In order to look for relationships between leisure sports activity and both low back trouble and back flexibility, 958 people, aged 10-84 years, were examined. Their history of low back trouble and leisure sports participation was recorded, together with measurements of maximal lumbar sagittal mobility. No evidence was found to suggest that the extent of sports participation either during childhood or as an adult was related to the development, frequency, or onset-age of low back trouble. Although sports participation was not associated with flexibility in schoolchildren, adults who had continued leisure sports for >5 years showed relatively reduced lumbar mobility. On the basis of the results presented here, it is concluded that sporting pursuits at amateur/leisure level do not, in themselves, represent a major risk factor for low back trouble. On the contrary, it was found that adults typically continued leisure sports participation for some years after developing low back trouble. Sports participation, in general terms, is not contraindicated for those who have experienced low back trouble, but regular exercise does not apparently result in increased lumbar flexibility.