[1
]
Department of Surgical and Perioperative Sciences, Sports Medicine, Umeå University,
Umeå, Sweden.
[2
]
Department of Community Medicine and Rehabilitation, Geriatric Medicine, Umeå University,
Umeå, Sweden.
[3
]
Football Research Group, Division of Community Medicine, Department of Medical and
Health Sciences, Linköping University, Linköping, Sweden.