Habitual pelvic posture and time spent sitting: Measurement test–retest reliability for the LUMOback device and preliminary evidence for slouched posture in individuals with low back pain

OBJECTIVES It has been difficult to monitor the pelvic position during actual daily life. However, recent developments in wearable device technologies, such as the LUMOback device, provide the possibility to evaluate habitual pelvic posture and time spent sitting during daily life. The current study aimed (1) to investigate test-retest reliability for habitual pelvic posture and time spent sitting with the LUMOback in individuals with prolonged low back pain (low back pain group) and without low back pain (control group), and (2) to preliminarily investigate differences in those measures between groups. METHODS Fifteen individuals in each group wore the LUMOback daily for 2 weeks. Intraclass correlation coefficients were calculated in each group by comparing the mean from the first week with the mean from the second week: (1) for the posture score, which is a proportion of time with neutral posture, and (2) for time spent sitting. The two measures for the first week were compared between the low back pain and control groups. RESULTS The intraclass correlation coefficients for the posture score were .82 in the low back pain group and .91 in the control group. The intraclass correlation coefficients for time spent sitting were .75 in the low back pain group and .85 in the control group. The posture score in the low back pain group (mean ± SD: 37.5% ± 10.3%) was less than that in the control group (49.6% ± 6.0%; p < .001), but there was no difference in time spent sitting between the groups (p > .05). CONCLUSIONS The current study found (1) acceptable test-retest reliability for the posture score and time spent sitting evaluated by the LUMOback device, and (2) preliminary evidence of a difference in the posture score, indicating a more slouched lumbopelvic posture in individuals with prolonged low back pain than those without low back pain.