Oral Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Introduction: Although physical activity is often perceived by patients as a trigger of low back pain (LBP), and occupational health studies suggest deleterious effects of some activities, observational studies and randomized trials indicate beneficial effects of activity on LBP. This may be because the short- and long-term effects of activity differ, and activity-LBP relationships might differ based on activity type. To distinguish the short- vs. long-term effects of specific physical activities, we conducted a longitudinal case-crossover study nested within a cohort study. The first aim was to estimate the “short-term” effects (within 24 hours) of specific activities on episodes of new or worsened LBP (“flares”). The second aim was to estimate the “long-term” effects of specific activities on LBP-related functional limitations at 1-year follow-up as measured by the Roland-Morris Disability Questionnaire (RMDQ).

Methods: Participants were individuals (18-65 years old) seeking care for LBP in primary care in the Veterans Affairs system. Participants completed up to 36 scheduled surveys and additional patient-initiated surveys (triggered by the onset of new flares) over 1-year follow-up. Surveys inquired about current flares and activity exposures over the 24 hours before survey completion (if no flare was reported), or over the 24 hours before flare onset (if a flare was reported). Activity exposures included climbing, twisting, squatting, bending, crawling, pushing/pulling, lifting, sitting, standing, and walking. The first aim used conditional logistic regression to estimate associations between a greater number of hours spent in each activity and subsequent LBP flares, using adjusted odds ratios (ORs) and 95% confidence intervals (CIs), with time period as the unit of analysis. For the second aim we used linear regression to estimate person-level associations between activity exposures at baseline and RMDQ scores at 1-year follow-up. Analyses accounted for multiple statistical comparisons and multiple potential confounders. Although this abstract uses the term “effect” for simplicity, all associations are derived from observational data.

Results: The study sample (n=416) included 25% women and mean participant age was 48 years. There were statistically significant short-term detrimental effects on LBP flares for a greater number of hours in the past 24 hours spent doing the following activities: twisting (OR=1.06 per hour [95% CI 1.03-1.08]); squatting (OR=1.05 [95% CI 1.02-1.08]); bending (OR=1.06 [95% CI 1.03-1.08]); pushing/pulling (OR=1.06 [95% CI 1.03-1.09]); and lifting >10 pounds (OR=1.05 [95% CI 1.03-1.07]) (Figure 1). Greater hours spent sitting were significantly protective of flares in the short term (OR=0.96 [95% CI 0.94-0.98]). Standing and walking were not significantly associated with flares. In a preliminary complete-case analysis, no significant associations were found between any baseline activity and long-term functional limitations at 1-year follow-up.

Discussion: Although greater hours spent in some activities were associated with short-term detrimental (squatting, bending, pushing/pulling, lifting) or protective effects (sitting) on LBP flares, no activity performed at baseline was significantly associated with long-term functional limitations at 1-year follow-up. These findings suggest that while some activities are associated with LBP flares in the short term, engaging in these activities may not have meaningful effects on long-term functional outcomes.