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 .
Preliminary Investigation of the Mechanisms Underlying the Effects of Manipulation: Exploration of a Multivariate Model Including Spinal Stiffness, Multifidus Recruitment, and Clinical Findings
Study Design . Prospect i ve case series . Objective . To examine spinal stiffness in patients with low back pain ( LBP ) receiving spinal manipulative therapy ( SMT )  , evaluate associations between stiffness characteristics and clinical outcome , and explore a multivariate model of SMT mechanisms as related to effects on stiffness , lumbar multifidus ( LM ) recruitment , and status on a  clinical prediction rule  ( CPR ) for SMT outcomes . Summary of Background Data . Mechanisms underlying the clinical effects of SMT are poorly understood . Many explanations have been proposed , but few studies have related potential mechanisms to clinical outcomes or considered multiple mechanisms concurrently . Methods . Patients with LBP were treated with two SMT sessions over 1 week . CPR status was assessed at baseline . Clinical outcome was based on the Oswestry disability index ( ODI ) . Mechanized indentation measures of spinal stiffness and ultrasonic measures of LM recruitment were taken before and after each SMT , and after 1 week . Global and terminal stiffness were calculated . Multivariate regression was used to evaluate the relationship between stiffness variables and percentage ODI improvement . Zero-order correlations among stiffness variables , LM recruitment changes , CPR status , and clinical outcome were examined . A path analysis was used to evaluate a multivariate model of SMT effects . Results . Forty-eight patients ( 54 % women ) had complete stiffness data . Significant immediate decreases in global and terminal stiffness occurred post-SMT regardless of outcome . ODI improvement was related to greater immediate decrease in global stiffness ( P = 0.025 ) , and less initial terminal stiffness ( P = 0.01 ) . Zero-order correlations and path analysis supported a multivariate model suggesting that clinical outcome of SMT is mediated by improvements in LM recruitment and immediate decrease in global stiffness . Initial terminal stiffness and CPR status may relate to outcome though their relationship with LM recruitment . Conclusion . The underlying mechanisms explaining the benefits of SMT appear to be multifactorial . Both spinal stiffness characteristics and LM recruitment changes appear to play a role
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 .