1. Section of Sports Medicine, Department of Community Medicine and Rehabilitation, Umeå University, 901 87 Umeå, Sweden
2. Umeå School of Sports Sciences, Umeå University, 901 87 Umeå, Sweden
3. Department of Surgical & Perioperative Sciences, Umeå University, 901 87 Umeå, Sweden
4. Department of Physiology, Medical School, National and Kapodistrian University of Athens, 157 72 Athens, Greece