Lumbar spine and hip motion angles are associated with movement direction of pain in patients with low back pain

BACKGROUND: The evaluation and treatment of patients with low back pain (LBP) often involve categorization based on movement direction. However, it is not certain whether the lumbar spine and hip motion angles are associated with movement direction in individuals with LBP. OBJECTIVE: The purpose of this study was to verify whether the motion angles of the lumbar spine and hip joint are associated with the movement direction in individuals with LBP. METHODS: Participants were recruited as volunteers at the authors' institutions. In this cross-sectional observational study, participants were divided into two groups: those without LBP and those with LBP. To measure lumbar spine and hip motion angles in clinical movement tests (trunk forward bending and prone hip extension), those with LBP were divided into a flexion LBP group and an extension LBP group. Wearable sensors were used to measure lumbar spine and hip motion angles. RESULTS: Participants with LBP had a greater hip motion angle in the early stages of movement than that of those without LBP; this was associated with the movement direction in which pain appeared. CONCLUSIONS: In individuals with LBP, the motion angles of the lumbar spine and hip joint are associated with the movement direction. Therefore, this pain subgroup and associated movement direction should be considered when evaluating and treating individuals with LBP.