2026-10-012026-10-012026MOREIRA, Lana Paula Cardoso. Avaliação do controle de tronco em lactentes típicos por meio da cinemetria e acelerometria: elaboração e validação de constructo de um modelo biomecânico integrado. 2026. 53f. Dissertação (Mestrado em Reabilitação e Desempenho Funcional) - Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará, Belém, 2026.https://portaldaposgraduacao.uepa.br/handle/riuepa/312AbertoEquilíbrio postural, Lactente, Biomecânica, Acelerometria, Postural balance, Infant, Biomechanics, AccelerometryDissertaçãoCiências BiológicasTrunk control development in infants is a dynamic, segmental, and non-linear process, which is fundamental for the acquisition of independent motor milestones. Although kinematics is considered the gold standard for biomechanical analysis, the use of inertial measurement units (IMUs) integrated into devices such as smartphones emerges as an innovative, accessible, and ecologically valid alternative for quantitative assessment in clinical and community contexts. Objective: To develop an exploratory biomechanical protocol to quantify reactive trunk control in typically developing infants and to analyze the agreement between response time measurements obtained by smartphone accelerometry and optoelectronic kinematics. Methods: This is a methodological, quantitative study with an analytical observational design, conducted with 16 typically developing infants aged between 4 and 9 months. The protocol was developed based on the Segmental Assessment of Trunk Control (SATCo), applying standardized external perturbations at the axillary and pelvic levels. The reactive response time was captured simultaneously by a 3D kinematics system and by accelerometry via a smartphone attached to the thorax (Samsung Galaxy A10; Momentum® application). Statistical analysis included the Shapiro-Wilk test to verify data normality, Pearson's correlation to analyze the correlation between methods, Mean Absolute Error (MAE), and Bland-Altman analysis to evaluate the agreement between the measurement systems. Results: There was no statistically significant difference between the means of the two methods in any of the evaluated conditions (𝑝 > 0.05), indicating the absence of systematic bias. Accelerometry demonstrated high clinical accuracy at the axillary level (MAE < 0.07s). Both instruments were sensitive in detecting the temporal precedence of the axillary level relative to the pelvic level (𝑝 < 0.001), corroborating the cephalo-caudal maturational development pattern. Conclusion: The pelvic level presented higher absolute errors compared to the axillary level, signaling the need to refine the signal filtering protocol for this segment in future studies. Smartphone accelerometry showed satisfactory agreement with kinematics for measuring reactive response time, demonstrating potential as an objective and low-cost tool for the assessment of infant postural development.PPGREAB - Avaliação e intervenção terapêutica nos sistemas neuromuscular