ABSTRACT Background Reducing rearfoot eversion is a commonly desired effect in clinical practice to prevent or treat musculoskeletal dysfunction. Interventions that pull the lower limb into external rotation may reduce rearfoot eversion. Objective This study investigated whether the use of external rotation elastic bands, of different levels of stiffness, will decrease rearfoot eversion during walking. We hypothesized that the use of elastic bands would decrease rearfoot eversion and that the greater the band stiffness, the greater the eversion reduction. Method Seventeen healthy participants underwent three-dimensional kinematic analysis of the rearfoot and shank. The participants walked on a treadmill with and without high- and low-stiffness bands. Frontal-plane kinematics of the rearfoot-shank joint complex was obtained during the stance phase of walking. Repeated-measures ANOVAs were used to compare discrete variables that described rearfoot eversion-inversion: mean eversion-inversion; eversion peak; and eversion-inversion range of motion. Results The low-stiffness and high-stiffness bands significantly decreased eversion and increased mean eversion-inversion (p≤0.037) and eversion peak (p≤0.006) compared with the control condition. Both bands also decreased eversion-inversion range of motion (p≤0.047) compared with control by reducing eversion. The high-stiffness band condition was not significantly different from the low-stiffness band condition for any variables (p≥0.479). Conclusion The results indicated that the external rotation bands decreased rearfoot eversion during walking. This constitutes preliminary experimental evidence suggesting that increasing external rotation moments at the lower limb may reduce rearfoot eversion, which needs further testing.

CONTEXTUALIZAÇÃO: A aplicabilidade da análise de marcha foi aprimorada com a introdução da análise de componentes principais (ACP), uma técnica estatística que reduz o volume de dados, permitindo a comparação de todo o ciclo entre grupos de indivíduos. OBJETIVOS: Comparar, por meio da ACP, a cinemática da articulação do joelho durante a marcha nos planos sagital e frontal, entre mulheres idosas sem e com diagnóstico de leve a moderado de osteoartrite (OA). MÉTODOS: Participaram 38 mulheres idosas (69,6±8,1 anos) com OA de joelhos e 40 assintomáticas (70,3±7,7 anos). A cinemática foi obtida usando o sistema Qualisys Pró-reflex. RESULTADOS: O grupo OA apresentou menor velocidade da marcha e comprimento da passada (p<0,05) e caracterizou-se por maior escore de dor no WOMAC. No plano frontal, as componentes não foram significativas entre os grupos. No plano sagital, três componentes explicaram 90,7% da variância dos dados. A análise discriminante indicou que a componente 2 (CP2) e a 3 (CP3) classificaram corretamente 71,8% dos indivíduos. Entretanto, a CP3, que capta a diferença de amplitude do ângulo de flexão do joelho durante a marcha, foi a variável com maior poder de discriminação entre os grupos. CONCLUSÕES: A ACP é uma técnica estatística multivariada, efetiva para a análise das variáveis cinemáticas do ciclo da marcha. A perda de flexão de joelho na marcha do grupo com OA foi apontada como fator discriminante importante entre os grupos, sendo, portanto, uma variável que deve ser considerada na avaliação e tratamento fisioterápico da mulher idosa com OA de joelho.

BACKGROUND: The applicability of gait analysis has been implemented with the introduction of the principal component analysis (PCA), a statistical data reduction technique that allows the comparison of the whole cycle between groups of individuals. OBJECTIVES: Applying PCA, to compare the kinematics of the knee joint during gait, in the frontal and sagittal planes, between a group of elderly women with and without diagnosis in the initial and moderate stages of Osteoarthritis (OA). METHODS: A total of 38 elderly women (69.6±8.1 years) with knee OA and 40 asymptomatic (70.3±7.7 years) participated on this study. The kinematics was obtained using the Qualisys Pro-reflex system. RESULTS: The OA group showed decreased gait velocity and stride length (p<0.05) and was characterized with higher WOMAC pain score. In the frontal plane, the between-group differences of the components were not significant. In the sagittal plane, three principal components explained 99.7% of the data variance. Discriminant analysis indicated that component 2 and 3 could classify correctly 71.8% of the individuals. However, CP3, which captures the difference in the flexion knee angle magnitude during gait, was the variable with higher discrimination power between groups. CONCLUSIONS: PCA is an effective multivariate statistical technique to analyse the kinematic gait waveform during the gait cycle. The smaller knee flexion angle in the OA group was appointed as a discriminatory factor between groups, therefore, it should be considered in the physical therapy evaluation and treatment of elderly women with knee OA.