Table 1 Terminology pertaining to the effects of activity during LBP
Term | Definition |
|---|---|
Flare | An increase in pain (such as LBP), typically lasting hours to days [7]. Flares may occur either in the setting of existing pain, or in the setting of minimal LBP or no LBP [6] |
Episode | A specific instance of a flare, in which LBP is preceded by a period of minimal or no LBP |
Recurrence | A new episode of LBP, preceded by a period of minimal or no LBP, preceded by a past history of LBP [6, 35, 36] |
Trigger | An exposure with a transient effect. Triggers may often have transient durations [33] Example: Lifting may ‘trigger’ the abrupt onset of a flare of LBP |
Transient effect (short-term effect) | An effect on an outcome that occurs within a short period of time (e.g., ≤ 24 h) after an exposure, such as estimated in a case-crossover study [33] Example: Lifting a heavy weight might cause an immediate flare of LBP |
Long-term effect | An effect on an outcome that occurs over longer periods of time (e.g. days to weeks) |
Cumulative effect (overall effect)* | An overall effect within which both transient effects and long-term effects are subsumed. Cumulative effects are estimated by cohort studies and RCTs [37] Example: Lifting heavy weights often may increase functional limitations at 12-month follow-up |
Effect period | The duration within which the transient effect of an exposure can be expected to manifest, in a target population [33]. The effect period of activities on LBP is thought to be < 24 h [7, 38] |