Evaluation of Psoas Major and Quadratus Lumborum Recruitment Using Diffusion-Weighted Imaging Before and After 5 Trunk Exercises.

Study Design Controlled laboratory study, with a pretest-posttest design. Background Diffusion-weighted imaging is a noninvasive magnetic resonance imaging technique that can be used to assess the recruitment of the psoas major (PM) and quadratus lumborum (QL). The recruitment of these muscles during trunk exercises has not been evaluated. Objective To evaluate the diffusion of water movement in several trunk muscles using diffusion-weighted imaging before and after specific trunk exercises and thereby to understand the level of recruitment of each muscle during each exercise. Methods Nine healthy male participants performed the right side bridge, knee raise, and 3 front bridges, including the hand-knee, elbow-knee, and elbow-toe bridges. Diffusion-weighted imaging was performed before and after each exercise. After scanning, the apparent diffusion coefficient (ADC) map was constructed, and ADC values of the rectus abdominis, lateral abdominal muscles, QL, PM, and back muscles were calculated. Results The right PM following the elbow-toe bridge demonstrated the largest increase in ADC values, a change significantly greater than that demonstrated by the hand-knee bridge (P<.001) and side bridge (P = .002) exercises. The ADC change in the right QL following the side bridge exercise was significantly larger than that of other exercises (P<.008). Conclusion Of the 5 exercises investigated, the elbow-toe bridge and side bridge exercises elicit the greatest recruitment of the PM and QL, respectively. J Orthop Sports Phys Ther 2017;47(2):108-114. Epub 5 Nov 2016. doi:10.2519/jospt.2017.6730.