If you're driving through the Serra de Tramuntana and come across groups of shirtless athletes on skis with wheels on the ends and high, stiff boots on the sides, don't worry, you're not seeing things. They practice rollerskiing, better known as skiing on wheels, a technique similar to cross-country skiing. It's been around for over 80 years and has evolved in different ways until it became its own sport in the 1970s.
Most, if not all, cross-country ski teams practice rollerskiing during the off-season in order to carry out specific physical training as close as possible to winter skiing. In countries such as Norway, with a long tradition, specific facilities have been set up to allow the exercise on public roads. For this reason, these weeks it will be common to see them around.
The rollerski consists of two rectangular-shaped boards made of light wood or fibreglass-carbon fibre. The length is between 53 and 70 cm. The ends of the boards are fitted with rubber or plastic covered wheels (between 2 and 7 cm wide) mounted on ball bearings.