Telemark skiing is a term use for skiing using the Telemark turn, which is a technique invented by Norwegian Sondre Norheim. It is also known as "free heel skiing." Unlike alpine skiing equipment, the skis used for telemarking have a binding that only connects the boot to the ski at the toes, just as in cross-country skiing. Telemark turns are led with the heel flat on the outside ski, while the inside ski is pulled beneath the skier's body with a flexed knee and raised heel. The skis are staggered but not quite parallel, and 50% to 80% of the body weight is distributed on the outer ski, depending on snow conditions. The relationship between the two skis often is metaphorically understood as one longer, but curved ski. The reason for this metaphor is that it is this curve that makes the turn ratio of the skier and defines the relationship between the two skis.