Inclinometer-based measures of standing posture in older adults with low bone mass are reliable and associated with self-reported, but not performance-based, physical function

The association between posture and physical function during daily activities in people at risk for osteoporotic fracture is not clear. We report the reliability of measuring posture using the digital inclinometer and how these measures relate to performance-based and self-reported physical function. This study aims to determine the reliability of a simple clinical method for assessing spine curvatures in people with low bone mass and the association between spine curvature measures and pain, physical function (mobility/activities of daily living (ADL)) and quality of life. One rater assessed 36 high-functioning adults, aged 52-82 years, attending an outpatient osteoporosis clinic. A digital inclinometer was used to measure lumbosacral angle (S), lumbar standing posture (L), and thoracic standing posture (T) and ADL performance was assessed using the short form of the Safe Functional Motion test (SFM-6), on two occasions approximately 8.7 days apart. Participants reported average pain intensity over the past week and completed the Timed Up and Go test (TUGT) and the mini-Osteoporosis Quality of Life questionnaire (mini-OQLQ). Acceptable reliability was determined using the intraclass correlation coefficient (ICC). Associations were determined using Pearson's correlation coefficients (r) (and Spearman's rho (r (s)), for non-normal data). ICC (95 % CI) for S, L, and T = 0.91 (0.82, 0.95), 0.90 (0.82, 0.95), and 0.91 (0.84, 0.95), respectively, for test-retest reliability. Thoracic standing posture was associated with the ADL domain of the mini-OQLQ (r (s) = -0.39) and the TUGT (r = 0.42). Standing posture was not related to pain or total SFM-6 score. Digital inclinometer measures provide a quick highly reliable, valid, direct assessment of kyphosis. Use of these measures in the clinical setting is expected to facilitate identification and effective management of postural impairments (e.g., trunk extensor muscle weakness, vertebral fracture) associated with osteoporosis.