Development and Evaluation of the Index of Muscle Function

Abstract

Evaluation of functional capacity is important when defining needs for therapy as also is the evaluation of rehabilitation effects in patients with rheumatic diseases. The aim of this overview is to describe the development and initial evaluation of the Index of Muscle Function (IMF), a battery of functional performance tests focusing mainly on the muscle function of the lower extremities. In addition, new data concerning reliability and validity are presented. The IMF total index can be divided into four separate areas: pre-tests of general functioning, muscle strength, muscular endurance and balance/coordination. Results indicate that the IMF is simple to use both at the clinic and at the patient's home, that it possesses sufficient properties with respect to reliability and validity, that it discriminates between different groups, and that it detects changes within rehabilitation in patients with rheumatoid arthritis.