Acute Effects of Centrally- And Unilaterally-Applied Posterior–Anterior Mobilizations of the Lumbar Spine on Lumbar Range of Motion, Hamstring Extensibility and Muscle Activation

BACKGROUND: Lumbar mobilizations are used to clinically treat the lumbar and hamstring region. Evidence is limited regarding the effectiveness of specific mobilization methods, however. OBJECTIVE: To compare central and unilateral posterior–anterior mobilizations (CPA, UPA) of the lumbar spine on lumbar and hamstring range of motion (ROM), and muscle activity (sEMG). METHODS: Twenty participants received CPA, UPA, or no mobilization (CON) on separate occasions (crossover design). Post-treatment outcome measures were ROM during active lumbar flexion (ALF) and active knee extension (AKE), as well as sEMG of the Erector Spinae (ES) and Biceps Femoris (BF) during these movements. RESULTS: sEMG was possibly to very likely lower following CPA (mean difference range = -5% to -21%) and UPA (-7% to -36%), while ROM was most likely greater (-12% to 25% & -17% to 24%, respectively). Most sEMG measures were possibly to likely lower following UPA versus CPA (-18% to -11%), while AKE ROM was possibly greater (-5.5%). Differences in ES sEMG (-2.5%) and ROM (-1.4%) during ALF were unclear and most likely trivial, respectively. CONCLUSIONS: CPA and UPA mobilizations increase lumbar and hamstring ROM whilst reducing local muscle activity. These effects appear to be greater for UPA mobilizations when compared with CPA.