Dunk Nadine M, Callaghan Jack P
Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada.
Work. 2010;35(1):3-14. doi: 10.3233/WOR-2010-0953.
Little is known about how lumbar spine movement influences mechanical changes and the potential injurious effects of prolonged flexion associated with seated postures. The purpose of this study was to examine the postural responses and pain scores of low back pain sufferers compared with asymptomatic individuals during prolonged sitting in order to understand the biomechanical factors that may be associated with sitting induced low back pain.
Sixteen participants with sitting-aggravated low back pain were age- and gender-matched with 16 asymptomatic participants. Tri-axial accelerometers were used to monitor lumbar spine angles during 90 minutes of seated computer work. Lumbar spine postures were examined using a movement pattern analysis of two types of postural adjustments, termed shifts (step-like adjustments larger than 5 degrees and fidgets (small change and return to approximately the same position).
The LBP group reported large significant increases (P < 0.0001) in low back pain while asymptomatic individuals reported little to no pain. On average, every participant fidgeted every 40 to 50 seconds. However, only the LBP sufferers demonstrated a significant increase (P=0.04) in the number of shifts over 90 minutes of seated work; the LBP group shifted every 4 minutes in the last 30 minutes of sitting compared to every 10 minutes for the asymptomatic group. LBP sufferers also demonstrated larger amplitudes of shifts and fidgets when compared to the asymptomatic group.
Greater and more frequent movement was not beneficial and did not reduce pain in individuals with pre-existing LBP. Future work to understand the biomechanical effects of proactively inducing movement may help to explain the paradox of the relationship between movement and pain.
关于腰椎运动如何影响机械变化以及与坐姿相关的长时间屈曲的潜在伤害作用，我们所知甚少。本研究的目的是检查与无症状个体相比，腰痛患者在长时间坐着时的姿势反应和疼痛评分，以了解可能与坐姿引起的腰痛相关的生物力学因素。
16名坐位加重型腰痛参与者在年龄和性别上与16名无症状参与者相匹配。在90分钟的坐着电脑工作期间，使用三轴加速度计监测腰椎角度。通过对两种姿势调整类型的运动模式分析来检查腰椎姿势，这两种姿势调整被称为移位（大于5度的阶梯状调整）和微动（小变化并回到大致相同位置）。
腰痛组报告腰痛有大幅显著增加（P < 0.0001），而无症状个体报告几乎没有疼痛。平均而言，每个参与者每40至50秒会有一次微动。然而，只有腰痛患者在90分钟的坐着工作期间移位次数有显著增加（P = 0.04）；腰痛组在坐着的最后30分钟每4分钟移位一次，而无症状组每10分钟移位一次。与无症状组相比，腰痛患者的移位和微动幅度也更大。
更大且更频繁的运动对已有腰痛的个体并无益处，也不能减轻疼痛。未来关于主动诱导运动的生物力学效应的研究可能有助于解释运动与疼痛之间关系的矛盾之处。
