STUDY DESIGN: Clinical measurement, criterion standard. OBJECTIVES: To investigate the validity of real-time ultrasound imaging (USI) to measure individual anterior hip muscle cross-sectional area. BACKGROUND: The hip flexor muscles are important for hip joint function and could be affected by joint pathology or injury. Objectively documenting individual anterior hip muscle size can be useful in identifying muscle size asymmetry and monitoring treatment efficacy for patients with hip problems. USI offers a novel method of measuring individual muscle size in the clinic, but its validity in measuring the anterior hip muscles has not been investigated. METHODS: Nine healthy participants (5 males, 4 females) underwent imaging of their iliopsoas, sartorius, and rectus femoris muscles with USI and magnetic resonance imaging. Bilateral muscle cross-sectional areas were measured on images from both modalities. RESULTS: There was no significant difference (P>.05) in mean cross-sectional area measurements from USI and magnetic resonance imaging for each muscle. Agreement between measurements was high for the iliopsoas (left: intraclass correlation coefficient [ICC_3,1] = 0.86; 95% confidence interval [CI]: 0.51, 0.97; right: ICC_3,1 = 0.88; 95% CI: 0.57, 0.97), sartorius (left: ICC_3,1 = 0.82; 95% CI: 0.41, 0.96; right: ICC_3,1 = 0.81; 95% CI: 0.39, 0.95), and rectus femoris (left: ICC_3,1 = 0.85; 95% CI: 0.49, 0.96; right: ICC_3,1 = 0.89; 95% CI: 0.61, 0.97). Reliability of measuring each muscle with USI was high between 2 trials (ICCs_3,1 = 0.84 to 0.94). CONCLUSION: USI is a valid measure of iliopsoas, sartorius, and rectus femoris muscle size in healthy people, as long as a strict measurement protocol is followed.

J Orthop Sports Phys Ther 2010;40(9):577-581, Epub 13 May 2010. doi:10.2519/jospt.2010.3286

KEY WORDS: iliopsoas, MRI, rectus femoris, reliability, sartorius

STUDY DESIGN: Single-blinded quasi-experimental study. OBJECTIVE: To investigate the ability of elite football players with and without low back pain (LBP) to voluntarily draw-in the abdominal wall. BACKGROUND: While there has been considerable debate regarding the contribution of the transversus abdominis (TrA) muscle to control the lumbar spine and pelvis, there is evidence that retraining motor control of the deep trunk muscles is commensurate with decreases in LBP. Magnetic resonance imaging (MRI) has been used to assess the TrA muscle during the draw-in maneuver, with the contraction of the TrA muscle reducing the circumference of the trunk. Impairments in performance of the draw-in maneuver have been shown in people with LBP. METHODS: Forty-three elite players from a team in the Australian Football League were allocated to 3 groups: those with "no LBP," "a history of LBP but no current LBP," or "current LBP." MRI was used to image the cross-sectional area (CSA) of the trunk at the level of the L3-4 disc at the start and end of the draw-in maneuver. RESULTS: There was a significant decrease in the CSA of the trunk with the performance of the draw-in maneuver (P<.001). Subjects in the "no LBP" group were better able to "draw-in" the abdominal wall than subjects with current LBP (P = .015). CONCLUSIONS: This study provides evidence of an altered ability to draw-in the abdominal wall in footballers with current LBP. Retraining contraction of the TrA muscle may constitute one part of an exercise-therapy approach for athletes with current LBP.

J Orthop Sports Phys Ther 2010;40(1):4-10, Epub 3 December 2009. doi:10.2519/jospt.2010.3177

KEY WORDS: abdomen, lumbar spine, MRI

J Orthop Sports Phys Ther. 2007:37(8):467-471; published online 30 May 2007. doi:10.2519/jospt.2007.2417

KEY WORDS: internal oblique muscle, lumbar stabilization, real-time ultrasound imaging, sonography, transversus abdominis muscle