According to whiteturf.ch:
Back in the days of the first skijoring race in 1906, many things were quite different to today. The race followed a route by road from St. Moritz to Champfèr, and the participants did not start all together, but individually at one-minute intervals. Philip Mark, President of the Alpina Ski Club, and his Irish chestnut gelding, Blitz, were the fastest, taking 20 minutes and 22 seconds to complete the almost ten kilometre stretch. Ever since skijoring was transferred to the racecourse, it has been run like any other horse race – in a group, horse against horse, skier against skier. This demands a great deal of skiing prowess on the part of the athletes, as well as firm control of their four-legged partners.
Read more: History of skijoring in St. Moritz