Background: The respiratory movement measuring instrument (RMMI) is a method for examining the differences in anteroposterior diameter of the body during breathing.
Objectives: The aim of this study was to investigate the known group validity of the RMMI by comparing different body positions and breathing behaviours in healthy persons.
Method: The respiratory motion of the rib cage and the abdomen was measured by the RMMI in 40 healthy subjects. The measurements were undertaken in the supine and sitting positions and during normal, abdominal and thoracic breathing.
Results: The proportion of rib cage motion was 36% in the supine and 52% in the sitting position (P<0·001). The proportion of rib cage motion in the supine position was 21% during abdominal breathing and 57% during thoracic breathing, both significantly different (P<0·001) in comparison to normal breathing.
Conclusion: The RMMI showed a high degree of validity concerning distribution of motion between the rib cage and abdomen.
© 2010 The Authors. Clinical Physiology and Functional Imaging © 2010 Scandinavian Society of Clinical Physiology and Nuclear Medicine.