Exercise tests as outcome measures

Outcome assessments of physical fitness attributes such as endurance, strength, and flexibility are not measured routinely in clinical trials or clinical practice in either adults or children with rheumatic diseases. Although physical fitness is not a measure of disease severity, it can be a critical indicator of capacity to function. Adequate fitness is necessary for the performance of positive health behaviors that enhance health status and wellness in spite of chronic disease. The purpose of this paper is to explore the conceptual, methodologic, and analytic issues related to the use of exercise tests as outcome measurements of physical functioning in persons with rheumatic disease.