Palmer Center for Chiropractic Research, Palmer College of Chiropractic, 1000 Brady St, Davenport, IA, USA.
Palmer Center for Chiropractic Research, Palmer College of Chiropractic, 1000 Brady St, Davenport, IA, USA.
J Bodyw Mov Ther. 2023 Apr;34:19-27. doi: 10.1016/j.jbmt.2023.04.004. Epub 2023 Apr 6.
Differential movement, or shear strain (SS), between layers of thoracolumbar fascia is reduced with chronic low back pain. To provide a foundation for clinical research involving SS, this study assessed temporal stability and the effect of paraspinal muscle contraction on SS in persons with chronic low back pain.
We used ultrasound imaging to measure SS in adults self-reporting low back pain ≥1 year. Images were obtained by placing a transducer 2-3 cm lateral to L2-3 with participants lying prone and relaxed on a table moving the lower extremities downward 15°, for 5 cycles at 0.5 Hz. To assess paraspinal muscle contraction effects, participants raised the head slightly from the table. SS was calculated using 2 computational methods. Method 1 averaged the maximum SS from each side during the third cycle. Method 2 used the maximum SS from any cycle (2-4) on each side, prior to averaging. SS was also assessed after a 4-week no manual therapy period.
Of 30 participants (n = 14 female), mean age was 40 years; mean BMI 30.1. Mean (SE) SS in females with paraspinal muscle contraction was 66% (7.4) (method 1) and 78% (7.8) (method 2); 54% (6.9) (method 1) and 67% (7.3) (method 2) in males. With muscles relaxed, mean SS in females was 77% (7.6) (method 1) or 87% (6.8) (method 2); 63% (7.1) (method 1) and 78% (6.4) (method 2) in males. Mean SS decreased 8-13% in females and 7-13% in males after 4-weeks CONCLUSION: Mean SS in females was higher than males at each timepoint. Paraspinal muscle contraction temporarily reduced SS. Over a 4-week no-treatment period, mean SS (with paraspinal muscles relaxed) decreased. Methods less likely to induce muscle guarding and enabling assessment with broader populations are needed.
胸腰筋膜各层之间的相对运动或剪应变（SS）在慢性下腰痛患者中会减少。为了为涉及 SS 的临床研究提供基础，本研究评估了慢性下腰痛患者 SS 的时间稳定性和竖脊肌收缩的影响。
我们使用超声成像测量报告腰痛≥1 年的成年人的 SS。参与者仰卧在桌子上，将探头放置在 L2-3 旁 2-3cm 处，让下肢向下移动 15°，以 0.5Hz 频率进行 5 个循环。为了评估竖脊肌收缩的影响，参与者稍微抬头离开桌子。使用 2 种计算方法计算 SS。方法 1 是在第 3 个周期中平均每侧的最大 SS。方法 2 在每侧的第 2-4 个周期中使用最大 SS，然后再取平均值。在 4 周不进行手法治疗后也评估了 SS。
在 30 名参与者（n=14 名女性）中，平均年龄为 40 岁，平均 BMI 为 30.1。女性在竖脊肌收缩时的平均 SS（SE）为 66%（7.4）（方法 1）和 78%（7.8）（方法 2）；男性为 54%（6.9）（方法 1）和 67%（7.3）（方法 2）。在肌肉放松时，女性的平均 SS 为 77%（7.6）（方法 1）或 87%（6.8）（方法 2）；男性为 63%（7.1）（方法 1）和 78%（6.4）（方法 2）。在女性中，SS 在 4 周后降低了 8-13%，在男性中降低了 7-13%。结论：在每个时间点，女性的平均 SS 均高于男性。竖脊肌收缩会暂时降低 SS。在 4 周的不治疗期间，放松竖脊肌时的平均 SS （SS）会降低。需要采用不太可能引起肌肉保护和能够在更广泛人群中进行评估的方法。
