It probably started in Austria and Germany in the 1920’s when cross-country skis were equipped with tiny rollers to make them usable without snow to glide on. Another early roller ski model consisted of two modified scooters. Since then many models of roller skis have been conceived, constructed, used and forgotten. They have been between circa 60 to over 200 centimeters long. They have had 2-5 wheels per ski, solid wheels mostly of rubber, or solid or inflatable tires on metal or plastic rims. Wheel diameters have ranged from a few centimeters to around 30. The roller ski shafts or frames have been made of wood, metal, plastic, glass- or carbon-fiber, or combinations of these materials. The boots and bindings used have generally been those of cross-country skiing although special roller ski boots and bindings have been developed in later years. The poles used are cross-country ski poles with hardened tips to resist the greater wear from the road surfaces.
Today, a standard roller ski for the classic technique has a wheelbase of a little over 70 cm, an aluminum or composite shaft with at each end one solid rubber wheel circa 45 mm wide and 70 mm in diameter. A free technique roller ski has typically a wheelbase of around 60 cm, an aluminum or composite shaft with at each end one wheel measuring 24 mm in width and 100 mm in diameter with an aluminum rim and a tire of solid rubber.
Roller skis have been, and today still are, mainly used as training devices for cross-country ski athletes, but in the last decades roller skiing has gained a position as a sport of its own, and has also become an enjoyable and very efficient fitness activity that develops the practitioner’s balance and coordination too. It is an open-air mobile and inexpensive gym on wheels, offering great exercise and often wonderful experiences of nature. It is, however, a dangerous sport since falling on hard roads at some speed, and with hands and feet locked up by roller skis and poles, can have severe consequences and the roller skier should wear protection equipment, at least a helmet.