1. Division of Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
2. Department of Clinical Sciences, Respiratory Medicine and Allergology, Lund University, Lund, Sweden
3. Department of Community Medicine and Rehabilitation, Unit of Research, Education and Development, Umeå University, Östersund, Sweden
4. Unit of Research, Education and Development, Östersund Hospital, Östersund, Sweden
5. Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden