McPhee ME, et al. - Pronociceptive and antinociceptive mechanisms were investigated in recurrent low back pain (LBP) patients across painful and pain-free periods, compared with age/gender-matched asymptomatic controls. Researchers assessed 30 recurrent LBP (RLBP) patients during a painful episode (day 0) and when pain-free (day 28) and compared them with 30 controls, over the same timeframe. Reduced pressure pain thresholds at the arm and back were reported in recurrent LBP patients on day 0 compared with day 28 and with controls on day 0. RLBP patients exhibited reduced cuff pain detection threshold and increased ratings of suprathreshold test stimuli on day 0 compared with day 28. On day 0, RLBP participants also showed enhanced temporal summation of pain magnitude (increase in visual analogue scale scores) compared with day 28 and with controls on day 0. Relative to controls, RLBP participants had overall lower conditioned pain modulation magnitude (increased threshold during conditioning). RLBP patients exhibit enhanced pronociceptive mechanisms. Measures returned to similar levels as controls when pain-free, except for conditioned pain modulation, which remained impaired.