The relationship of transversus abdominis and lumbar multifidus clinical muscle tests in patients with chronic low back pain.

Introduction: Previous research of transversus abdominis (TrA) and multifidus muscle function in the presence of chronic low back pain (LBP) has investigated these muscles in isolation. In clinical practice, it is assumed that a relationship exists between these muscles and so they are often assessed and rehabilitated together. However, no studies have tested or documented this association. This study aimed to examine the relationships between clinical muscle testing and other measures taken in the course of a clinical assessment at a back clinic.

Methods: This retrospective chart audit examined the files of 82 patients (40 Males, 42 Females) for results of clinical tests of TrA and multifidus muscle contraction, multifidus muscle size measurements and other clinical measures such as distribution of pain and pain on manual examination.

Results: The ability to contract multifidus was related to the ability to contract TrA with the odds of a good contraction of multifidus being 4.5 times higher for patients who had a good contraction of TrA. A poor ability to contract multifidus was related to poor TrA contraction. Patients with unilateral LBP had more multifidus muscle asymmetry (11.6%) than those with bilateral/central pain (0.01%) and had a poor multifidus contraction on the affected side (p < 0.01). No other significant relationships were found.

Discussion & Conclusion: Current clinical practice of assessment and rehabilitation of both TrA and multifidus muscles in patients with chronic LBP is supported by the findings of this study. Future studies may investigate if a neurophysiological relationship exists between these muscles.