Association of Pain-Related Anxiety and Abdominal Muscle Thickness during Standing Postural Tasks in Patients with...

The purpose of this study was to evaluate the association of pain-related anxiety on abdominal muscles thickness during standing postural tasks among individuals with chronic low back pain (CLBP).

We obtained responses to a pain-related anxiety symptoms questionnaire from 50 participants with CLBP. We then separated participants into high (11 men, 14 women) and low pain-related anxiety (13 men, 12 women) groups and compared assessments of their lateral abdominal muscles thickness during standing tasks on a computerized balance assessment device, using one static level and 2 movable levels (levels 6 and 3 are represented easy and difficult tasks respectively).

We found a significant interaction effect of standing difficulty (2 levels) and abdominal muscle thickness (transverse abdominis, oblique internal and oblique external muscles) (p< .001, effect size= .7). The high pain-related anxiety group exhibited greater abdominal muscle thickness during standing postural tasks compared with the low pain-related anxiety group (p< .05, mean difference= .04-.06) except for the internal oblique muscle during the difficult standing task (p=.2).

We suggest that, among individuals with CLBP, pain-related anxiety and psychological pain-related anxiety may be possibly associated with abdominal muscles thickness during dynamic standing.