Back in 2016, a group of frustrated restaurant and hospital CEOs came to Heeluxe to complain about their distrust of current shoe traction tests. They wanted a test that could accurately predict if a shoe would reduce slip and fall injuries in their unique office environment. The Heeluxe scientists are always into a challenge, especially if the outcome is better shoes. Little did we know how difficult making the best traction test in the world would be.
Multiple published research articles have highlighted the problems with commonly used traction tests, such as the Brungraber Mark IV and TM144 test standard (see links below). In response to this, Heeluxe developed a human based traction test that was used extensively from 2012-2014. The problem with testing traction on humans is that the testers would get tired quickly and it’s very hard to prevent them from getting injured. After the meeting in 2016, we began planning a machine, called KITT, that replicated a human walking step. This lead to…
Challenge of Shoe Traction Testing #1: Human Movement is Complex
Every time a human foot hits the ground there are forces moving in every direction—and it happens FAST! Luckily the ankle and foot from our Time Machine durability test could replicate the forces and angles of normal human movement. The challenge for our engineers was making the foot hit the ground at the exact same speed with the exact same forces as a human. Once the framework of KITT was built, we spent over 2 years tuning KITT so that the foot strike was the same as a human. In 2021, we realized that it wasn’t good enough, resulting in 6 more months of fine tuning to make sure that KITT replicated an average walking stride.
Challenge of Shoe Traction Testing #2: Slipping and Sticking are Very Different
Most of the shoe traction tests measure how well a shoe outsole sticks, until it finally releases or “slips”. These tests do not re-create the slip and fall mechanics of a human. Luckily, Kurt Beschorner, Indian Iraqui, and their team of researchers published a wonderful series of research papers that analyzed how people slip and fall. At Heeluxe, we digested this information and tuned KITT so that it will slip and fall just like a human being would if the shoe outsole does not have sufficient traction. Tuning this was a big challenge, but one challenge was even bigger:
Challenge of Shoe Traction Testing #3: Contaminants Make for Dirty Data
Rarely do shoes slip on smooth, clean, and dry surfaces. Contaminants on the floor reduce traction and increase the likelihood of slips. Most standardized tests analyze a few contaminants, like water, oil, or soap. This represents a very small proportion of the contaminants that people slip on in the real world. We’ve collected data on so many contaminants that cause slips. Some of our favorites are: Shrimp, Dusty Basketball court, Cornmeal, raw ground Beef (ew), fine Gravel, and French Fries. KITT allows us to test any contaminant on any floor surface. However, standardizing the amount of the contaminant, how the contaminant is applied to the floor surface, and even the temperature of the contaminants can change a traction score. Making contaminants perform the same for every shoe that is tested is the biggest challenge Heeluxe has faced in our quest to make a better shoe traction test.
There are many challenges to having a shoe achieve the same traction score any time it is tested on a given surface with a certain contaminant. But that is what footwear brands and employers deserve. Until a better traction test comes along, Heeluxe and KITT will continue tackling the challenges of traction testing to help you make (and wear) better shoes.
Interested in traction testing, or want to talk about the craziest contaminants we have tested? Contact Heeluxe at [email protected].