Motor development in children 0-2 years pre- and post-LTX, a prospective study.

To determine prospectively gross and fine motor development of children <2 years of age, who undergo LTX. In this prospective study, children aged <2 years who undergo LTX were tested using the motor scale of the Bayley Scales of infant and toddler development, 3rd edition Dutch version. Testing was done during screening pre- and post-LTX: at the time of hospital discharge (2-6 weeks), at 3 months, 6 months, and 1 year. Z-scores were calculated. Twenty-nine children participated in this study, 14 boys, median age 6 months, at screening for LTX. Gross motor skills were delayed pre-LTX (Z-score -1.3). Fine motor skills were normal (Z-score 0.3). Immediately post-LTX, both skills reduced, and at 1 year post-LTX, gross motor skills Z-score was -1.0 and fine motor skills Z-score 0.0. Both gross and fine motor skills Z-scores decline post-LTX and tend to recover after 1 year, gross motor skills to low normal and fine motor skills to normal levels. Monitoring of gross motor development and attention on stimulating gross motor development post-LTX remains important, to enable participation in physical activity and sport for health benefits later in life.

Physical activity and aerobic fitness in children after liver transplantation.

To determine physical activity (PA), aerobic fitness, muscle strength, health-related quality of life (HRQOL), fatigue, and participation in children after liver transplantation. Children, 6-12 years, at least one year after liver transplantation, participated in this cross-sectional study. Measurements: Time spent in moderate to vigorous PA (MVPA) was measured using an accelerometer, and aerobic fitness (VO2 peak ) was measured by cardiopulmonary exercise testing. Muscle strength was measured by hand-held dynamometry. Fatigue was measured using the multidimensional fatigue scale, and HRQOL with the Pediatric Quality of life Core scales and leisure activities was measured using the Children's Assessment of Participation and Enjoyment. Outcomes (medians and interquartile range (IQR)) were compared to norm values. Twenty-six children participated in this study (14 boys, age 9.7 years, IQR 7.7;11.4). Children spent 0.8 hours/d (IQR 0.6;1.1) on MVPA. One child met the recommendation of at least 1 hour of MVPA every day of the week. Aerobic fitness was similar to norms (VO2 peak 1.4 L/min , IQR 1.1;1.7, Z-score -0.3). Z-scores of muscle strength ranged between -1.4 and -0.4 and HRQOL and fatigue between -2.3 and -0.4. Participation was similar to published norms (Z-scores between -0.6 and 0.6). Young children after liver transplantation have similar MVPA patterns and aerobic fitness compared to published norms. Despite lower HRQOL, more fatigue, and less muscle strength, these children have similar participation in daily activities. Although children do well, it remains important to stimulate PA in children after liver transplantation in the context of long-term management.

Muscles in motion: a randomized controlled trial on the feasibility, safety and efficacy of an exercise training programme in children and adolescents with juvenile dermatomyositis.

OBJECTIVE: To study for the first time in a randomized controlled trial the feasibility, safety and efficacy of an exercise training programme in children and adolescents with JDM. METHODS: Patients were randomly assigned to the Intervention Group (IG; n = 14) or Waiting Control Group (WCG; n = 12). The intervention comprised an individually tailored 12-week home-based exercise programme of treadmill interval training and strength exercises. The efficacy of the IG over usual care (WCG) was examined with mixed linear regression (intention-to-treat). Effect sustainability during 12 weeks follow-up was also examined. RESULTS: Seventy-five percent of the participants completed the intervention. Reasons for discontinuation were motivation/fatigue, recurrent infections and increasing physical complaints. No hospitalizations occurred and immune suppressive therapy remained stable or decreased in the patients who participated in the intervention. The estimated marginal means after the intervention period were significantly in favour of the IG compared with the WCG for standing long jump distance [difference between groups (95% CI): 13 cm (2-23)], the 30-s number of push-ups [8 (3-13)] and sit-ups [4 (0.4-8)], and the parent Childhood Health Assessment Questionnaire 30 + 8 score [-0.13 (-0.24 to - 0.01)] and effects sustained at follow-up. A trend was seen for the maximal oxygen uptake divided by body mass during maximal exercise treadmill testing; the IG scored 3.0 ml/kg/min (-1.3 to 7.3) higher compared with the WCG. Other outcomes (e.g. isometric muscle strength and perception of fatigue) did not differ between IG and WCG. CONCLUSION: Exercise training is of value in the clinical management of JDM.

