Posture is defined as the alignment of body segments or the relative positioning of body parts for a specific activity. Traditional postural assessment is based on visual analysis, through qualitative observation of spinal curvatures and asymmetries from lateral, anterior, and posterior views. In most cases, it is subjective, as it relies heavily on the evaluator’s experience and skill to interpret the results. With current technological advancements, the use of digital photography is being considered and applied for quantitative postural assessment. Physiocode Posture is an Android application designed to identify postural and movement alterations quantitatively.

This study aimed to investigate the inter- and intra-examiner reliability of the Physiocode Posture application for the quantitative assessment of postural alterations.

This is a cross-sectional observational study conducted with 32 volunteers aged 18 to 30 years. Data collection took place on two separate days, with a seven-day interval between assessments. The Physiocode Posture app was used for quantitative postural analysis in the right and left lateral views. Images were captured using a smartphone mounted on a tripod, positioned at a standardized distance of 2.4 meters from the volunteers, with height adjusted according to each participant’s stature. Anatomical points were identified and marked with retro-reflective markers to facilitate analysis. The volunteers were instructed to maintain an orthostatic posture, with their gaze fixed on a reference point. The evaluators performed the measurements independently and underwent a familiarization phase with the application before the study began. Inter- and intra-examiner reliability was assessed using the Intraclass Correlation Coefficient (ICC), analyzed with SPSS software.

The study results suggest varying ICC values, with inter-examiner reliability generally higher than intra-examiner reliability. The reliability of the same evaluator in the right and left lateral views ranged from poor to moderate, while the reliability between different evaluators in the same views was good to excellent.

The Physiocode Posture application demonstrated good to excellent inter-examiner reliability, highlighting its potential as a quantitative postural assessment tool. However, intra-examiner reliability was lower, emphasizing the need for improvements in the use of the application and its methodology.

This study fills an important gap in the literature by investigating the reliability of Physiocode Posture in the quantitative assessment of postural alterations, a topic that has been minimally explored. By analyzing and reporting the application's reliability in different contexts, the study contributes to the consolidation of more objective and precise postural assessment methods, providing reliable data that can support clinical decision-making.