Fitness and Training in Children With Juvenile Idiopathic Arthritis

Abstract and Introduction

Abstract

Physical activity and fitness are increasingly recognized as important outcomes in the follow-up and treatment of patients with juvenile idiopathic arthritis. In the past, major concerns were on the detrimental effects of physical exercise; now evidence is growing on the beneficial effects of exercise. The purpose of these exercise programs is to promote a more active lifestyle and/or enhance physical fitness. This article will review the findings of recent studies in juvenile idiopathic arthritis in the area of physical fitness, physical activity and training. It is advised that clinicians are discussing appropriate levels of physical activity (daily participation in >60 min of moderate-to-vigorous physical activity) with their patients in clinical consultations.

Introduction

Nowadays, pediatric health professionals have acknowledged the use of exercise in the prevention, diagnosis and treatment of chronic childhood conditions and related health problems. Physical fitness is a principal element of clinical exercise physiology and is a multidimensional concept that has been defined as a set of attributes that people possess or achieve to perform physical activity.^[1] In current pediatric research, physical fitness has become synonymous with cardiorespiratory or aerobic fitness. In general, aerobic fitness is expressed as the maximal oxygen uptake (VO_2max); and is widely recognized as the best single measure of a person's aerobic fitness.^[2]

As opposed to healthy children, children with a chronic condition often are constrained from participation in physical activities or sports programs as a consequence of real or perceived limitations imposed by their condition. The condition itself often causes hypoactivity, which leads to a deconditioning effect, a reduction in the functional ability and to further hypoactivity.^[3] Physical activity can be measured using different methods. All methods have their pros and cons. For example, doubly-labeled water can be used to estimate the activity energy expenditure with great precision over a 2 week period; however, the costs are high and ease of measurement is low. On the other hand, activity estimates from questionnaires and activity recalls are relatively easy to obtain but the precision of these methods are low. Activity monitoring, using small devices worn at the hip, wrist or ankle that record acceleration of a body segment, seems to be a promising method to objectively assess and profile physical activity,^[4–6] and seems to be more valid than indirect assessments (e.g., questionnaires and activity logs).^[7]

Physical fitness can also be measured using different methods. For example there are several different exercise testing methods to directly measure peak oxygen uptake – the gold standard – of aerobic fitness, such as graded treadmill or cycle ergometer tests with respiratory gas analysis. In addition, there are also tests to estimate the aerobic fitness from, for example, endurance time (e.g., Bruce treadmill test^[8]) or time to complete a task (e.g., 9-min run/walk^[9]). For these tests there is also a trade-off between ease of measurement and precision. Direct measurement of oxygen uptake during peak exercise is more precise than estimates of aerobic fitness from field tests.

Sufficient levels of physical activity and physical fitness are just as important for the health status of children with juvenile idiopathic arthritis (JIA) as it is for healthy children.

Physical fitness is not only an important indicator for health, it is also an important determinant of functional capacity of a subject. Unfit and/or inactive children are at additional risk for a variety of health conditions associated with a hypoactive lifestyle (e.g., cardiovascular conditions, obesity and prediabetes). Furthermore, sufficient levels of physical activity is necessary for an optimal physical, psychological and emotional development of a child.

However, children with JIA might have a reduced physical fitness^[10] and be less active than peers,^[11–13] which causes an unnecessary risk for the development of cardiovascular disease as well as a risk for reduced psychosocial and physical functioning. The link between physical activity, health-related fitness and health is described by Bouchard and coworkers in the model shown in Figure 1.^[14]

(Enlarge Image)

Figure 1.

The model by Bouchard and coworkers linking physical activity, health-related fitness and health.
Reproduced with permission from [14].

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