Research Article Reliability and Validity Measurement of Sagittal Lumbosacral Quiet Standing Posture with a Smartphone Application in a Mixed Population of 183 College Students and Personnel George A. Koumantakis, 1,2 Maria Nikoloudaki, 2 Sara Thacheth, 2 Kalliroi Zagli, 2 Konstantina Bitrou, 2 Andreas Nigritinos, 2 and Leon Botton 2 1 401 General Army Hospital of Athens, Pan. Kanellopoulou 1, Athens, Greece 2 Athens Metropolitan College, Health Sciences Faculty, School of Physiotherapy, Athens, Greece Correspondence should be addressed to George A. Koumantakis; gkoymantakis@metropolitan.edu.gr Received 28 July 2016; Accepted 29 September 2016 Academic Editor: Panagiotis Korovessis Copyright © 2016 George A. Koumantakis et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Accurate recording of spinal posture with simple and accessible measurement devices in clinical practice may lead to spinal loading optimization in occupations related to prolonged sitting and standing postures. herefore, the purpose of this study was to establish the level of reliability of sagittal lumbosacral posture in quiet standing and the validity of the method in diferentiating between male and female subjects, establishing in parallel a normative database. 183 participants (83 males and 100 females), with no current low back or pelvic pain, were assessed using the “iHandy Level” smartphone application. Intrarater reliability (3 same-day sequential measurements) was high for both the lumbar curve (ICC 2,1 : 0.96, SEM: 2.13 ∘ , and MDC 95% : 5.9 ∘ ) and the sacral slope (ICC 2,1 : 0.97, SEM: 1.61 ∘ , and MDC 95% : 4.46 ∘ ) sagittal alignment. Data analysis for each gender separately conirmed equally high reliability for both male and female participants. Correlation between lumbar curve and sacral slope was high (Pearson’s  = 0.86,  < 0.001). Between-gender comparisons conirmed the validity of the method to diferentiate between male and female lumbar curve and sacral slope angles, with females generally demonstrating greater lumbosacral values ( < 0.001). he “iHandy Level” application is a reliable and valid tool in the measurement of lumbosacral quiet standing spinal posture in the sagittal plane. 1. Introduction Sagittal lumbopelvic alignment is an important physical assessment parameter for the orthopaedic [1] and physical therapy [2] health professionals. Posture is deined as the alignment and positioning of the body in relation to gravity, center of mass, or base of support in order to minimize load [3] and prevention against potential injury [2]. he sagittal curvatures of the spine [4] and the sagittal alignment of the pelvis [5] represent the basic mechanism for maintaining an eicient standing position [6]. Postural deviations from the “neutral” range [7] are con- sidered to be a signiicant reason for the appearance of back pain, according to several studies [8–12]. Diferent methods to assess sagittal spinal posture have been used, in the light of poor reliability demonstrated with visual assessment of posture [13], with X-rays on one hand being the gold-stand- ard assessment method [4], however not routinely used for postural evaluation due to associated costs and subject irradiation. Vrtovec et al. [4] in an excellent review analysed all potential X-ray based methods of posture analysis. Indeed, the accuracy of radiographic methods of postural assessment is high, with interrater Intraclass Correlation Coeicient (ICC) and Minimum Detectable Change (MDC) values of 0.98 and 3.9 ∘ , respectively, for lumbar curve assessments in a relevant study [14]. Photographic methods have also been used comparatively to X-ray methods, with acceptable cor- relations between the 2 methods in determining the size of the Cobb angle and the length of lordosis; however, values with the photogrammetric method were systematically lower compared to X-rays [15]. Hindawi Publishing Corporation Advances in Orthopedics Volume 2016, Article ID 3817270, 9 pages http://dx.doi.org/10.1155/2016/3817270