Drag Area of a Cross-Country Skier

The drag area CDA of three male cross-country skiers as a function of their velocity was determined from their retardation when they were gliding on roller-skis over a horizontal smooth asphalt surface in a subway. The results show that CDA is a slightly decreasing function of the skier’s velocity in the velocity range 5–11 m/s. The drag area of a skier was found to be 0.27 ± 0.03 m2 in a semi-squatting posture and 0.65 ± 0.05 m2 in an upright posture for an average size skier (weight 80 kg, height 1.75 m). The difference in the drag area between a normal outdoor suit and a tight-fitting ski suit was found to be as much as 30%. A skier keeping pace with a skier ahead will gain a reduction in drag of about 25 %. The leading skier in this study was found to have his drag reduced by approximately 3 % compared to what it would be if there were no skier pacing up with him. The skier behind hinders the skier ahead from generating to a full extent the vortexes behind himself or herself. These reductions are of course strongly dependent on the distance between the skiers.