Introduction: Both the floor-to-waist lifting task of the Isernhagen Work Systems Functional Capacity Evaluation (IWS FCE) and recommended weight limit (RWL) of the NIOSH produce safe lifting weights and are used world-wide nowadays. It is unknown whether they produce similar safe lifting weights. Aim of this study was to compare FCE performance on the floor-to-waist lifting task and RWL of the NIOSH lifting guideline for this task, in patients with chronic low back pain (CLBP).
Methods: Ninety-two patients performed the FCE lifting task. RWL was calculated for this task. Performance was compared with RWL. A lifting index was calculated by dividing performance by RWL. Differences between groups with a lifting index < or =1, 1-3, and >3 were calculated for pain intensity, scores on the Roland Morris Disability Questionnaire (RMDQ) and work status.
Results: Men lifted on average 32.5 kg (SD 15.4) and women 18.8 kg (SD 7.8). RWL for this task was 12.8 kg. Mean difference between performance and RWL was 15.0 kg (SD 14.7; range -8.8 to 59.2). The Roland Morris Disability score of patients with a lifting index < or =1 was significantly lower than patients with a lifting index 1-3 and >3. No difference in pain intensity and work status was found between groups.
Conclusion: It was concluded that performance on the FCE floor-to-waist lifting task and RWL of the NIOSH for this task produce different safe lifting weights in individual patients with CLBP, which may result in contradictory recommendations about need for rehabilitation and return to work.