Decreased Muscle Strength in Children With Repaired Tetralogy of Fallot: Relation With Exercise Capacity.

Background The aim of this study is to describe muscle strength in pediatric patients with repaired tetralogy of Fallot compared with healthy peers and to analyze the correlation between muscle strength and peak oxygen uptake, exercise capacity (mL/min). Methods and Results A prospective, cross-sectional study was carried out in the University Medical Center Groningen between March 2016 and December 2019, which included 8 -to-19-year-old patients with repaired tetralogy of Fallot. Exclusion criteria comprised the following: Down syndrome, unstable pulmonary disease and severe scoliosis affecting pulmonary function, neuromuscular disease, and mental or physical limitations that prohibit the execution of the functional tests. Muscle strength was compared with 2 healthy pediatric cohorts from the Northern Netherlands. Handgrip strength, maximal voluntary isometric contraction, and dynamic muscle strength in correlation with peak oxygen uptake, exercise capacity (mL/min) were the main outcomes of the study. The 67 patients with repaired tetralogy of Fallot (42% female; aged 12.9 [interquartile range, 10.0-16.3] years old) were compared with healthy children. The patients showed reduced grip strength (z-score [mean±SD] -1.5±1.2, P<0.001), and total muscle strength (z-score -0.9±1.3, P<0.001). Dynamic strength (Bruininks-Oseretsky test) was significantly reduced (z-score -0.3±0.8, P=0.001), but running, speed, and agility were normal (z-score 0.1±0.7, P=0.4). Univariate correlation analyses showed strong correlations between absolute peak oxygen uptake, exercise capacity (mL/min), and muscle strength (grip strength r=0.83, total muscle strength r=0.88; P<0.001). In multivariate analyses, including correction for age and sex, total muscle strength (B 0.3; P=0.009), and forced vital capacity (B 0.5; P=0.02) correlated with peak oxygen uptake, exercise capacity (mL/min), independent of conventional cardiovascular parameters. Conclusions Children with repaired tetralogy of Fallot show reduced muscle strength, which strongly correlated with their exercise performance.

Muscle strength is reduced in children with pulmonary arterial hypertension.

Muscle strength is decreased in adults with pulmonary arterial hypertension (PAH). We aim to investigate muscle strength in children with PAH in relation to a cohort of healthy children, and investigate correlations with disease severity markers. This prospective study included children with PAH aged 4-18 years, who visited the Dutch National Referral Center for Pulmonary Hypertension in Childhood between October 2015 and March 2016. Muscle strength was assessed using handgrip strength and maximum voluntary isometric contractility (MVIC) of four peripheral muscles. Dynamic muscle function was evaluated with the Bruininks-Oseretsky test of motor proficiency (BOT-2). These measurements were compared with those in two cohorts of healthy children and correlated with 6-minute walk distance (6MWD), World Health Organization functional class (WHO-FC), N-terminal pro-brain natriuretic peptide (NT-proBNP), and time since diagnosis. Eighteen children with PAH aged 14.0 [interquartile range: 9.9-16.0] years showed reduced muscle strength. Handgrip strength z-score -2.4 ± 1.2, p < 0.001, total MVIC z-score -2.9 ± 1.2, p < 0.001, and BOT-2 z-score -1.0 ± 0.9, p < 0.001. 6MWD (67 ± 11% predicted) correlated with most muscle measurements (r = 0.49-0.71, p = 0.001). Dynamic muscle function (BOT-2) differed between WHO-FC, whereas handgrip strength and MVIC did not. NT-proBNP and time since diagnosis did not show significant correlations with muscle strength measurements. Muscle strength was significantly reduced in children with PAH and correlated with 6MWD, but not with disease severity markers WHO-FC and NT-pro-BNP. The nature of this reduced muscle strength is yet unclear, but its occurrence in children with seemingly mild or well-controlled PAH supports the concept of PAH being a systemic syndrome involving peripheral skeletal muscles.

