Guest pro Erin heads out to the giant slalom course to meet Nykeem and Sarah, a tenacious young para alpine skier. Sarah was born with fibular amelia, and she had one lower leg amputated early in life. Since she can't bend her ankles, she uses her knees and hips when turning. Dr. Heather explains the two drag forces that work against skiers: air resistance slows you down and the faster you are moving, the stronger the air resistance. By tucking her body, Erin reduces her surface area and reduces the air resistance.  The friction of skis against the snow can also slow you down, so carving her skis at an angle around the gates allows Erin to reduce friction resistance. We also learn why the body shivers in cold air. Para-alpine skiing began after World War II when veterans with battle injuries found ways to ski despite their disabilities. The first International para-alpine competition was held in France in 1974.