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 .
Covariate adjustment increased power in randomized controlled trials: an example in traumatic brain injury.
OBJECTIVE We aim ed to determine to what extent covariate adjustment could affect power in a r and omized controlled trial ( RCT ) of a heterogeneous population with traumatic brain injury ( TBI ) . STUDY DESIGN AND SETTING We analyzed 14-day mortality in 9,497 participants in the Corticosteroid R and omization After Significant Head Injury ( CRASH ) RCT of corticosteroid vs. placebo . Adjustment was made using logistic regression for baseline covariates of two vali date d risk models derived from external data ( International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury [ IMPACT ] ) and from the CRASH data . The relative sample size ( RESS ) measure , defined as the ratio of the sample size required by an adjusted analysis to attain the same power as the unadjusted reference analysis , was used to assess the impact of adjustment . RESULTS Corticosteroid was associated with higher mortality compared with placebo ( odds ratio=1.25 , 95 % confidence interval=1.13 - 1.39 ) . RESS of 0.79 and 0.73 were obtained by adjustment using the IMPACT and CRASH models , respectively , which , for example , implies an increase from 80 % to 88 % and 91 % power , respectively . CONCLUSION Moderate gains in power may be obtained using covariate adjustment from logistic regression in heterogeneous conditions such as TBI . Although analyses of RCTs might consider covariate adjustment to improve power , we caution against this approach in the planning of RCTs
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 .