<b>Association of Quadratus Lumborum Muscle Tightness with Low Back Pain Due to Prolonged Sitting among Young Adults: A Cross-Sectional Study</b>

Background: Low back pain is increasingly reported among young adults, particularly in those exposed to prolonged sitting and sedentary academic routines. Quadratus lumborum muscle tightness may contribute to altered lumbar mechanics, pain, and functional limitation, but its association with sitting-related low back pain in young adults remains insufficiently documented. Objective: To assess the association between quadratus lumborum muscle tightness, pain intensity, and functional disability among young adults with low back pain and prolonged sitting exposure. Methods: This cross-sectional observational study included 94 participants aged 18–25 years recruited through non-probability purposive sampling from two campuses of the University of Management and Technology, Sialkot, Pakistan. Eligible participants had low back pain and reported sitting for more than six hours per day. Quadratus lumborum tightness was assessed clinically using seated side-bending, hip hike, and deep palpation procedures. Pain intensity and disability were assessed using the Numeric Pain Rating Scale and Oswestry Disability Index, respectively. Data were analyzed using Shapiro–Wilk testing, chi-square analysis, Mann–Whitney U testing, and Spearman correlation. Results: Quadratus lumborum tightness was present in 67 participants (71.3%). Participants with tightness showed higher pain and disability categories than those without tightness. Quadratus lumborum tightness was significantly associated with ODI category, χ²(3) = 10.567, p = 0.014, and NPRS category, χ²(3) = 29.073, p < 0.001. Spearman analysis showed positive correlations between quadratus lumborum tightness and ODI category (r = 0.328, p = 0.001) and NPRS category (r = 0.537, p < 0.001). Conclusion: Quadratus lumborum muscle tightness was common and significantly associated with higher pain and disability categories among young adults with low back pain and prolonged sitting exposure