Axial rotation of the trunk is an important movement component of many vocational tasks (e.g. manual handling), sports (e.g. golf) and activities of daily living. Combining the potentially destabilising nature of rotational movements with those of spinal flexion is considered to significantly increase the risk of spinal injury. The aim of the study was to determine the effects of changes in trunk inclination and spinal posture on the active rotational range of motion (ROM) of the trunk and pelvis. Twenty healthy individuals participated in the study and were required to perform a series of repeated maximal trunk rotations at three trunk inclinations (0°, 22.5°, 45°). At 45° forward inclination of the trunk, participants also performed maximum trunk rotations while adopting three sagittal plane spine postures (neutral, flexed, extended). Angular rotation of the trunk, pelvis and lower extremities was recorded using 3D motion analysis. A repeated-measures analysis of variance (ANOVA) tested for the main effects of trunk inclination and spinal posture on maximum active ROM of the trunk and pelvis. Repeatability of each outcome measure was investigated using interclass correlation coefficients (ICC) and Bland Altman graphs. For trunk and pelvic rotational ROM in each test position, the mean ICC's for test-retest reliability were 0.918 (CI=0.893-0.937) and 0.655 (CI=0.562-0.731), respectively. Trunk inclination in the sagittal plane had a significant effect on trunk and pelvic rotational ROM (p<0.001). As trunk inclination increased from 0° to 45°, average trunk rotational ROM increased by approximately 16% and pelvic rotational ROM decreased by approximately 40%. Spinal posture at a forward inclination of 45° was also found to have a significant effect on trunk (p<0.01) and pelvic rotational ROM (p<0.05), with a neutral spine averaging approximately 5% more trunk rotation than a flexed or extended posture. Adopting inclined, neutral spine posture appears to maximise trunk rotation. This is likely to benefit certain sport activities, such as golf. Whether this has benefits in reducing the risk of injury during vocational activities, such as manual material handling tasks, requires further investigation. These findings having important implications for the assessment of work tasks and the training and rehabilitation of those involved in sports and vocations that utilize trunk rotation.
展开▼
