Reliability and Validity Measurement ofSagittal Lumbosacral Quiet Standing Posture witha Smartphone Application in a Mixed Population of183 College Students and Personnel

Accurate recording of spinal posture with simple and accessible measurement devices in clinical practice may lead to spinal loadingoptimization in occupations related to prolonged sitting and standing postures. Therefore, the purpose of this study was to establishthe level of reliability of sagittal lumbosacral posture in quiet standing and the validity of the method in differentiating between maleand female subjects, establishing in parallel a normative database. 183 participants (83 males and 100 females), with no current lowback or pelvic pain, were assessed using the “iHandy Level” smartphone application. Intrarater reliability (3 same-day sequentialmeasurements) was high for both the lumbar curve (ICC2,1: 0.96, SEM: 2.13∘,andMDC95%:5.9∘)andthesacralslope(ICC2,1: 0.97,SEM: 1.61∘,andMDC95%: 4.46∘) sagittal alignment. Data analysis for each gender separately confirmed equally high reliability forboth male and female participants. Correlation between lumbar curve and sacral slope was high (Pearson’s𝑟=0.86,𝑝<0.001).Between-gender comparisons confirmed the validity of the method to differentiate between male and female lumbar curve andsacral slope angles, with females generally demonstrating greater lumbosacral values (𝑝<0.001). The “iHandy Level” applicationis a reliable and valid tool in the measurement of lumbosacral quiet standing spinal posture in the sagittal plane