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Percorrer ESS - FIS - Artigos por autor "Alves, Leonel A. T."
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- Principal component analysis of gait Continuous Relative Phase (CRP): Uncovering lower limb coordination biomarkers for functional disability in older adultsPublication . Moreira, Juliana; Alves, Leonel A. T.; Sousa, Rúben Oliveira; Castro, Márcia; Santos, Rubim; Sousa, Andreia S. P.; Pinheiro de Sousa, Andreia Sofia; Rubim Silva Santos, Manuel; Santos Moreira, JulianaSymmetry in gait coordination reflects the balanced timing and movement between lower limb joints, which are essential for efficient locomotion and functional independence in older adults. Although gait coordination is recognized as a key indicator of aging-related adaptations and functional decline, most studies rely on isolated measures without fully addressing symmetry in intra- and interlimb coordination. This study aimed to identify principal components of gait coordination symmetry and their association with functional disability in older adults. A cross-sectional study assessed 60 community-dwelling older adults (60+), stratified by functional disability (35 non-disabled; 25 disabled). The threedimensional range of motion of lower limb joints was assessed during the gait cycle using an optoelectronic system. Intra- and intersegmental coordination was assessed by the continuous relative phase (CRP), a nonlinear measure that captures both timing and movement relationships between joint angles. Principal component analysis was applied to CRP means and coefficients-of-variation (CV) to identify key coordination principal components (PC). Of eight PC explaining 78.86% of variance, only the PC1 distinguished disability status (p = 0.007, d = 0.66). This component included sagittal-plane intrasegmental CRP mean and CV for the knee–ankle and hip–ankle. This study is novel in combining CRP-derived measures of intra- and interlimb symmetry with principal component analysis to distinguish functional disability in older adults. The findings indicate that sagittal-plane intrasegmental CRP symmetry may serve a relevant biomarker of gait impairment. By linking kinematic coordination features to functional disability, this approach complements clinical assessments and supports early identification of mobility decline in older adults.
- Principal component analysis of stair negotiation and floor transition kinematics in older adults with and without functional disability: cross-sectional studyPublication . Moreira, Juliana; Teles, Ivone da Silva; Cunha, Bruno; Félix, José; Guedes, Diana C.; Alves, Leonel A. T.; Santos, Rubim; Sousa, Andreia S P; Pinheiro de Sousa, Andreia Sofia; Rubim Silva Santos, Manuel; Santos Moreira, Juliana; Sousa Félix, José ManuelStair negotiation (ascending and descending) and transitions to level walking are complex motor tasks influenced by aging; yet the impact of functional disability on these changes remains underexplored. This study aimed to evaluate the lower limb joint positions, velocities, and the center of mass (CoM) displacement and velocity during stair negotiation and transitions in older adults with and without functional disability. Sixty community-dwelling adults, aged 60 years and older, were assessed for lower limb tridimensional joint positions and velocities during the instances of foot contact or leaving the step and foot contact or leaving the floor; the joint range of motion, angular velocity range, and the CoM displacement and angular velocity range were assessed during stair ascend and descend and transitions floor-to-stair and stair-to-floor through an optoelectronic system. Principal component analysis was used to assess 8 groups of variables to compute principal component models (I-VIII). Participants were classified as with or without disability based on functional disability indicators. Group differences were assessed using the Mann-Whitney U test. From 240 variables, 41 key parameters were identified, mainly related to hip and knee angular velocities in the sagittal plane. Significant differences between older adults with disability (n=25) and without disability (n=35) were found in 12 principal components. Older adults with functional disability showed changes in the sagittal plane hip as well as in the knee angular velocity and mediolateral and vertical CoM displacement and velocity during stair negotiation and transitions. These findings can inform targeted strategies to improve mobility and stability in this population.