The Lumbar Spine Instability Questionnaire (LSIQ) is a 15-item questionnaire that can be used in prioritizing management strategies between physical factors from a biomedical perspective and cognitive factors from a psychosocial perspective. If only some of the 15 questions can capture the big picture of the LSIQ, the efficiency of clinical reasoning could be improved. Therefore, the purpose of this study was to examine the test-retest reliability of each question item on the Japanese LSIQ and identify the main question items on the Japanese LSIQ through principal component analysis. The prevalence-adjusted bias-adjusted kappa (PABAK) was calculated from the data of 50 patients with low back pain for whom LSIQ data could be collected twice, at least one day before the initial physical therapy and immediately before the initial physical therapy. No item had a PABAK value of less than 0.4. Next, we analyzed the Japanese LSIQ data of 107 patients with low back pain and six components. The cumulative contribution rate was about 65.0%, and the contribution rate of the first component was only 22.1%. These results indicate that the Japanese LSIQ is reliable, but that it would be difficult to use it for clinical reasoning on a subset of items.

It is unclear whether the general public living in the community in Japan seek educational content and biopsychosocial approaches from physical therapists for the acquisition of self-management strategies for low back pain (LBP) as in other developed physical therapy countries. The purpose of this study was to investigate, using semi-structured interviews, general population demands of physical therapists for LBP and self-management strategies for controlling LBP. Thematic analysis based on the data of 19 participants proposed the following five themes as general population demands of physical therapists: social perspectives, biophysical perspectives, treatment proposal, selection of physical therapy modalities, and collaboration with a medical doctor. Thematic analysis identified three themes for self-management strategies: passive treatment continuation behavior, health-directed behavior, and self-monitoring and insight. Even in Japan, it is possible that there is demand among the general population for LBP prevention strategies through educational and biopsychosocial approaches to LBP.