UK researchers have developed smart insoles that accurately measure the forces created when a foot hits the ground in the real world. The cutting-edge technology can help athletes perform at their best and avoid injuries, as well as aid in the rehabilitation of injured patients.
Your foot pushes against the ground when you run, jump, or walk, and the ground pushes back in the opposite direction with an equal amount of power. These are GRFs. They are important because they affect how our bodies respond and move when we exercise, reports Paul McClure in New Atlas.
In order to create smart insoles that measure GRFs in three dimensions more naturally and correctly, scientists from the University of Portsmouth in the United Kingdom partnered with the tech company TG0. For sports science, rehabilitation, and injury prevention, these insoles offer practical movement analysis.
“We wanted to create an affordable and portable alternative to expensive lab equipment,” said the study’s lead author, Dinghuang Zhang, PhD, a former postgraduate researcher from the University’s School of Computing and current associate in the knowledge transfer program (KTP) at TG0. “These insoles could help athletes improve performance, assist doctors in rehabilitation, and even help people track their movement for general health.”
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The ability of the novel insoles to assess the medial-lateral (Fx), anterior-posterior (Fy), and vertical (Fz) components of GRF gives them their three-dimensionality. The side-to-side force is simply referred to as medial-lateral. When you take a step to one side or the other, such as when you make a rapid lateral movement in basketball, it measures the push or pull that happens. The forward-backward force, which gauges the acceleration or braking that takes place when running, is anterior-posterior. The up-and-down force that the ground exerts on your foot as it lands is known as vertical force. It can be viewed as the force that sustains the weight of your body and is typically the strongest of the three. Understanding healthy gait and how it is impacted by injury, muscle fatigue, posture and balance, and neuromuscular diseases requires knowledge of all three.
To monitor foot pressure and movement, the team’s TG0 Smart Insole has an inertial measuring unit (IMU) and integrated pressure sensors. An IMU is a device that has a number of sensors that measure motion by determining the foot's rotation (gyroscope), speed in various directions (accelerometer), and direction of travel (magnetometer). To forecast GRFs, machine learning is fed all of the data collected by the IMU and pressure sensors.
The TG0 Smart Insole was tested by the researchers on five healthy adults of varying heights and body weights. To reduce data variability brought on by muscular stiffness or equipment unfamiliarity, participants initially engaged in a walking and jumping warm-up. After the insole was fitted, patients were instructed to execute a set of exercises on a force plate, including deep squatting, walking and jogging in place, swaying to the left and right, jumping in place, and jumping forward and backward.
The researchers discovered that the insole accurately predicted GRF with an error rate of 4.16% after comparing the GRF data from the insole with the force plate, which served as a reference. The normalized root mean squared error (NRMSE), a metric for predicting accuracy in comparison to gold standard force plate readings, is reflected in the error rate. Although there is a low mistake rate, it is crucial to take into account the environment in which these insoles will be utilized because the allowable error margin may differ based on the application, such as healthcare and rehabilitation versus sporting performance. NRMSE errors of 8% to 20% have been observed in investigations on alternative GRF measurement techniques, such as motion sensors or pressure insoles, the researchers pointed out.
The smart insoles use Bluetooth low-energy (BLE) to connect to a USB dongle that is connected to a PC. They include a built-in battery that can gather data constantly for about eight hours.
The researchers anticipate a variety of uses for their smart insoles. They could lower the risk of injury, improve training, and assist athletes in tracking their movements. They might be used by physicians and physical therapists to keep an eye on patients who are recovering from injuries or have movement problems. Additionally, they could gather information to further the study of biomechanics and sports science.
The study was published in the journal Intelligent Sports and Health.
