Alnojeidi AH, et al. - The association between low back pain (LBP) and muscle-strengthening activity (MSA) was investigated among U.S. adults using gender-stratified analyses. The physicians demonstrated that in MSA, engaging at least 2 days/wk was correlated with lower odds of LBP. Moreover, smoking could be an important mediating factor that needed to be considered in future LBP research.

• A total of 12,721 participants from the 1999 to 2004 National Health and Nutrition Examination Survey (NHANES) were included.
• The physicians categorized participants into 1 of 3 levels of self-reported MSA: no MSA, insufficient MSA (1 day/wk), or meeting the 2008 Department of Health and Human Services (DHHS) recommendation for MSA (≥2 days/wk).

• The physicians demonstrated significantly lower odds of reporting LBP among women [odds ratio (OR) 0.82, 95% confidence interval (CI) 0.70-0.96, P = 0.03] and men (OR 0.86; 95% CI 0.70-0.96, P = 0.01) who reported amounts of MSA that met the DHHS recommendation then those reporting no MSA in gender-stratified analyses.
• Among women (P = 0.03), the odds remained significant but not among men (P = 0.21) following adjustment for smoking status.