Trunk muscle function is not associated with low back pain in young people whilst muscle morphology is associated with back strength in young adult males: Results from cross-sectional and prospective analyses

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University of New Brunswick


PURPOSE: Examine the relationships between trunk muscle function and low back pain and lumbar multifidus muscle morphology and back muscle function in young people. METHODS: Data from a prospective study of young people aged 16 to 21. We measured back muscle endurance and strength and abdominal muscle strength with standard tests, and quantified intramuscular fat in the lumbar multifidus muscles with magnetic resonance imaging. RESULTS: Crude and adjusted analyses showed no associations between trunk muscle function and impactful low back pain. Average (Beta Coefficient [95% CI] = -.51 [-.92, -.11]) and maximum (Beta Coefficient [95% CI] = -.37 [-.67, -.07]) intramuscular fat was associated with back muscle strength in boys but not in girls. CONCLUSIONS: These findings cast doubt on the aetiological role of muscle function in the development of back pain. The relation between trunk muscle morphology and back strength may be sex-specific.