The ranges of motion and relationship between the joints of the lower
extremities serve three purposes:

1) Propulsion
2) Energy absorption
3) Balance

There is a wide spectrum of ‘normal’ both within and between genders. Abnormal function can be de­scribed as a dysfunction of any of the three basic func­tions as described above. Abnormal function is usu­ally caused by disease, injury, deconditioning, aging, and is occasionally congenital.
Natural differences in bone length ratios, muscle at­tachment points, range of motion, flexibility, and align­ment will predispose individuals to excel at different sports. Recognizing the features of an individual’s nat­ural build will help to assess their potential for skiing and optimize their performance through adjustments to equipment and alignment. Just as some people are natural runners, there are those who are built to ski. Since the skiing public encompasses the whole spectrum of body types, most people will require some alterations in equipment and alignment to optimize their balance and technique.