Evidence synthesis showed limited evidence supporting poor baseline transversus abdominis contraction thickness ratio as a treatment effect modifier favoring motor control exercise .
Limited evidence supported that high baseline transversus abdominis lateral slide was associated with higher pain intensity after various exercise interventions at 1-year follow-up .
However , there was limited evidence for the absence of relation between the contraction thickness ratio of transversus abdominis or anticipatory onset of lateral abdominal muscles at baseline and the short- or long-term LBP intensity after exercise interventions .
There was conflicting evidence for a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients after various conservative treatments .
Although individual reports suggest that baseline morphometry or activity of transversus abdominis or lumbar multifidus predict clinical outcome of low back pain ( LBP ) , a related systematic review is unavailable .
Therefore , this review summarized evidence regarding the predictive value of these muscular characteristics .
Association between changes in abdominal and lumbar multifidus muscle thickness and clinical improvement after spinal manipulation.
STUDY DESIGN Prospect i ve case series . OBJECTIVE To examine the relation between improved disability and changes in abdominal and lumbar multifidus ( LM ) thickness using ultrasound imaging following spinal manipulative therapy ( SMT ) in patients with low back pain ( LBP ) . BACKGROUND Although there is a growing body of literature demonstrating physiologic effects following the application of SMT , few studies have attempted to correlate these changes with clinical ly relevant outcomes . METHODS Eighty-one participants with LBP underwent 2 thrust SMT treatments and 3 assessment sessions within 1 week .  Transversus abdominis  ( TrA ) , internal oblique ( IO ) , and LM muscle thickness  was assessed during each session , using ultrasound imaging of the muscles at rest and during submaximal contractions . The Modified Oswestry Disability Index was used to quantify participants ' improvement in LBP-related disability . Stepwise hierarchical multiple linear regression and repeated- measures analysis of variance were performed to examine the multivariate relationship between change in muscle thickness and clinical improvement over time . RESULTS After controlling for the effects of age , sex , and body mass index , change in contracted LM muscle thickness was predictive of improved disability at 1 week ( P = .02 ) . As expected , larger increases in contracted LM muscle thickness at 1 week were associated with larger improvements in LBP-related disability . Contrary to our hypothesis , significant decreases in both contracted TrA and IO muscle thickness were observed immediately following SMT ; but these changes were transient and unrelated to whether participants experienced clinical improvements . CONCLUSION These findings provide evidence that clinical improvement following SMT is associated with increased thickening of the LM muscle during a submaximal task . LEVEL OF EVIDENCE Prognosis , level 4
Evidence synthesis showed limited evidence supporting poor baseline transversus abdominis contraction thickness ratio as a treatment effect modifier favoring motor control exercise .
Limited evidence supported that high baseline transversus abdominis lateral slide was associated with higher pain intensity after various exercise interventions at 1-year follow-up .
However , there was limited evidence for the absence of relation between the contraction thickness ratio of transversus abdominis or anticipatory onset of lateral abdominal muscles at baseline and the short- or long-term LBP intensity after exercise interventions .
There was conflicting evidence for a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients after various conservative treatments .
Although individual reports suggest that baseline morphometry or activity of transversus abdominis or lumbar multifidus predict clinical outcome of low back pain ( LBP ) , a related systematic review is unavailable .
Therefore , this review summarized evidence regarding the predictive value of these muscular characteristics .