Changes in body size and body composition in survivors of childhood cancer: seven years follow-up of a prospective cohort study.

BACKGROUND & AIMS: Cancer treatment is known to have impact on nutritional status, and both underweight and overweight have been reported in several studies in survivors. A limitation of most studies is that they relied on retrospective data or were limited to a subgroup of patients. The current study aims to describe changes in body size and body composition prospectively seven years after diagnosis in a heterogeneous sample of childhood cancer survivors and to evaluate associated factors. METHODS: The study population consisted of children diagnosed with hematological, solid and brain malignancies aged 0-18 years at diagnosis. Data of body size, body composition, and associated factors were collected at diagnosis, one year and seven years after diagnosis. RESULTS: In the total cohort mean BMI z-score increased during treatment. In children with hematological and brain malignancies BMI z-score continued to increase after end of treatment leading to quadrupling of the prevalence of obesity seven years after diagnosis. BMI at diagnosis (ß = -0.34, P = 0.007) and maternal BMI (ß = 0.25, P = 0.046) were associated with the increase in BMI z-score. Mean fat mass (FM) z-score, already high at diagnosis, increased during treatment in children with hematological and brain malignancies and evened out during follow-up. Changes in FM z-score were predicted by type of malignancy (hematologic malignancy versus solid tumor ß = 0.48, P = 0.008; brain tumor versus solid tumor ß = 0.45, P = 0.012). Mean fat free mass (FFM) z-scores started low at diagnosis, particularly in patients with brain tumors, increased during treatment in patients with solid and brain malignancies, though decreased in children with hematological malignancies. At 7 years follow-up a clear increase to normal was seen. Age at diagnosis (ß = 0.43, P = 0.004) and initial FFM (ß = -0.49, P = 0.001) were found to be significant predictors for changes in FFM z-scores. CONCLUSIONS: The finding that the once obtained extra weight and FM during treatment persisted after termination of treatment in children with hematological and brain malignancies, stresses the importance to create awareness about the risk of developing overweight in children during cancer treatment.

Physical and Psychosocial Health in Pediatric Uveitis Patients.

BACKGROUND: To investigate the possible associations between childhood noninfectious uveitis and cardio-respiratory fitness, physical activity, health related quality of life and fatigue. METHODS: Cross-sectional analysis of 23 patients with noninfectious uveitis, aged 8-18 years. BMI, exercise capacity, muscle strength and physical activity were measured. Health-related quality of life and fatigue were assessed. The results were compared to standardized values for age matched healthy children. RESULTS: Twenty-three patients were included. Children with uveitis had a higher bodyweight and body mass index. Children with uveitis had lower cardio-respiratory fitness and they were less physically active, but they experienced a normal quality of life and normal fatigue. Parents of children with uveitis reported a lower quality of life and more fatigue for their children than parents of healthy children. CONCLUSION: Our study indicates that children with noninfectious uveitis are at risk of developing lower physical and psychosocial health.

Dutch juvenile idiopathic arthritis patients, carers and clinicians create a research agenda together following the James Lind Alliance method: a study protocol.

