Validity of a smartphone-based spinal assessment tool (TricuroGo) against idiag M360 and selective functional movement assessment (SFMA) in evaluating sagittal posture, mobility, and stability

BackgroundAccurate sagittal spinal assessment is crucial in physiotherapy, but current methods strike a balance between precision and practicality. Radiographic measures are valid but impractical for repeated use, whereas observational tools, such as the Selective Functional Movement Assessment (SFMA), are subjective. Device-based approaches, such as Idiag M360, are validated but costly. Smartphone-based systems, such as TricuroGo, offer accessible alternatives, although their validity remains underexplored.ObjectiveThis study evaluated TricuroGo's validity for assessing sagittal spinal posture, mobility, and stability compared with Idiag M360 and SFMA.MethodsNinety-three adults (36 men, 57 women; mean age 30.6 ± 12.3 years) underwent same-day testing with TricuroGo, Idiag M360, and SFMA. Posture, flexion, extension, and Matthias-test stability were assessed across thoracic, lumbar, and pelvic regions. Device agreement was analyzed with Bland-Altman plots, Pearson's r, or Spearman's ρ. SFMA outcomes were compared with TricuroGo by percent agreement and Spearman correlation.ResultsTricuroGo showed strong correlation with Idiag M360 for posture (r = 0.66-0.83), flexion (r = 0.56-0.88), and extension (r = 0.73-0.80), with 92-96% of Bland-Altman values within the limits. Stability associations were weaker (ρ = 0.23-0.42). Agreement with SFMA was moderate for sagittal flexion (75%, ρ = 0.47) and quadruped diagonals (74%, ρ = 0.41), but negligible for single-leg stance. Subgroup analyses revealed stronger agreement among older participants and those with a higher body mass index (BMI), with variability observed across different smartphone models.InterpretationTricuroGo provides valid and practical assessments of sagittal posture and mobility comparable to those of Idiag M360; however, its stability measure diverges from functional balance tests. It is a promising and portable solution for spinal evaluation in clinical and telehealth settings.