Impaired cardiorespiratory and neuromuscular fitness in children and adolescents with juvenile idiopathic arthritis: a cross-sectional case–control study in the era of biologic drug therapies

Table 2 Physical fitness in patients with JIA and in healthy controls (mean ± SD)

	JIA		Controls		Oligoarticular JIA		Polyarticular JIA
	n = 73		n = 73		n = 18		n = 55
Ergospirometry^a		n		n		n		n
W_max, Watts	119 ± 39.8	69	139 ± 50.9	72	113 ± 39.2	17	122 ± 40.2	52
W_max/kg, Watts/kg	2.80 ± 0.54**	69	3.14 ± 0.50	72	2.80 ± 0.52	17	2.80 ± 0.55	52
VO2_peak, l/min	1.66 ± 0.57**	66	2.18 ± 0.58	53	1.50 ± 0.55	16	1.71 ± 0.57	50
VO2_peak/kg, ml/min/kg	38.7 ± 7.53**	66	45.8 ± 6.59	53	36.4 ± 6.92	16	39.4 ± 7.64	50
Neuromuscular^b tests
Shuttle run, s	24.4 ± 3.58**	72	21.6 ± 1.93	68	24.5 ± 2.07	18	24.4 ± 3.97	54
Sit-ups, number/30 s	14.6 ± 5.55**	72	18.1 ± 5.61	70	12.5 ± 5.68	18	15.3 ± 5.39	54
Handgrip strength, kPa
Right	66.3 ± 24.8	73	75.3 ± 28.0		66.7 ± 6.4 62.3		66.2 ± 24.5
Left	64.3 ± 24.7*		74.1 ± 8.60	73	± 2.46	18	64.9 ± 25.6	55
Standing long jump, m	1.42 ± 9.52**	71	1.60 ± 3.90	68	1.40 ± 25.5	17	1.43 ± 30.9	54
Box and block, number/min
Right	65.3 ± 11.9	71	65.1 ± 11.00		63.7 ± 9.45		65.9 ± 12.6
Left	63.8 ± 11.2		63.6 ± 11.2	73	61.3 ± 8.28	18	64.6 ± 12.0	53
Balance test, support/30 s	2.01 ± 1.97	69	1.85 ± 1.73	52	2.22 ± 1.93	18	1.94 ± 2.00	51
Physical activity min/day
Active time	89.0 ± 44.7*	62	112.7 ± 62.1	72	81.9 ± 46.4	16	91.5 ± 44.3	46
Sedentary time	427 ± 213*	65	343 ± 211	70	408 ± 173	16	432 ± 225	49

W_max maximal workload, VO2_peak peak oxygen uptake
^* p < 0.05, **p < 0.01 vs. controls
^aFour patients could not keep the cadence stable because of not knowing how to cycle or did not find motivation for cycling. The missing respiratory gas measurements were due to unwillingness to use the mask
^b Due to lack of motivation, all tests were not completed by every patient

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