They are generally individuals who have amputations, post polio or hemiplegia. Three trackers use a fullsize ski and outriggers giving them three points of contact on the snow. Four Track Four tracking is for individuals with involvement of the lower extremities. This may include individuals with cerebral palsy, spina bifida, spinal cord injuries, multiple sclerosis or those who have lower extremity amputations. Almost anyone who walks with canes or crutches may ski four track using outriggers.
Outriggers are adapted forearm crutches with ski tips mounted on the bottom.
They aid the skier in stability and turning. Two skis and two outriggers provide the four tracker with four points of contact on the snow. The mono-ski was developed for individuals who ski in a sitting position. A mono-skier should have good upper body strength, balance and trunk mobility. The skier sits in a molded shell mounted above a single ski.