While connected objects are popular with jogging enthusiasts, an American researcher has discovered that the latter, who can notably avoid stress fractures, do not measure the right thing.
It starts with persistent pain in the foot or lower leg. Then, this pain becomes more and more intense, even accompanied by swelling. This is one of the most common injuries among runners: the stress fracture.
These small cracks in the bone can prevent a runner from practicing their sporting activity for months. Nowadays, there are connected objects, sensors supposed to avoid the stress fracture. This portable technology, called “wearable” in English, represents a market of several billion dollars. The problem, according to an American researcher, is that it does not measure the right factors. Its findings are published in the journal PLOS One.
The contraction of muscles during running weakens the bones
Indeed Karl Zelik, of Vanderbilt University (Tennessee, United States), discovered that the sensors linked to this technology only measure the impact of the foot on the road, and not the force exerted on the bones. By working with a local running club, an orthopedic specialist and engineers from his university, he also found that in reality it is the contraction of the muscles that forces the bones, and not the impact of the foot on floor.
A finding still ignored today by the clothing and connected objects industry. “We reviewed recent scientific literature and found that more than 50 publications reported or interpreted their results each year, based on the incorrect assumption that impact on the ground was representative of stress on bones and muscles. inside the body,” says Karl Zelik.
Soon a new technological tool?
Karl Zelik’s team analyzed 10 runners on a special treadmill, equipped with sensors, in order to record the impact of the foot on the ground. The researchers also used high-speed motion capture cameras. “We then combined these signals using biomechanical algorithms to estimate the compressive force felt by the tibia, a common location for stress fractures”, details Emily Matijevich, researcher who participated in the study.
First observation: the pressure of the foot on the ground is not necessarily correlated to that exerted on the tibia. Sometimes it was even lower! Karl Zelik’s team recently filed a patent application for a system with several wearable sensors, which merges these two elements. In order to give a better idea of bone stress, and to prevent injuries.
.
