The impact of significant constraints on expertise development: a comparison between world-class cross-country skiers and freeskiers - Aalberg, M.; Roaas, T. V.; Aune, M. A.; Bjerke, Ø; Aune, T. K. (9th International Congress on Science and Skiing, March 18 - 22, 2023, Saalbach-Hinterglemm, Austria, 2023)