BACKGROUND: Research on Juvenile Idiopathic Arthritis (JIA) should support patients, caregivers/parents (carers) and clinicians to make important decisions in the consulting room and eventually to improve the lives of patients with JIA. Thus far these end-users of JIA-research have rarely been involved in the prioritisation of future research. MAIN BODY: Dutch organisations of patients, carers and clinicians will collaboratively develop a research agenda for JIA, following the James Lind Alliance (JLA) methodology. In a 'Priority Setting Partnership' (PSP), they will gradually establish a top 10 list of the most important unanswered research questions for JIA. In this process the input from clinicians, patients and their carers will be equally valued. Additionally, focus groups will be organised to involve young people with JIA. The involvement of all contributors will be monitored and evaluated. In this manner, the project will contribute to the growing body of literature on how to involve young people in agenda setting in a meaningful way. CONCLUSION: A JIA research agenda established through the JLA method and thus co-created by patients, carers and clinicians will inform researchers and research funders about the most important research questions for JIA. This will lead to research that really matters.

Measuring Physical Activity in Juvenile Idiopathic Arthritis: Activity Diary Versus Accelerometer.

OBJECTIVE: (1) To determine convergent validity of an activity diary (AD) and accelerometer (Actical brand/Phillips-Respironics) in measuring physical activity (PA) in children with juvenile idiopathic arthritis (JIA). (2) To determine how many days give reliable results. (3) To analyze effects of correcting accelerometer data for non-wear. METHODS: Patients with JIA (8-13 yrs) were recruited from 3 Dutch pediatric rheumatology centers. PA was assessed for 7 days with an AD and accelerometer, and was expressed as mean min/day of rest, light PA (LPA), moderate to vigorous PA (MVPA), and PA level (PAL). To analyze convergent validity, intraclass correlation coefficients (ICC) were calculated and paired sample Student t tests were performed. The required number of days to achieve reliable results was calculated using the Spearman-Brown prophecy formula. RESULTS: Convergent validity between AD and accelerometer was moderate for rest and PAL (ICC 0.41). ICC for LPA and MVPA were < 0.24. AD overestimated PAL and MVPA compared with the accelerometer. Wearing the accelerometer 7-19 days gave reliable PA estimates on group and individual levels. For the AD, 13-36 days were needed. Adjusting accelerometer data for non-wear resulted in a clinically relevant higher mean number of min/day spent in LPA (effect size 1.12), but not in MVPA (effect size 0.44). CONCLUSION: Convergent validity between AD and accelerometer is moderate to poor. In children with JIA, 1-week assessment with an accelerometer is sufficient to measure PA (all levels) reliably. On an individual level and for clinical use, 3 weeks are required. Additional use of AD enables correction for non-wear of accelerometer data.

Internet Program for Physical Activity and Exercise Capacity in Children With Juvenile Idiopathic Arthritis: A Multicenter Randomized Controlled Trial.

OBJECTIVE: To determine the effects of Rheumates@Work, an internet-based program supplemented with 4 group sessions, aimed at improving physical activity, exercise capacity, health-related quality of life (HRQoL), and participation in children with juvenile idiopathic arthritis. METHODS: Patients were recruited from 3 pediatric rheumatology centers in The Netherlands for an observer-blinded, randomized controlled multicenter trial. Physical activity level, time spent in rest, light, and moderate-to-vigorous physical activity (MVPA) were recorded in a diary and with an accelerometer, before intervention, after intervention, and at followup after 3 and 12 months (intervention group only). Exercise capacity was assessed using the Bruce treadmill protocol, HRQoL was assessed with the Pediatric Quality of Life Inventory generic core scale, and participation in school and in physical education classes were assessed by questionnaire. RESULTS: The intervention group consisted of 28 children, and there were 21 children in the control group. MVPA, exercise capacity, and participating in school and physical education classes improved significantly in the intervention group. HRQoL improved in the control group. No significant differences were found between groups. The effect of Rheumates@Work on physical activity and exercise capacity lasted during the 12 months of followup. Improvements in physical activity were significantly better for the cohort starting in winter compared to the summer cohort. CONCLUSION: Rheumates@Work had a positive, albeit small, effect on physical activity, exercise capacity, and participation in school and physical education class in the intervention group. Improvements lasted for 12 months. Participants who started in winter showed the most improvement. Rheumates@Work had no effect on HRQoL.

