Fig. 2

Line and scatter plot showing the median (interquartile range) pain intensity (VAS 0–100 mm) during microdialysis in the vastus lateralis muscle of the most painful leg in 24 patients with fibromyalgia (FMS) and 27 healthy controls (CON) before (a) and after (b) 15 weeks of resistance exercise twice per week. Microdialysis was performed for 220 min. During the first 140 min the participant rested (data not shown), whereafter they performed dynamic contractions (EXC) of the leg (knee extension) for 20 min followed by another 60 min of rest (RECOVERY). In FMS, but not in CON, pain intensity increased during the dynamic contractions at both sessions (Friedman test: P < 0.001). ^# P < 0.001 compared to 140 min (Dunn’s post-hoc test). VAS visual analogue scale