Low Back Muscle Hardness of Different Trunk Angles in Sitting and Standing

Abstract

[Purpose] To examine the differences in muscle hardness among postures maintaining different anterior trunk angles in sitting and standing.[Subjects] The subjects were 19 healthy males. [Methods] In sitting and standing, the hardness of the multifidus of the lumbar spine was measured at 7 trunk anterior inclination angles from 0 to 60˚. The inclination angles of the sacrum and femur, and hip flexion angle were compared among the trunk angles, and the relative and absolute reliabilities of the muscle hardness values, and the muscle hardness of the lumbar region according to the exercise task was investigated. [Results] Compared to standing, the sacrum had a more posterior tilt in the sitting position. The reliability and validity of the muscle hardness measures were high, and at low angles of trunk inclination, the hardness of the multifidus showed greater values in the sitting position. [Conclusion] It is possible to confirm the hardness of the lumbar spinal muscles with a muscle hardness meter, but attention should be paid to the influence of sacral tilt when investigating hardness in the sitting position compared to standing.

Effects of movement from a postural maintenance position on lumbar hemodynamic changes

“…In accordance with earlier studies 1 , 2 ) , the first exercise task (flexion-extension exercise) involved the subject gradually moving the trunk, 10° at a time, from an upright, resting trunk position of 0° flexion, as measured by an electric goniometer (NorAngle, Noraxon, Scottsdale, AZ, USA), to a position of maximum flexion, and then returning to a position of 0° flexion (re-upright) by extending the trunk. The second task (extension-flexion exercise) involved the subject gradually moving the trunk, 10° at a time, from an upright position to a position of maximum trunk extension, and then returning to a position of 0° flexion (re-upright) by flexing the trunk.…”

“…In the current super-aging society, work-related lower back pain is common in caregivers who are frequently required to adopt a flexed posture with the trunk tilted forward. In previous studies, we examined lower back muscle activity and tissue stiffness during trunk flexion while standing and sitting and found more constant muscle activity and increased tissue stiffness at shallower flexion angles among participants in seated positions compared to those of participants in standing positions 1 , 2 ) . Excessive increase in tissue stiffness leads to impaired blood flow, and the resultant lumbar ischemia is associated with lower back pain.…”