system of bicycle and human rider from the point of view of mechanical engineering.
"Everyone knows how to ride a bicycle, but nobody knows how we ride a bicycle," Professor Hubbard said. "We think our way of imagining the human process is a way to understand that second half."
This is a system involving a human and a machine, and, he said, "the human is receiving sensory information and there is a control system in the brain creating the right corrective forces that need to be applied to the handlebar to get the bicycle to stand up."
But processing that information isn't simple, by any means. Dr. Hess said it turned out to be more complicated than modeling pilots and airplanes.
To make adjustments and keep the bike upright and moving forward, the human brain has to receive sensory information about the position and motion of the body in space and the pressure applied to the handlebars, visual information, and vestibular information about balance and the roll rate of the bike. "All three of those have to be used successfully to ride a bike," Dr. Hess said, with information coming in from different kinds of sensory receptors, in the eye, in the muscles, in the inner ear.
"If the rider doesn't do the right thing, if his or her actions aren't adequate to stabilize the bicycle, then the bicycle will fall over," Dr. Hubbard said. In engineering, he said, this is called a control law: "The control law says, if I'm falling to the right, what do I do, I turn the wheels to the right," in a constant process of subtle adjustment and balance to keep the bicycle upright and moving forward. The rider may not understand the differential equations in the model, he said, but the brain is making these calculations.
In their model, "the human takes those streams of information and creates from those various streams a control signal which is a force to push the handle bars," Dr. Hubbard said. They were able to build a bicycle that could right itself, using these equations to make adjustments, taking into account the important variables like the tilt angle of the bicycle. The model predicted, for example, that before making a turn to one side, there would first be a smaller steering turn to the other side, and Dr. Hess said he had found it satisfying to see that borne out by observing skilled riders.
Riding a bicycle, however complex, is often used as shorthand for something which, once learned, is never forgotten. Dr. Hubbard compared it to a young child learning to stand up, working out the muscle control involved in balance, pushing with the toes and adjusting to avoid falling over.
Larry Squire, who is distinguished professor of psychiatry, neurosciences and psychology at the University of California, San Diego, described this kind of learning as "habit learning or skill learning," which is neurologically distinct from what is called "declarative learning," that is, learning facts and events.
Learning and remembering facts and events is centered in the hippocampus and adjacent structures in the medial temporal lobe of the brain, but habit learning and motor skills like riding a bicycle involve a different part of the brain, the basal ganglia. This kind of learning is a more unconscious process, Dr. Squire said, in that you cannot necessarily describe what you know, but it creates a kind of memory that does indeed last for a long time.
So back to safety: Get out there and ride those bicycles, but ride them safely, on safe paths, with the proper equipment. Ride with your kids, and make memories. "We do want kids to ride, families to ride, we do want them to wear helmets, every time, parents too, even if they didn't when growing up," Dr. McKenzie said.
Ride with your children, and teach them by example, not only how to ride but how to ride safely. Above all, protect those brains, which can do such amazing things.
Source: https://www.nytimes.com/2018/07/23/well/as-easy-as-riding-a-bike.html