Protective footwear should keep feet and toes safe against impacts and crushing injuries, corrosive chemicals and punctures from sharp objects. Workers need to be able to trust that they don’t risk injury if they step on a nail.
But individuals who stand or kneel through long workdays should also be able to avoid aching hips and knees due to stiff and rigid footwear. Until now, the challenge has been to find the balance between safety and comfort.
Tore Christian B. Storholmen is a senior research scientist and has led the Lightfoot project. Photo: SINTEF
Researchers have turned the way shoes are produced upside down with a revolutionary new safety shoe concept. Users can select footwear according to their weight class, the flexibility they want and the tasks they have to perform.
“Many people who have jobs where they walk a lot on hard surfaces develop musculoskeletal disorders. Shoes are an important contributor to this problem. Our goal is to create a shoe that provides better foot health,” says Tore Christian Storholmen.
Storholmen is an industrial designer and senior research scientist at SINTEF. In recent years, he has worked closely with manufacturers, end-users and industry partners in the search for better footwear for workers on the floor. Now they are reaping encouraging results from the project, which they have named Lightfoot.
Unique solution for nail protection
The result is a protective shoe with a softer sole, which minimizes strain on the heel and provides better space for the toes when kneeling.
“The classic way to make shoes has been to inject foam into a mould that connects the outsole to the finished upper of the shoe,” says Storholmen.
The material that is injected forms the part of the shoe that you step on, and is called the midsole.
One of the goals of the project has been to reduce the climate footprint in the manufacture of protective footwear. The researchers have managed to achieve a 52 percent reduction, thanks largely to the fact that they have moved away from using leather in the upper. PHOTO: SINTEF
“The problem has been that the nail protection needs to be inserted on top of this midsole and usually consists of a thick, strong textile material. It rests on top of the foam that you’ve injected, ruining the comfort,” says Storholmen.
“Our trial users have reported improved comfort. One user said that for the first time in over ten years he was able to stop taking painkillers due to the pain in his knees and joints.
So the Lightfoot researchers tried placing a traditional insole on top of the nail protection.
“But it’s pretty thin,” Storholmen says. “So we realized that if we were going to be able to do something about the shock absorption and ergonomics, we had to change the entire production method.”
Better shock absorption
The researchers instead chose to place the nail protection in the bottom of the shoe. They removed the foam layer, left the shoe an empty shell and instead introduced replaceable midsoles with different degrees of firmness.
The replaceable midsoles “are much thicker than traditional insoles, as much as three centimetres at the heel. This way we move the soft materials closer to the foot, and people can choose the sole based on their own weight class and needs,” says Storholmen.
Changing the production method itself has allowed the researchers to reduce the forces acting on the heel, while simultaneously improving stability. Here we see test participant Johannes Kaspersen Johannessen and test manager Maria Suong Tjønnås from SINTEF. Photo: SINTEF
Tests analysed 20 000 measurements and showed that the new shoe type provides better shock absorption during natural walking when compared with a representative selection of established safety footwear models on the market today, including the supplier’s own reference model.
“We achieved a significant reduction in heel forces and significantly better foot stability. The forces acting on the heel have been reduced by over six percent,” says Storholmen.
“We worked closely with the manufacturer in Italy, who has had to completely rethink the production method. They have been producing safety footwear for forty years and say they have never seen anyone tinker with so many elements at once.
Six percent might not sound like much, but for a person weighing 80 kilos, it corresponds to five kilos less load for every single step they take. Over the course of a work day, this can amount to several tonnes less total load on the body.
Twenty thousand steps a day
The researchers have also had personnel working in offshore and land-based industries try out the shoes over several months. The feedback confirms the laboratory study, Storholmen says.
“Our trial users have reported improved comfort. One user said that for the first time in over ten years he was able to stop taking painkillers due to the pain in his knees and joints.”
Twenty-one test subjects have participated in the study in which the new shoe design has been tested and compared with traditional models. Here is test subject Ole Einar Brækken running on the treadmill. PHOTO: SINTEF
At the same time, Storholmen emphasizes that the connection between footwear, ergonomics and musculoskeletal disorders is complicated.
“We’re talking about quite complex causes, and we haven’t yet done long-term studies. But these are people who walk ten to twenty thousand steps a day, and good safety footwear can reduce the impact load. We are already seeing that it is possible to reduce the load, and over time this will have an impact.”
Benefits of an interdisciplinary project
The Lightfoot project has collaborated with the Norwegian company Wenaas Workwear, which supplies protective clothing and safety equipment to the Norwegian market. The shoes are manufactured by the Italian company Orion.
About the project:
Project title: Lightfoot
Duration: 2022-2025
Funding: Research Council of Norway with NOK 5.2 million
Project owner: Wenaas AS
Research partners: SINTEF and Orion Group
Project partners: Equinor, AkerBP and OneCo
“We’ve collaborated closely with the manufacturer in Italy, who has had to completely rethink the production method. They have been producing safety shoes for forty years and say they have never seen anyone tinker with so many elements at once,” says Storholmen.
This is a prototype of the new safety shoe. This pair has walked one million steps at one of Equinor’s locations. Photo: Kjellrun Johanna Eik, Equinor
He emphasizes that the results of the project are primarily based on a data-driven approach.
“SINTEF has contributed research methodology. In addition, this project would not have been possible if we had worked in a less interdisciplinary fashion than we do. We have involved researchers in physiology, biomechanics, industrial design and data analysis. This approach is key when working with an industry that is as set in its ways as this one. You have to see things from different perspectives to find solutions,” says Storholmen.
Aker BP, Equinor and OneCo are also partners in the Lightfoot project, which has received support from the Research Council of Norway.
