If the shoe fits ...

A tester walks on Wei Kunlin's (left) foot pressure measure system. Tan Huiyuan / for China Daily

Domestic developers are racing to create customized footwear. Wang Kaihao reports.

Many envy Jamaican sprinter Usain Bolt's tailored golden running shoes and hope to customize their own footwear for form and function. That s why people are walking across a flat board in the lab of Wei Kunlin, an associate professor studying human motor control in Peking University's Department of Psychology. He quotes Chinese comedian Zhao Benshan's famous line from Selling a Crutch: "If you think your feet are OK, please take a few steps."

The test subjects are walking on a foot-pressure measuring device, Wei explains. "I'm testing the pressure distribution of their feet and measuring their gaits."

The device works in concert with 3D scanning and motor control systems to analyze the unique characteristics of individuals' feet.

He started the project in 2010 in hopes of contributing to medical testing. But while working with diabetes patients the following year, the 33-year-old realized the system could be used to develop customized soles and even shoes.

Diabetics often suffer from a complication known as a "diabetic foot ulcer". High blood sugar causes arteriosclerosis, which worsens the condition of the foot over time.

About 15 percent of diabetics will develop the ulcers, and about 10 percent of them will need amputations, Peking University First Hospital physician Yuan Geheng says.

"The ulcers are irreversible," Yuan says.

"So prevention is important. Some Western surgeons can prevent the ulcers through operations on foot muscles and tendons, but nobody has tried that in China."

Wei's answer is individualized insoles that are customized according to the data collected by his measurement system.

"The first step is to test the predictive power of using pressure to determine high-risk locations on the foot," he says.

"Any point with abnormal pressure is where an ulcer will likely develop. The specialized insoles can distribute the pressure from that point to the surrounding area to prevent damage."

About 100 of Yuan's patients have participated in the clinical tests, and the doctor says more samples are needed to ensure the idea is practical. "It will fill in a blank," he says.

"But it's possible many people will believe they won't get an ulcer if their feet look OK."

He says customized insoles will cost about 900 yuan ($143) on the market.

But the impact of Wei's methods may extend beyond diabetics to such people as amateur athletes.

Transportation company employee Zhao Wei has undertaken long-distance races for 20 years.

The 43-year-old Beijinger has participated in the Beijing Marathon every year since 2006 and runs up to 50 km a week in his spare time.

His lower legs often feel stiff and painful, so he asked Wei for help. "I once turned to cobblers to adjust my shoes," Zhao says. "But it didn't work."

Wei found Zhao's right foot arch is lower than normal and his left heel is abnormally shaped. So, Zhao got customized insoles and new running shoes.

"It's much better," Zhao says.

"If I continue to run with these problems, my feet might get a lot worse."

But Wei hopes to take his technology beyond patients and athletes to ordinary people. And he hopes to go past individualizing insoles to customizing shoes.

But that's easier said than done, says Shao Kai, who once led a team developing athletic shoes for Li-Ning and now manages a subsidiary of the company.

"It costs more than 200,000 yuan ($3,200) to develop a pair of running shoes for a professional athlete," the 32-year-old says.

"And it takes about four months to analyze the data and design the shoes, and another one to two months to readjust them after the athlete wears them. If individualized shoes cost two to three times more than average running shoes, some high-end customers might accept the price. But we don't have the technology to make the price that low."

However, Wei's work is paving the way for the day when customized shoes will become affordable to the average consumer.

"It could prevent many unnecessary injuries," Wei says.

Shao says: "The categorization of shoes in China's market is still coarse-grained. Sports shoes, for example, are basically sorted into soccer shoes, basketball shoes, tennis shoes and so on. That's not specific enough."

Some international brands have created several categories of shoes for every sport, Shao says.

Domestic manufacturers are starting to follow suit and Shao expects China will have similarly detailed categorizations in five to eight years.

Adidas has begun commercialized customization, Shao says. Although customers can't get shoes exclusively tailored to their feet, they can buy shoes based on several major parameters in gait patterns, such as step stability and foot width.

Wei puts it this way: "If three different models are designed for every parameter, that's nine types of shoes if we refer to two parameters. What will happen if we refer to three? We will have many more choices," Wei says.

"While a patient's feet might be unlike others' and, therefore, require comprehensive customization, other people's feet might have a few sets of general characteristics."

Wei believes the hardest part is the first step, which his method has overcome. "What we need is to make some models for ordinary people rather than making shoes for professional athletes," he says.

"China is the world's largest shoemaker. We have the whole production chain right here. So, it's likely China will achieve full customization before any other country."