Illustrative relative blood flow (rBF), oxygen extraction fraction (rOEF) and oxygen consumption rate (rVO
) throughout fatiguing exercise in (a) a subject with firbromyalgia (FM) and (b) a healthy control, all presented in percentage relative to baseline (%). The first two vertical lines indicate the beginning and the end of fatiguing exercise respectively, and the last four vertical lines indicate the time points 3, 6, 9 and 12 minutes after exercise. The arrow indicates the time points immediately post-exercise (over 6 seconds). Note that the muscle motion artifacts during exercise and during maximal voluntary isometric contraction (MVIC) tests at time points 3, 6, 9 and 12 minute post-exercise may contaminate optical measurements, as seen from the peaks in the figure.