*In favour of.
+, limited evidence found; ++, moderate evidence found; +++, strong evidence found; ±, conflicting evidence for effectiveness; CWH, clinic-based work hardening; FU, follow-up; NE, no evidence found for effectiveness of the treatment: RCT(s) available, but no differences between the intervention and control groups were found; SR, systematic review; RCT, randomized clinical trial; WWH, workplace-based work hardening.