Are flexibility and muscle-strengthening activities associated with a higher risk of developing low back pain?

ObjectivesTo examine the association between participation in flexibility or muscle-strengthening activities with the development of low back pain.DesignObservational cohort study.MethodsThe cohort included 4610 adults, 17% female, between 20 and 81 years of age (mean 46.6, standard deviation 4.96). The cohort was followed for a mean of 4.9 years for self-reported low back pain. All participants reported at baseline whether they performed flexibility or muscle-strengthening activities, including specific sub-types.ResultsNeither general performance of flexibility or muscle-strengthening activities were associated with a higher incidence of low back pain compared to those who did not perform these activities. Those who reported stretching, as a specific flexibility activity were at a higher risk of developing low back pain compared with those who performed no flexibility exercises, reported callisthenic flexibility activities, or attended exercise classes. Those who reported using weight training machines, as part of muscle-strengthening activities, had a higher risk of reporting low back pain, compared with those who did not perform muscle-strengthening activities or performed callisthenic or free weight activities.ConclusionsIn this sample, stretching or use of weight training machines is associated with increased risk of developing low back pain compared to use of free weights, callisthenics or exercise classes.