The contribution of reduced physical activity of a defined duration to the risk of fall-related fractures and serious soft tissue injuries is not known. We conducted a prospective population-based study among the home-dwelling elderly to examine the association between a recent decline in physical activity and the occurrence of fall-related fractures and soft tissue injuries. The study population consisted of representative sample of home-dwelling older adults who conducted heavy outdoor work activity at least once a week at baseline (n = 284; 136 men, 148 women) and among whom in 93 persons (33%) heavy outdoor work activity was found to have declined during the 2 1/2 years follow-up. Fall-related fractures (n = 24) and serious soft tissue injuries (n = 49) were recorded from the time of the follow-up examination until the end of a further follow-up period lasting 3 1/2 years on average. A decline in heavy outdoor work activity did not predict the occurrence of soft tissue injuries (Mantel-Cox 0.795, p = 0.373), but a greater proportion of those with a decline (n = 14, 15%) than of others (n = 10, 5%) suffered fractures (Mantel-Cox 10.231, p = 0.001). Other risk factors for fractures were female sex (p = 0.03), slow choice reaction time (p = 0.02) and dependency as regards at least one basic activity of daily living (p = 0.01). According to the Cox proportional hazard model, the adjusted hazard ratio of fracture as regards a decline in heavy outdoor work activity was 2.7 (95% CI 1.14-6.62). A recent decline in heavy outdoor work activity predicts the occurrence of fractures, but not the occurrence of serious soft tissue injuries. Early recognition of a decline in physical activity may help in prevention of fractures among the elderly.