Digital Public Defence: Kristine Risum

MSc Kristine Risum at Institute of Health and Society will be defending the thesis “Physical activity and physical fitness in juvenile idiopathic arthritis” for the degree of PhD (Philosophiae Doctor).

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Øystein H. Horgmo, UiO.

The public defence will be held as a video conference over Zoom.

The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

Click here to participate in the public defence

Download Zoom here

Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.


Digital Trial Lecture – time and place

See Digital Trial Lecture.

Adjudication committee

  • First opponent: Professor Troels Herlin, Aarhus Universitetshospital
  • Second opponent: Professor Christina Helging Opava, Karolinska Institutet
  • Third member and chair of the evaluation committee: Professor II Reidun B. Jahnsen, University of Oslo

Chair of the Defence

Professor II Hilde Berner Hammer, University of Oslo

Principal Supervisor

Senior Consultant Helga Sanner, Oslo University Hospital


The aims of this study were to examine physical activity (PA) behavior and physical fitness in patients with juvenile idiopathic arthritis (JIA) who were diagnosed in the era of biologics and controls from the general population Further, to investigate the measurement properties of a submaximal treadmill test for clinical and research purposes.

The thesis has a comparative cross-sectional design, including a test-retest design to evaluate the reliability of the submaximal treadmill test. PA behavior was examined by objective and subjective measurements. Physical fitness was assessed with state-of-the-art methods. Additionally, the participants performed a submaximal treadmill test for the evaluation of criterion validity and reliability.

The overall PA levels were comparable between patients and controls, but patients had lower levels of vigorous PA. Patients participated in similar types of organized and unorganized PA as controls. Both patients and controls reported enjoyment as the most important PA facilitator.

Patients and controls had comparable cardiorespiratory fitness and body composition, while patients had lower muscle strength and bone mineral density. The use of biologic medication was a correlate for higher overall PA levels and lower sedentary time. No other disease variables were identified as correlates for PA or physical fitness. Higher vigorous PA was a correlate for higher cardiorespiratory fitness and muscle strength in patients.

The submaximal treadmill test was valid and reliable for research purposes on group level in patients, but not optimal for estimation of maximum oxygen uptake in individual patients.

Our findings are encouraging regarding PA behavior and physical fitness in patients with JIA. The results suggest that patients also should perform vigorous PA and bone- and muscle-strengthening activities at least three times per week according to PA recommendations for children in general, preferably through enjoyable activities.

Additional information

Contact the research support staff.

Published Jan. 29, 2021 11:14 AM - Last modified Feb. 15, 2021 10:17 AM