Single leg landing kinematics in volleyball athletes: A comparison between athletes with and without active extension low back pain.

The purpose of this study was to compare kinematics of the lower extremity and lumbar spine during a single leg landing task between female volleyball athletes with and without persistent low back pain (LBP). In this cross sectional study, 36 volunteer female volleyball athletes with (n = 18) and without (n = 18) LBP were recruited. Two specifically trained physical therapists selected only athletes with a specific movement-based subgroup of LBP for inclusion. Three dimensional kinematic and ground reaction force data were recorded for each athlete across three single leg landing trials by utilizing a Vicon 6-camera motion capture system and one in-floor embedded Kistler force plate, respectively. Independent t-tests compared data between the two groups. Lumbar lordosis when standing (p = 0.046) as well as on initial contact (p = 0.025) and at the time which the maximal vertical ground reaction force occurred (p = 0.020) were significantly greater in the LBP group. There were no other