1. Sports Tech Research Centre, Mid Sweden University, Akademigatan 1, Östersund 831 25, Sweden e-mail:
2. Department of Surgical and Perioperative Sciences—Orthopaedics, University of Umeå, Umeå 901 87, Sweden e-mail:
3. Department of Orthopaedics, Östersunds Hospital, Östersunds sjukhus, Ortopedmottagningen, Östersund 831 83, Sweden e-mail: