Abstract
BACKGROUND: This parallel randomised control trial assessed feasibility of an exercise intervention for individuals with low back pain and maladaptive changes in lateral abdominal muscle contraction. Feasibility was assessed considering participant retention, program adherence and a preliminary evaluation of intervention efficacy. METHODS: Sixty adults (40 female, 20 male, average 54.2 years of age) with persistent low back pain and maladaptive changes in lateral abdominal muscle contraction were randomly assigned to fully or partially individualised versions of the 12-week program. All participants received motor control and graded activity exercise individualised to their low back pain symptoms, impairments and functional goals. Additionally, participants in the fully individualised group were asked what types of exercise they enjoy, and this informed the graded activity prescription. Lateral abdominal outcome measures included endurance and ultrasound imaging (muscle thickness at rest and during contraction, transversus abdominis slide), manual palpation and pressure biofeedback unit measures of contraction. Clinical outcomes included pain intensity (Numeric Rating Scale), disability (Roland Morris Disability Questionnaire), function (Pain Specific Functional Scale), physical activity (International Physical Activity Questionnaire) and lumbar instability (Lumbar Instability Questionnaire). Outcomes were measured at baseline, at the end of the intervention and clinical outcomes were measured again three months after the intervention concluded. Linear mixed effects models were used to compare the effects of the intervention within and between groups. RESULTS: Retention and exercise compliance rates were 81% and > 85% (86% control group, 87% experimental group) respectively. Participants in both groups achieved improved lumbar instability, disability, pain intensity, function, physical activity, lateral abdominal muscle endurance and contraction post intervention. The fully individualised group demonstrated greater between group improvements in function (mean [95%CI]: - 2.577 [- 3.239, - 1.915] 12 weeks, - 2.592 [- 3.254, - 1.930] 3 months) and physical activity (mean [95%CI]: - 790.834 [- 1712.05, 130.382] 12 weeks, - 1080.748 [- 2001.964, - 159.532] 3 months). CONCLUSIONS: The intervention demonstrated improvements in clinical outcomes, and acceptable exercise compliance. However, the intervention did not meet retention feasibility criteria to proceed to an adequately powered trial. Modifications to improve retention including incorporating group activities are required. Following modifications, an adequately powered trial is required to determine the efficacy of the intervention. TRIAL REGISTRATION: This trial was prospectively registered on the Australian and New Zealand Clinical Trial Registry (ACTRN12622001284752 30 September 2022).