Background Rapid flexion movement increases the loading on the spine and it increases the risk of injuries1. In asymptomatic subjects lumbar-dominant and pelvis-dominant patterns of movement during trunk flexion have been observed2,3. However, little information about lumbar spine kinematics has been provided.
Objectives To find out whether exhibiting different lumbopelvic patterns of movement during trunk flexion affects the kinematics of the lumbar spine in terms of velocity of motion.
Methods Differential lumbar spine and pelvis angular displacement during the time course of a standardised sagittal trunk flexion from an upright position was recorded with an electromagnetic tracking device in 32 asymptomatic females (22.65±3.5 years). Range of motion (ROM) (degrees) for the lumbar spine, pelvis and average angular velocity (degrees/sec) for the entire movement were calculated. Subjects were divided into groups according to moving more in the lumbar spine than in pelvis, group1 (n=17) and vice-versa moving more in the pelvis (at the hip joint) than in lumbar spine, group2 (n=15). The one-way MANOVA followed by F test showed significant differences in lumbar spine velocity between groups.
Results The lumbopelvic pattern of movement is shown for both groups in the figure. Average angular velocity (degrees/sec) for the spine was significantly (p<0.01) greater in group 1 (18.7±3.8) than in 2 (13.1±2.4).
Conclusions Changes in the lumbopelvic pattern of movement bring about differences in lumbar spine velocity of motion. Consequently, the risk of injury for the spine may be different for both groups and clinical implications may be different as well.
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Acknowledgement This study has been supported by the following grants:Ref. FIS2001–0070–01, Ref. TIC2001–2786-C02–02, Ref. AP2001–376
Disclosure of Interest None declared