Immediate effect of application of the pressure technique to the psoas major on lumbar lordosis

Abstract

[Purpose] To demonstrate immediate alteration in lumbar lordosis and the lumbar angle in each segment after the application of the mechanical pressure technique to the psoas major muscle (PM). [Participants and Methods] In all, 34 participants were assigned to either the PM pressure technique group (n=17) or control group (n=17). Three dimensional (3D) coordinates of the 12th thoracic spinous process and lumbar spinous processes were measured with a 3D digitizer in the prone position with 15° bilateral hip extension to compare the changes in lumbar lordosis and the lumbar extension angle in each segment in both the PM pressure technique group and control group. [Results] Mann-Whitney's U test revealed no significant differences in lumbar lordosis in either group. However, the lumbar extension angle at L4 decreased significantly after the PM pressure technique compared with that before the pressure technique. Additionally, the lumbar extension angle at L4 also decreased significantly after the PM pressure technique compared with the control group. Conversely, lumbar extension angle at L1 increased significantly after the PM pressure technique compared with that before. There was no significant difference in the lumbar extension angle at L2, L3 and L5 after the PM pressure technique. [Conclusion] This study suggests that the PM pressure technique possibly attenuates PM stiffness while reducing lumbar extension in each segment.

Keywords: Lumbar lordosis; Pressure technique; Psoas major.

Fig. 1.

Applying mechanical pressure to the psoas major. A: Pressure technique to the psoas major reported by Fligg DB in 198513⁾. B: Mechanical pressure technique after identifying psoas major by ultrasonography. C: Experimental setting.

Fig. 2.

Ultrasonography of PM and RA.

Fig. 3.

Position of measurement. Participants were securely strapped onto the treatment bed with non-elastic belts in the prone position. The positions of the left and right greater trochanters were adjusted to the starting point of inclination at the treatment bed to maintain 15° extension of both left and right hip joints.

Fig. 4.

Analysis of lumbar alignment using 3D modeling software. 3-dimentional of 12th of thoracic spinous process and 1st, 2nd, 3rd, 4th, 5th of lumbar spinous process, and sacral plane were measured by 3D Microscribe and these values were integrated visually. Each angles of the lumbar vertebrae and total of lumbar lordosis were calculated by 3D modeling software. Green: Pre-pressure technique. Red: Post-pressure technique.

Fig. 5.

Schema of changing angle of lumbar lordosis.