Physical Fitness, Activity and Training in Children with Juvenile Idiopathic Arthritis

Tim Takken

Disclosures

Pediatr Health. 2010;4(5):499-507. 

In This Article

Fitness Training

Aerobic Capacity

In a recent Cochrane review it was identified that only three published randomized-controlled studies investigated the effects of exercise training for children with JIA.[46] However, none of these studies found improvements in VO2peak following the aerobic training program. This lack of effect can be can be due to a low exercise frequency (e.g., once a week), low exercise intensity (intensity of exercise has to be above the intensity of daily activities), a low exercise adherence (children would often skip exercise sessions) or they did not perform the prescribed home exercises. These factors are essential for improving physical fitness.

However, aerobic fitness is important to improve the child's endurance for daily physical activities and play. In addition, aerobic fitness aids the recovery following intensive exercise. Based on the available literature, it is recommended that children with JIA and a deficit in aerobic fitness should train at least twice a week, with a moderate-to-vigorous intensity (60–85% HRpeak), for 45–60 min per session for at least 6–12 weeks.[12,13] The specific mode of exercise appears to be less important than the intensity, duration and frequency. However, weight-bearing exercise is necessary to maintain optimal bone growth and density. Low impact activities to improve proprioceptive function, balance and coordination can be incorporated into aerobic conditioning programs. Furthermore, large muscle groups should be used for improving VO2peak as the exercise mode of testing should be comparable with the training mode (e.g., a walking/jogging exercise program should be evaluated using treadmill testing and not using cycle ergometry testing).

For children with active disease it is advised to refrain from any formal exercise training when they have fever (i.e., rectal core temperature >38.3°C). In addition, when they have active joints in the lower extremities, it is advised to do only low-to-moderate intensity exercise without intensive loading of the joints (e.g., running or jumping).[47] For children with active disease in the wrist for example, it is recommended to wear a (dynamic) splint during exercise to protect the joint from high impact forces. Activities that cause pain and increase swelling in joints with active arthritis should be stopped or modified to lessen stress to the joint.[47]

Anaerobic Capacity

In a recent study van Brussel et al.,[29] hypothesized that training of the anaerobic energy system (e.g., high-intensity interval training) might be equally valuable as training of the aerobic system and, therefore, warranted in children with JIA. Although, this training modality has not yet been studied in children with JIA, improvements have been observed in function and fitness with anaerobic exercise training in children with other chronic conditions (e.g., cystic fibrosis and cerebral palsy).[48,49] Particularly in children with a larger reduction in anaerobic capacity compared with aerobic capacity, this training modality might be effective. In addition, children prefer this anaerobic type of exercise, compared with the adult type of continuous endurance exercise. Suggested exercise sets consist of several (five) 15-bouts of high-intensity (or all out) 15–30 s sprint interchanges with 1–2 min of active rest (cycling with low resistance). A training session could consist of three of these exercise sets, with 5 min of active rest for recovery between the three sets of interval training.

Muscle Strength

There is little evidence concerning the effectiveness of strength training for children with JIA. There is only one study, which is only published in an abstract form that studied muscle strength training in children with JIA. Fisher and colleagues examined the effects of resistance exercise using isokinetic equipment in 19 children with JIA of ages 6–14 years, who trained as a group three times a week for 8 weeks.[50] Each child's program was individualized and progressed based on their initial test results and response to training. Subjects demonstrated significant improvements in quadriceps and hamstring strength and endurance, contraction speed of the hamstrings, functional status, disability and performance of timed tasks. Control subjects with JIA who did not exercise had relatively no change to a slight decrease in muscle function during the same time period.[50]

To date, there are no other published reports investigating the effects of strength training in children with JIA. However, recommendations for healthy children can be followed for use in children with JIA. For improving muscle strength children should perform resistance exercises for 2–3 times per week at an intensity of 60–75% of their one repetition maximum. The latter will be approximately 13–15 repetitions of an exercise until fatigue. The time per session will be 30–45 min. It is advised to use the entire range of motion of a patient (or within pain limits). The program should increase in intensity from 60% of the one repetition maximum with 1–3 sets, to a higher intensity of 75% with 3–4 sets. It is recommended that the resistance is only increased when 15 or more repetitions can be made with a sufficient technique, and resistance will only be increased with 5 to 10% per 3 weeks. A warm-up period of light activity, such as cycling should precede strength testing.

Encouraging Active Healthy Living

Several studies have identified a hypoactive lifestyle of children with JIA.[16–18] A significant association has been reported between accelerometry-measured physical activity and health-related fitness (VO2peak) in children with JIA,[12] suggesting a cause–effect relationship. In addition, no adverse effects of regular sport activity have been observed on joint scores in children with JIA.[51] However, the most frequently participated sports activity in that study was cycling and swimming (nonweight-bearing activities).[51] On the other hand, a controlled weight-bearing exercise intervention study found improvements in joint status following 8 weeks of training in children with JIA.[9] Adult data indicate that exercise can have an anti-inflammatory effect in arthritis patients[52] as well as in other inflammatory diseases.[53]

The link between the physical activity levels of children and motor performance[54] suggests that the physical activity levels of children with JIA might be enhanced through the improvement of the reduced motor proficiency observed in children with JIA.[55] Furthermore, given the fact that adult physical activity levels are established in youth, it is important to encourage children and families of children with JIA to participate in regular physical activity. Regular physical activity can help in the prevention of cardiovascular risk factors, obesity, reduced bone health and reduced health-related quality of life in youths with JIA.

Recently Lelieveld et al. performed a randomized-controlled study to investigate an internet-based activity promotion program among 33 JIA patient (10.8 ± 1.5 years old).[8] This 17-week web-based e-learning program was combined with four group sessions. The following strategies were used to promote physical activity: health education; explanation of benefits of physical activity; reinforcement of self-efficacy; influence of family and school is recognized and used to promote physical activity; physical activity options in daily life are explored and encouraged; and smart goals are set (e.g., 'I am going to cycle to school three times a week instead of going by car, for the coming 2 months'). They observed the following changes in physical activity: energy expenditure from physcical activity was improved by +1.24 MJ/day, the amount of moderate-to-vigorous physical activity improved with 1 h per day and the number of days with more than 1 h of moderate-to-vigorous physical activity increased with 1.2 day per week. They observed the largest effects in children with low physical activity levels at baseline.

Although exercise capacity, as measured using the endurance time on the Bruce treadmill test, improved significantly this improvement was only 26 s, which could be hardly recognized as clinically relevant (effect size of 0.33). This is not surprising, since the relationship between physical activity and physical fitness is low in JIA[12] as well as in other childhood conditions, such as congenital heart disease.[56] It might be more effective to combine formal exercise training with a physical activity promotion program to increase activity as well as physical fitness in children with JIA.

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