Children and adolescents with juvenile idiopathic arthritis (JIA) in most parts of the world have decreased muscle strength, bone health and well-being compared to healthy peers [1–8]. The disease can affect school performance, physical training, family life, and activities in leisure time with peers [9–11]. Kimura et al. declare in a study from 2008 that pain is one of the major symptoms and limits the activities, disrupts school attendance and contributes to psychosocial distress .
The last decade has seen the introduction of biological drugs, e.g. anti-tumor necrosis factor alpha (anti-TNFα) also for paediatric rheumatic disorders [13, 14]. The medical effect of anti-TNF is especially high in children with polyarticular onset of JIA [13, 14]. In subjects with JIA the effects are described as improvement in functional ability, health-related quality of life, pain, sleep quality and daily participation and in terms of less flares or inflammatory active joints [15–17]. Anti-TNFα drugs are effective, safe and well tolerated in children with JIA [14–19].
Despite the use of biological agents, pain is reported as the major symptom of the disease, and joint pain is the leading cause of disability in this disease . The authors describe pain perception as multifactorial and therefore require “a bio-psychosocial model that includes the individual’s age, developmental status, coping ability, mood, stress levels, and environmental and family factors, in addition to disease status and severity” .
Physical activity is important from a health perspective, especially in the subgroups with the polyarticular and extended oligoarticular categories [1, 2, 12, 17, 20]. Different physical activities have been studied such as jumping with a rope (rope-skipping) and exercise programs in water [4, 6, 7, 21–24]. Jumping has influence on bone health and foot orthotics can significantly improve pain, speed of ambulation, and self-rated activity and functional ability [23, 25].
Exercise programs with weight bearing exercises have been shown to improve both muscle strength and bone mass [6, 22, 23]. The exercise programmes in these studies were at different intensity levels and of different duration and physical activity in leisure time was not fully documented [4, 6, 22]. Takken showed that also cardiovascular fitness was decreased in children with JIA compared to healthy peers and point out the importance of cardiovascular fitness and motor performance as a part of total well-being . Muscle strength is an important part in a fitness programme; muscle weakness in children with JIA is reported in many studies since the 1990s [2, 8, 9]. There is, however, a lack of knowledge about physical exercise levels and the impact on pain and well-being.
Physical fitness is described as a state of well-being with energy to participate in a variety of physical activities . Frankala-Pinkham et al. stress the importance to incorporate more strategies to increase fitness, physical activity, and participation in the rehabilitation programme to improve quality of life (QoL) . Questions concerning well-being and the impact of social and psychological functioning are well covered in the Child Health Questionnaire (CHQ) [28–30]. A couple of studies have reported that children with JIA after exercise interventions have less physical impairment or discomfort but report low levels of psychosocial abilities such as self esteem, psychosocial functioning and high levels of pain [21, 22, 25]. This seems to be a pattern for children with different chronic diseases or disabilities [31, 32].
At our hospital the children with JIA attend the hospital regularly for physical training, which is time-consuming and costly both for the families and the health care system. An easy-to-handle home-based exercise programme making the patient less dependent on the physical therapist was needed, which was the impetus for this study. The aim of the study was to evaluate muscle strength, grip strength, physical fitness and well-being in a cohort of children and adolescents with JIA and the effects of a home-based exercise programme.