Physical function impairment in patients with low back pain (LBP) occurs due to the influence of psychosocial factors. Only a few studies have objectively evaluated physical function. We aimed to objectively assess the physical functions of individuals subjects with LBP, and clarify the association between physical function and psychosocial factors. We enrolled 411 individuals with LBP working in special needs schools. We examined their degree of pain, and the psychosocial factors strength through the STarT Back Tool, which categorized them into the low-risk, medium-risk, and high-risk groups. We assessed their abdominal muscle endurance, lower limb muscle strength, and hip joint flexibility. The relationships between these physical functions and psychosocial factors were analyzed by logistic regression models. Those in the high-risk group had significantly lower abdominal muscle and lower limb muscle strength (p<0.001). After adjusting for confounding factors, the odds ratios of the high-risk compared to the low-risk group for low abdominal muscle endurance, lower limb muscle strength, and restricted right and left Straight Leg Raising were 5.47, 3.14, 2.65, and 3.12, respectively (95% CIs: 2.35-12.74, 1.43-6.89, 1.08-6.55, and 1.20-8.11, respectively). Therefore, the low physical function observed in the high-risk group was associated with their psychosocial factors.
Keywords: Low back pain; Physical function; Psychosocial factors; STarT Back Tool; Special needs school; Staff members.