Friday , October 7 2022

Engineer, advisor to the NFL Players Association finds problems with current sensors – ScienceDaily


It begins as persistent and irritating pain in the foot or lower leg, becomes more intense, perhaps with swelling, and soon a runner knows that it is being marginalized by one of the most common injuries: a fracture of stress . These small crevasses can stop the training for months or even finish a sports season.

A segment of the multi-billion dollar portable industry aims to save the potential victims of this destination, but an engineering professor at the University of Vanderbilt found a major problem: the devices measure the damage.

Working with a local racing club, an orthopedic specialist who advises the NFL Players Association and a team of Vanderbilt engineers, the assistant professor of Mechanical Engineering, Karl Zelik, discovered that the sensors only measure the impact of standing pavement that makes practically everyone do it, explain to the users little about the strengths of the bones that lead to stress fractures.

His research confirmed that the vast majority of the force on the limbs is actually the contraction of the muscles, not the impact of the foot on the floor, a finding largely ignored by the industry of the " Portable device as well as for many scientific studies.

The research by Zelik, which appears today in the magazine reviewed by experts PLOS One and entitled "Measures of the ground reaction force are not strongly correlated with tibial bone loading when you are experiencing speeds and pending: Implications for science, sport and the technology that you can use", offers the A clearer and simpler demonstration of the problems underlying the existing tools and the predominant methods to evaluate bone stress and the risk of injury.

"We looked through the recent scientific literature and found that more than 50 annual scientific publications report or interpret the results from this supposed matter that the ground reaction force is representative of the internal load of L & Structure: the stress of the bones and muscles in the inner body, "said Zelik, an old university song and featured in the field. "The measure of the ground reaction force may be convenient, but it is the wrong signal."

The accelerometer and the pressure sensors that can be used on the market can help control the risks of bone stress injuries, but only if they combine information about the strength of the soil's reaction and the strength of muscles that are & # Take advantage of the ones. In general, it is not possible to assume that the increases in the soil reaction force indicate increases in bone stress, said Emily Matijevich, Ph.D. mechanical engineer. Zelik's laboratory student and herself an avid runner.

Matijevich performed the laboratory work that the study describes, testing 10 runners in a range of speeds and slopes.

"We use high speed cameras to capture movements to track the movement of corridors and a special tape of force measurement to record the ground reaction force under their feet," he said. "Next, these signals were combined using biomechanical algorithms to estimate the compression force experienced by the tibia in the stem, a common place for stress fractures. In almost all cases , we found that the soil reaction forces were not strongly correlated with tibial bone loading. "

In several cases, lower ground reaction forces actually meant a greater tension in the tibia, a finding that most athletes believe and counteract the way the most existing portable ones work.

This investigation began two years ago, when the assistant professor at the University of Vanderbilt, Leon Scott, who works in the health and safety committees of the NFL Players Association, asked Zelik a question Simple: Usable sensors could be used effectively to prevent the stress fractures that Scott saw at his clinic every day?

Matijevich, Zelik and Scott now explore new ways to monitor bone stress in a non-invasive way and have recently submitted a patent application for a system that merges data from various usable sensors to estimate the load of the tibia so much of the muscular contractions as of the forces of reaction of the ground. Look for business partners to develop this new usable technology and explore applications for recreational runners, military cadets and elite athletes.

Scott said that the combination of usable sensors and the new algorithms that the computer is developing gives a much better image of bone stress, with the potential to help runners reduce the chance of injuries .

"There's only a lot you can do when the game goes because they are high speed injuries, but we can do something about stress fractures during training and conditioning," Scott said. "Right now, we do not have excellent tools to tell us what's going on with bones other than experience and anecdote, and unfortunately I do not know enough."

Source of the story:

Materials provided by Vanderbilt University. Original written by Heidi Hall. Note: Content can be edited for style and duration.

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