How many times are allowed to change skis in the cross-country skiing 30 km event?

Cross-country skiing competition involves two technical rules.

They are traditional technology and freestyle technology.

Freestyle skiing is a snow sport in a special ski resort by using snowboarding and skiing poles as tools and completing a series of prescribed and optional actions. It is bred and developed on the basis of alpine skiing, and consists of three independent projects: aerial skills, snow skills and snow ballet. Freestyle technique has restrictions on players' kicking posture. According to the standard, the total number of events in the competition should be half of the traditional design style and half of the freestyle. The standard cross-country skiing competition route is divided into uphill starting point and downhill friendship ending point, each accounting for one-third of the whole journey. The highest point of the ski resort shall not exceed 1800 meters. Snowboards should be marked.

According to the requirements, the skis worn by the players from the starting point to the finishing point must contain the marks drawn by the referee when considering, because the bottom edge of the skis is coated with snow wax, which is very smooth and conducive to sliding. This sign is to prevent players from changing skis halfway. The two technical standards involved in cross-country skiing competition are traditional technology and freestyle technology.

The traditional technology stipulates that players can't have all the ice-pedaling (that is, side pedaling) postures during the whole competition (including sliding with both feet alternately, sliding at the same time, stepping on their feet while sliding, turning downhill and so on). ). freestyle technique has restrictions on players' kicking posture. According to the standard, the total number of events in the competition should be half of the traditional design style and half of the freestyle.