B-Peg Snowboarding Prosthesis: Liang-Ti Tan’s Leg Tested at Val Thorens

Most below-knee prostheses are designed for walking, and a snowboard asks for something very different: deep flex at the ankle and knee, constant shifts of weight from heel to toe, and a body that rotates over the board through every turn. B-Peg was one answer to that problem, a mechanical prosthetic leg made specifically for snowboarding and tested on the slopes of Val Thorens in January 2014.

The B-Peg team: designer, maker and rider

B-Peg was a collaboration of three. Liang-Ti Tan designed the prosthesis, Boers & Co FijnMetaal fabricated the parts, and snowboarder Jos Zaal was the rider who put it to the test. Tan documented the work on his YouTube channel, where the second version appears as “B-Peg Prosthetic Leg for Snowboarding V2”.

The idea was to build the leg around one sport instead of adapting an everyday walking prosthesis. The project photos show the mechanical prosthesis close up, on the snow and paired with a snowboard.

Why snowboarding needs a different prosthesis

Researchers have studied the same challenge. In a paper on a novel below-knee prosthesis for snowboarding, Dutch engineers Sander Minnoye and Dick Plettenburg started from range-of-motion analyses of snowboarders. Their point was simple: standard below-knee prostheses are built for normal walking, so a rider using one cannot rotate and flex the way able-bodied snowboarders do. A sport-specific design aims to give back that movement.

The same thinking runs through adaptive winter sport. Ottobock’s ProCarve, a prosthesis for skiers, uses a sports knee joint that unlocks so athletes can sit on chairlifts, and a hydraulic damper borrowed from motorcycling that controls flexion and absorbs bumps. Athletes pump air into the spring to set the stiffness for the day’s snow. The International Paralympic Committee approved it for competition after safety studies.

Testing B-Peg at Val Thorens

For the January 2014 trial the team went to Val Thorens in the French Alps, a high-altitude resort. The village sits at about 2,300 metres in the commune of Les Belleville in Savoie, and its skiable peaks include Cime de Caron at 3,200 metres. Val Thorens is part of Les 3 Vallées, a linked ski area with more than 600 kilometres of slopes, and its season usually runs from mid-November to early May.

The video shows the second version of the prosthesis in use on the snow, the stage where a design meets real turns and changing conditions.

Adaptive snowboarding today

B-Peg belongs to a wave of projects that changed what amputee riders can do on snow. Para snowboarders now compete at the Paralympic Winter Games, and athletes such as China’s Kaiyang Liu, who lost a leg at the age of five, raced at Beijing 2022. Prosthetic fit is personal, so riders work with their prosthetist and test new equipment on easy terrain first.

For more stories of riders and equipment, see protective equipment and its limits and another specialised snowboard-and-ski film setting.

Related reading

• Michelle Salt’s Early Competitive Para-Snowboarding Story
• Maria Leijerstam’s Tricycle Journey to the South Pole
• Ava’s Early Snowboard Ride at Mammoth
• A Snowy Garden Surprise for Mason and Melodie Williams

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