This study was undertaken to understand lumbar multifidus (LM) muscle activation as a clinical feature to predict patients with low back pain (LBP) who are likely to see improvement from stabilization (STB) exercises. A prospective, cohort study was conducted in outpatient physical therapy clinics. People with LBP were recruited for this study. Subjects (N=25) were classified as either eligible to receive STB exercises or ineligible on the basis of current clinical prediction rules for a total of six weeks of STB treatment. Prior to and following treatment, subjects underwent rehabilitative ultrasound imaging to quantify LM-muscle activation and completed disability and pain questionnaires. Analyses were performed to examine the (1) relation between LM-muscle activation and current clinical features used to predict patients with LBP likely to benefit from STB exercises, (2) LM-muscle activation between the STB-eligible and STB-ineligible groups before and after STB treatment, and (3) relation between LM-muscle activation before STB treatment and (a) disability and (b) pain outcomes after treatment for both groups. No relation was found between LM-muscle activation and the number of clinical features. Before STB treatment, LM-muscle activation between the STB-eligible and STB-ineligible groups did not differ. After STB treatment, LM-muscle activation varied between the groups; however, this interaction was because the LM-muscle activation for the STB-eligible group decreased after treatment while that for the STB-ineligible group increased after treatment. Finally, only the STB-eligible group had a significant reduction in disability after treatment; however, no relation was found between LM-muscle activation before treatment and (a) disability or (b) pain outcomes after treatment in the STB-eligible group.
LM-muscle activation does not seem to be a clinical feature that predicts patients with LBP likely to benefit from STB exercises.