Table 2 Search strategy on MEDLINE (OVID interface)

1. Experimental pain

((Experiment* adj5 pain) or (experimentally-induced adj4 pain) or (pain-induced or “experimental induced” or “experimentally induced”) or (induced adj3 pain) or “induced LBP” or (noxious adj3 stimul*) or (nociceptive adj3 stimul*) or (pain* adj3 stimul*)).mp

2. Pain model

(((“hypertonic saline” or capsaicin or glutamate or “laser evoked potential” or “laser evoked potentials” or “nerve growth factor”) and pain) or (electric* adj2 pain*) or (electric* adj2 stimul*) or (mechanic* adj2 pain*) or (mechanic* adj2 stimul*) or (thermal* adj2 pain*) or (thermal* adj2 stimul*) or (chemical* adj2 pain*) or (chemical* adj2 stimul*) or (cutaneous adj2 pain*) or (cutaneous adj2 stimul*)).mp or Saline Solution, Hypertonic/ or Electric Stimulation/

3. Body region stimulated

Back Pain/ or (“back pain” or “back ache” or backache*).mp or exp Low Back Pain/ or (“low back pain” or “lower back pain” or lumbago or LBP or “lumbar pain” or “lumbar spine” or “low back” or “lower back”).mp

4.

1 OR 2

5.

3 AND 4