Fatigue in patients with juvenile idiopathic arthritis: A systematic review of the literature.

OBJECTIVE: To perform a systematic review of the current literature on studies related to fatigue in children with JIA. We studied the measurements that were used to assess fatigue and we focused on three outcome measurements, namely, (1) the prevalence of fatigue in JIA patients, (2) the determinants of and associations with fatigue in JIA patients, and (3) the impact of fatigue in JIA patients on daily life. METHODS: A search was conducted in the electronic databases Pubmed and Embase from January 1, 2000 until August 27, 2015. The quality in prognostic factors (QUIPS) tool was used to assess the risk of bias (ROB) in the selected studies, focused on the outcome fatigue. Of all, two authors independently judged the ROB. RESULTS: A total of 15 studies were included in this review. To assess fatigue, two unidimensional and three multidimensional scales were used, which hampered comparison. Fatigue was reported to be present in 60-76% of the patients with JIA and was related to time of day, disease activity, pain, psychosocial factors, and sleep. Minor consequences for daily life were found, though this was not studied extensively. CONCLUSION: Fatigue is common in patients with JIA. The cause reflects a complex interplay of different factors. Based on results from this review and its body of knowledge, a conceptual model for fatigue in patients with JIA is proposed. Consensus is needed for future studies on how to assess fatigue. We promote the use of a combination of unidimensional and validated multidimensional measurements.

Physical activity in children with Juvenile Idiopathic Arthritis compared to controls.

BACKGROUND: To compare physical activity (PA) in children with juvenile idiopathic arthritis (JIA) with controls and to analyse the effect of disease specific factors on PA in children with JIA treated according to current treatment regimes. METHODS: PA was measured with a 7-day activity diary and expressed as physical activity level (PAL). Moderate to vigorous physical activity (MVPA) (hours/day) and sedentary time (hours/day) was determined. In children with JIA, medication, the number of swollen and/or painful joints, disease activity, functional ability, pain and well-being was determined. Multivariate regression analysis was performed to analyze differences in PA between JIA and controls, adjusted for influences of age, gender, season, Body Mass Index (BMI) and to analyze predictors of PA in JIA patients. RESULTS: Seventy-six children with JIA (26 boys and 50 girls, mean ± SD age 10.0 ± 1.4 years) and 131 controls (49 boys and 82 girls, mean ± SD age 10.4 ± 1.2 years) participated in this study. Children with JIA had a significantly lower PAL (0.10, p = 0.01) corrected for age, BMI, gender and season. They spent less time in MVPA (0.41 h/day, p = 0.06) and had a significantly higher mean time spent in sedentary activities (0.59 h/day, p 0.02) compared to controls. The activity level of children with JIA was related to age, gender, season, feeling of well-being and pain. CONCLUSION: Children with JIA have a lower PAL, spent less time in MVPA and spent more time on sedentary activities compared to controls despite current medical treatment and PA encouragement. TRIAL REGISTRATION: Data of the children with JIA are from the Rheumates@work study ISRCTN92733069 .

Design and acceptance of Rheumates@Work, a combined internet-based and in person instruction model, an interactive, educational, and cognitive behavioral program for children with juvenile idiopathic arthritis.

