Fencers often suffer from knee, ankle and foot injuries.
Fencing moves like lunges and parries require sudden wrist and leg movements that can damage an athlete's limbs over time.
To enhance fencers' leg and foot protection, the Hong Kong Research Institute of Textiles & Apparel developed a pair of asymmetric shoes.
Hong Kong fencing team member Lin Po-heung wore them in the 2016 Rio Olympics.
They were designed to be asymmetric as fencing involves moves and postures that exert different forces on the left and right foot.
The institute’s director Gloria Yao said many fencers suffer from knee pain and other injuries because of the uneven distribution of pressure.
"Fencers always repeat the same movements. The force exerted by the lunge onto the heel of the lead foot is up to seven times the fencer’s body weight," she said.
"The trailing foot also wears out the shoe easily. A pair of ordinary fencing shoes usually wears out in two to four weeks."
Hi-tech invention
After learning about the fencer footwear issue from the Hong Kong Sports Institute, Ms Yao and her team came up with their design, with assistance from a $2.79 million grant from the Innovation & Technology Fund.
They measured the athletes' feet with 3D scanning machines.
Motion analyses and biomechanical tests were then conducted to evaluate the pressure exerted by different fencing moves on leg and foot joints and muscles.
They came up with the asymmetric design after the tests showed the vertical movement of the lunging lead leg exerted a greater pressure than that of the other leg, which maintains a horizontal position while dragging behind.
To better cushion the pressure points, shock-absorbing materials were inserted into the midsole and insole for the lead foot.
Special scuff-resistant materials were added to the trailing foot's shoe.
While natural rubber was used for the outsole to keep the shoe light and durable, its other parts were made with thermal insulation materials for more comfort.
Improved performance
The shoes are now used by the Hong Kong fencing team for training and competitions.
Fencer Kimberly Cheung's knee injury has improved since she started wearing the asymmetric shoes.
She began to feel pain in her knee four years ago after playing the sport for 12 years.
"The shoes are comfortable and light. They help me move faster and easier. The heel cushions provide much more protection than the ones I wore before. The shoes also help me achieve a better balance in the feet."
The shoes won a silver medal in the 45th International Exhibition of Inventions - Geneva in March.
The institute plans to develop asymmetric shoes for badminton and table tennis players next.
