The association between trunk flexion and low back pain in blue-collar workers: A systematic review.
Antoine Maillard, Timon Pasche, Pieter Coenen and 1 others
Across four studies of blue-collar workers, objectively measured trunk flexion at work was not associated with increased low back pain.
One study even found a small protective signal. The evidence is limited, from Northern and Western Europe only.
Key findings
1Across four studies, time spent in trunk flexion ≥30° was not associated with increased risk of low back pain.
2For higher exposure (≥60° and ≥90°), the four studies found no significant association between duration of trunk flexion and low back pain.
3One study found an inverse association for ≥30° trunk flexion (HR 0.87, 95% CI 0.78–0.97, p = 0.01), suggesting a possible protective effect of a small exposure to trunk flexion.
Still to come
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
Only four studies were found, all from Northern and Western Europe, so the findings may not apply to workers in other regions where exposure levels differ. The median duration of trunk flexion ≥60° was about 7 minutes per day in one study, so the results may not apply to workers who spend much more time in deep flexion. One of the four studies included white-collar workers alongside blue-collar workers, which the authors flagged as increasing risk of bias for this population. The studies measured trunk flexion, not lumbar flexion specifically, so the findings may not capture the spinal segment most relevant to low back pain. The healthy-worker effect may mean the most severely affected workers were excluded from the studies, as companies often reassign them to less demanding tasks. Heterogeneity in designs and measures prevented a meta-analysis, so the findings are a narrative synthesis of four small studies.
Declared interests
The authors received no financial support and declared no conflicts of interest.
The easy way to misread this
Do not read the one significant inverse association (HR 0.87) as proof that bending protects the back. It came from a single study, the other three found no association at that level, and the overall evidence is limited to four studies in Northern and Western Europe.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →