Despite the opinions of clinical experts that patients who might benefit from traction may represent distinct sub-groups of patients, most studies have not attempted to narrow their inclusion criteria beyond loose definitions of 'acute' or 'chronic' symptoms. While these studies seem to indicate that traction interventions will be of little benefit when administered to large groups of patients without a prior attempt to select which patients are most likely to benefit, they are not sufficient to preclude the possibility that a subgroup of patients may benefit substantially from the intervention. Recent preliminary studies suggest a there exists a subgroup of patients with LBP that is likely to benefit from traction.