Test day. Subjects met at either 8.30 a.m. (Ex) or 9.30 a.m. (NEx) according to randomization. Following exercise or none, blood and urine samples were taken (T1) and regional anaesthesia was applied. Two catheters were hereafter positioned in the suprapatellar recess and in the sub synovial tissue on the medial side of the knee, respectively. Catheters were removed after three hours of microdialysis. The removal was preceded by blood and urine samples (T2). Samples of dialysate were collected every 30 minutes. Relative recovery was calculated for every sample and samples were later pooled (t1 = Sample 1 to 3; t2 = Sample 4 to 6).