He is a bilateral below the knee amputee as a result of meningococcal disease at the age of thirteen.

She won the Women's TRI-2 (above knee amputee) class, then successfully defended her TRI-2 World Champion title in 2011 and 2012.

The IPC defined this as: "Single above knee amputees and athletes with other impairments that are comparable to a single above knee amputation.

Single above- knee amputees with short residual limbs.

TRI 2 - Severe leg impairment,including above knee amputees.

At this time, competitors who were S9 classified tended to be above the elbow or above the knee amputees.

Double above knee amputee Richard Whitehead also runs in the T42 classification.

For below the knee amputees in this class, their ski boot may have their prosthetic leg built into it.

The classification includes cerebral palsy skiers classified CP5 and CP6, and double below the knee amputees.

Depending on the sense of balance, some above the knee amputees will choose to play without a prosthesis hopping on a single leg.