BACKGROUND: Juvenile idiopathic arthritis (JIA) is a chronic rheumatic disease. Patients suffer daily discomforts such as pain, fatigue, stiffness, and mood disturbances. Their exercise capacity is decreased to a variable degree and physical activity levels may be impaired. To prevent long-term cardiovascular risks associated with JIA and medication, it is important to encourage physical activity. To achieve this we developed Rheumates@Work (R@W), a combined internet-based and in person instruction model, an interactive, educational, and cognitive behavioral program. The aim of this study is twofold: to describe the theoretical background and design of R@W based on Pender's Health Promotion Model, and to assess its acceptance. METHODS: We enrolled 8 to 13-year-old JIA patients, from 3 outpatients clinics in The Netherlands, in R@W. Inclusion criteria were a low disease activity (VAS physician <20 mm), comprehension of the Dutch language and absence of relevant co-morbidity. We assessed acceptance by measuring the participants' commitment to the program, the level of interaction on patient's initiative (f.e. mails send by the patient), technical aspects and satisfaction. Commitment was defined as the percentage of participants that completed the assignments and how much encouragement the participants needed for this. Satisfaction was measured with an anonymous questionnaire concerning f.e. time investment and perceived benefits. Costs were monitored. RESULTS: Of the 64 patients we enrolled, 23 boys and 41 girls, 93.8 % completed the program. Participant-initiated interaction was seen in 10.7 %, 24.7 % send a mail because of technical problems. Eighty-two percent of the participants and 99 % of the parents liked the program, and 85 % of the participants indicated that they had learnt something, or quite a lot. Development costs of the program were low. CONCLUSION: The HPM is suitable for a behavioral intervention program such as R@W. Acceptance and satisfaction of R@W were high and the costs of the program were low. TRIAL NUMBER: ISRCTN92733069.

Assessment of disease activity by patients with juvenile idiopathic arthritis and the parents compared to the assessment by pediatric rheumatologists.

BACKGROUND: Self assessment of arthritis is important for recognition of disease activity and early initiation of therapy. Proper interpretation of physical symptoms is necessary for this. The purpose was to investigate the assessment by patients and parents of disease activity in juvenile idiopathic arthritis (JIA) and to compare their assessments to rheumatologists' assessments. METHODS: Patients and parents assessed 69 joints on a paper homunculus and marked each joint with a different color according to presumed presence of disease: active disease (AD), doubt, and non-active disease (NAD). Their assessments were compared to the rheumatologists' assessments. If patients and/or parents marked an inflamed joint, it counted as AD. Pain, functional impairment, and disease duration were analyzed to differentiate more precise between true and false positive and true and false negative assessments. RESULTS: We collected assessments of 113 patients and/or parents. AD was assessed 54 times, 33 of which were true positives. NAD was assessed 23 times, 22 of which were true negatives. Doubt was expressed 36 times, 9 of which were assessed by the rheumatologist as AD. Sensitivity and specificity of AD was 0.77 and 0.31. Pain and functional impairment scored highest in AD, intermediate in doubt, and lowest in NAD. CONCLUSION: Patients and/or parents seldom missed arthritis but frequently overestimated disease activity. Pain, functional impairment, disease duration, gender, and age did not differentiate between true and false positives for. Patients perceived JIA as active if they experienced pain and functional impairment. To reduce overestimation of the presence of AD we need to improve their understanding of disease activity by teaching them to distinguish between primary symptoms of JIA and symptoms like pain and functional impairment.

Promoting physical activity in children with juvenile idiopathic arthritis through an internet-based program: results of a pilot randomized controlled trial.

