The immediate effect of a 5-minute flexed posture on lumbar spine reposition sense

Abstract

Proprioceptive control is considered important for maintenance of spinal stability and prevention of injury, and evidence exists to suggest that spinal proprioceptive structures, which are reflexive and viscoelastic, may be challenged by prolonged flexed postures. Alteration to lumbar spine position sense has been associated with low back pain patients; however, there has been little investigation into the effect different postural interventions may have on lumbar spine position sense in asymptomatic subjects. The aim of the current study was to investigate lumbar spine position sense after a 5-minute flexed posture in asymptomatic subjects. This dissertation is comprised of two main sections; a literature review followed by a manuscript for a research report that has been prepared in accordance with submission requirements for Manual Therapy. Following a familiarisation procedure, 30 asymptomatic subjects undertook two position sense tests to a neutral lumbar spine posture in the sagittal plane; one following a 5-minute fully flexed seated posture, one following a 5-minute sidelying posture, with a 15-minute interval in between tests. Absolute errors were calculated from data recorded by two orientation sensors, and compared between groups. Results showed a reduced lumbar spine reposition sense following 5-minutes in a flexed posture as compared with following 5-minutes in a sidelying position (p=0.042), mean difference 2.7° (95% CI 0.10 to 5.29°). The implications of this finding in relation to injury are discussed.