Table 1 Participant characteristics

n

15

15

15

Sex (n; Male/Female)

2/13

2/13

2/13

Age (years) mean ± SD

13.5 ± 2.2

13.6 ± 2.8

13.7 ± 2.7

Tanner stage (n; I–II / III–IV)

4/11

4/11

4/11

Body mass (kg) mean ± SD

49.3 ± 16.3

46.0 ± 13.5

48.9 ± 13.5

Height (cm) mean ± SD

155.8 ± 15.5

155.5 ± 14.6

154.9 ± 13.2

BMI (kg/m²) mean ± SD

19.6 ± 4.1

18.6 ± 3.0

20.0 ± 3.4

JIA subtype (n)

–

 oJIA

3

7

–

 pJIA RF−

7

4

–

 pJIA RF+

2

1

–

 ERA

2

1

–

 Psoriatic

1

1

–

 Undifferentiated

0

1

–

Disease duration (months) mean ± SD

48.1 ± 31.6

46.7 ± 34.1

–

Disease activity ^a (n)

–

 Active

4 ^b

4 ^c

–

 Inactive

11

11

–

DMARDs (n)

–

 NSAIDs

1

4

–

 MTX

8

8

–

 TNF-α blockade

15

0

–

 Adalimumab

3

0

–

 Etanercept

10

0

–

 Infliximab

2

0

–

 Low level of activity

8

6

5

 Moderate level of activity

3

5

7

 High level of activity

4

4

3

VO_2peak (ml/min) mean ± SD

1568.8 ± 670.9

1464.9 ± 445.3

1637.3 ± 579.9

VO_2peak/body mass (ml/kg/min) mean ± SD

33.0 ± 9.9

32.6 ± 6.0

33.7 ± 8.0

Rest metabolism (kcal/day) mean ± SD

1467.2 ± 427.6

1431.7 ± 423.7

1767.6 ± 622.4