OBJECTIVE: Patients with juvenile idiopathic arthritis (JIA) are less physically active than healthy peers. Therefore, we developed an Internet-based intervention to improve physical activity (PA). The aim of this study was to examine the effectiveness of the program in improving PA. METHODS: PA was determined by activity-related energy expenditure, PA level, time spent on moderate to vigorous PA, and the number of days with > or =1 hour of moderate to vigorous activity, and was assessed with a 7-day activity diary. Aerobic exercise capacity was assessed by means of a Bruce treadmill test and was recorded as maximum endurance time. Disease activity was assessed by using the JIA core set. Adherence was electronically monitored. RESULTS: Of 59 patients, 33 eligible patients were included and randomized in an intervention (n = 17, mean +/- SD age 10.6 +/- 1.5 years) or control waiting-list group (n = 16, mean +/- SD age 10.8 +/- 1.4 years). All patients completed baseline and T1 testing. PA significantly improved in both groups. Maximum endurance time significantly improved in the intervention group but not in the control group. In a subgroup analysis for patients with low PA (intervention: n = 7, control: n = 5), PA improved in the intervention group but not in the control group. The intervention was safe, feasible, and showed a good adherence. CONCLUSION: An Internet-based program for children with JIA ages 8-12 years directed at promoting PA in daily life effectively improves PA in those patients with low PA levels. It is also able to improve endurance and it is safe, feasible, and has good adherence.

Physical activity in adolescents with juvenile idiopathic arthritis.

OBJECTIVE: To explore physical activity (PA) in adolescents with juvenile idiopathic arthritis (JIA) compared with a healthy population and to examine associations between PA and disease-related factors. METHODS: Total energy expenditure (TEE), activity-related energy expenditure (AEE), PA level, and PA pattern were assessed with a 3-day activity diary. Aerobic capacity was assessed using a Symptom Limited Bicycle Ergometry test. Functional ability was assessed with the Childhood Health Assessment Questionnaire. Disease activity was assessed using Paediatric Rheumatology International Trials Organisation core set criteria. Overall well-being was measured using a visual analog scale, and time since diagnosis was assessed by retrospective study from patients' charts. We used a cross-sectional study design. Reference data were collected from healthy Dutch secondary school children. RESULTS: Thirty patients and 106 controls were included (mean+/-SD age 17.0+/-0.6 and 16.7+/-0.9 years, respectively). TEE, AEE, and PA level were significantly lower in the JIA group. The JIA group spent more time in bed and less time on moderate to vigorous PA. Only 23% of the JIA patients met public health recommendations to perform >or=1 hour daily moderate to vigorous PA compared with 66% in the reference group. Higher PA was associated with higher levels of well-being and maximal oxygen consumption. CONCLUSION: Adolescents with JIA have low PA levels and are at risk of losing the benefits of PA. Low PA is not related to disease activity, and control over the disease does not restore previous PA levels. Interventions by pediatric rheumatologists are needed to increase PA levels in patients with JIA.

Aerobic and anaerobic exercise capacity in adolescents with juvenile idiopathic arthritis.

OBJECTIVE: To examine the aerobic and anaerobic exercise capacity in adolescents with juvenile idiopathic arthritis (JIA) compared with age- and sex-matched healthy individuals, and to assess associations between disease-related variables and aerobic and anaerobic exercise capacity. METHODS: Of 25 patients enrolled in a JIA transition outpatient clinic, 22 patients with JIA were included in this study (mean +/- SD age 17.1 +/- 0.7 years, range 16-18 years). Aerobic capacity was examined using a Symptom Limited Bicycle Ergometry test. Anaerobic capacity was assessed with the Wingate Anaerobic Test. Functional ability was assessed with the Childhood Health Assessment Questionnaire. Pain and overall well-being were measured using a visual analog scale. Disease duration and disease activity were also assessed. RESULTS: Absolute and relative maximal oxygen consumption in the JIA group were significantly impaired (85% and 83% for boys, respectively; 81% and 78% for girls, respectively) compared with healthy controls. Mean power was also significantly impaired (88% for boys and 74% for girls), whereas peak power was significantly impaired for girls and just failed significance for boys (67% for girls and 92% for boys). A post hoc analysis correcting for underweight and overweight demonstrated that body composition did not influence the results substantially. CONCLUSION: This study demonstrated that adolescents with JIA have an impaired aerobic and anaerobic exercise capacity compared with healthy age- and sex-matched peers. The likely cause for this significant impairment is multifactorial and needs to be revealed to improve treatment strategies.