Short-term physical risk factors for new episodes of low back pain.
Prospective evidence from the South Manchester Back Pain Study. 

Croft PR; Papageorgiou AC; Thomas E; Macfarlane GJ; Silman AJ 
University of Keele, School of Postgraduate Medicine, Industrial and
Community Health Research Centre, Stoke-on-Trent, United Kingdom. 

Spine, 1999 Aug, 24:15, 1556-61 
STUDY DESIGN: A prospective population-based cohort study performed
in South Manchester, United Kingdom. OBJECTIVES: To determine
whether nonoccupational physical activity and indicators of physical
stress on the spine predict low back pain in the short term. 

SUMMARY OF BACKGROUND DATA: There is evidence that physical activity outside the workplace helps to protect against low back pain in the long term.
However, such activity may injure or stress the spine in the short term.
METHODS: A baseline survey questionnaire identified 2715 adults, aged
18-75 years, with no low back pain at the time of the survey. Information
on potential predictors of low back pain also was obtained. New episodes of back pain were identified during the subsequent year. RESULTS: A new low back pain episode occurred in 34% of men and 37% of women. Poor general health at baseline was the strongest predictor of a new episode of pain (men: relative risk (RR) 1.5, 95% confidence intervals (CI) 0.8, 2.7; women: RR 2.2, 95% CI 1.2, 4.0). High weight was associated with subsequent low back pain in women (RR 1.4; 95% CI 1.0, 2.0), but neither height nor weight predicted low back pain in men. A self-rated low level of physical activity was not consistently linked with subsequent low back pain, nor were specific nonoccupational physical activities, apart from home-improvement work in men and regular sports in women.

CONCLUSION: Although some specific activities may be hazardous to
the back, physical activity outside the workplace does not increase the
short-term risk of low back pain overall. Leisure-time physical activity is
not a hazard to the back, whereas poor physical health in both genders
and heavier weight in women do increase the risk of new low back pain
episodes in the short term.