Juvenile idiopathic arthritis (JIA) comprises a group of chronic inflammatory conditions in children that affect the joints, causing swelling, stiffness, and pain. Physical exercise is normally recommended for children affected by the disorder to maximize their chances of maintaining joint mobility and function, as well as muscle tone.
Although some studies have analyzed the effects of aerobic physical exercise in children with JIA, studies assessing the impact of resistance exercises are still lacking.
“Since resistance exercise has been shown to be well-tolerated and to have beneficial effects [in children with other disorders, including cystic fibrosis and cerebral palsy], we sought to test the effects of resistance exercise in a cohort of children with polyarticular JIA,” the investigators said.
The researchers, from the University of Alabama, and the Children’s National Health System in Washington, D.C., set out to examine the safety, tolerability, viability, and clinical effects of slow speed resistance exercise in a group of children with polyarticular JIA. This subtype, in which at least 5 joints are involved, affects 30–50% of children with JIA.
A total 33 children with polyarticular JIA were randomly assigned to two different groups: a control group, in which they performed a series of aerobic exercises at home, three times a week, for a period of 12 weeks; or an intervention group, in which they performed slow speed resistance exercise, with the help of a certified instructor, once or twice per week, for a period of 12 weeks.
Clinical parameters, including body composition, aerobic fitness (measured by maximum oxygen consumption), muscle strength, and the children’s quality of life were assessed in all study participants before and after completing both exercise programs.
Adherence to the exercise plan was low among children from both groups. From the 17 children initially assigned to the intervention group, only nine (53%) reported carrying out any form of exercise routine. From these, only five (55%) completed the 12 weeks of training.
Likewise, among the 16 who had been assigned to the control group, only eight (50%) performed aerobic exercise training at home at least once per week, and only two (12%) reported doing so more than once per week.
No statistically significant differences were found in any clinical parameters before and after the completion of the exercise plan among children from both groups.
Researchers found that body fat remained relatively high in children from both groups, with only 17% of the children in the intervention group and 23% of those in the control group remaining within a normal range of below 30% in total body fat.
“Children with JIA participated safely in this resistance exercise protocol. The exercise was well-tolerated with no serious adverse events noted,” the researchers said.
“While individual subjects reported improvement in fatigue and improved energy, there was no statistical difference in pre- and post-exercise measures of body composition or quality of life. Identifying ways to improve adherence and encourage exercise in children with JIA is important,” they added.