Muscle synergies analysis shows altered neural strategies in women with patellofemoral pain during walking.

Several studies suggest that the central nervous system coordinates muscle activation by modulating neural commands directed to groups of muscles combined to form muscle synergies. Individuals with patellofemoral pain (PFP) move differently from asymptomatic individuals. Understanding the neural strategies involved in the execution of tasks such as walking can help comprehend how the movement is planned and better understand this clinical condition. The objective of this study was to compare muscle synergies between women with and without PFP during walking. Eleven women with PFP and thirteen asymptomatic women were assessed using three-dimensional kinematics and electromyography (EMG) while walking at self-selected speed. Kinematics of the trunk, pelvis and lower limbs were analyzed through the Movement Deviation Profile. Muscle synergies were extracted from the EMG signals of eight lower limb muscles collected throughout the whole gait cycle. Kinematic differences between the two groups (p<0.001, z-score = 3.06) were more evident during loading response, terminal stance, and pre-swing. PFP group presented a lower number of muscle synergies (p = 0.037), and greater variability accounted for (VAFtotal) when using 3 (p = 0.017), 4 (p = 0.004), and 5 (p = 0.012) synergies to reconstruct all EMG signals. The PFP group also presented higher VAFmuscle for rectus femoris (p = 0.048) and gastrocnemius medialis (p = 0.019) when considering 4 synergies. Our results suggest that women with PFP show lower motor complexity and deficit in muscle coordination to execute gait, indicating that gait in PFP is the result of different neural commands compared to asymptomatic women.

Kinematic analysis of the ankle/foot complex mobility of women with PFP during weight bearing functional tests / Análise cinemática da mobilidade do complexo tornozelo/pé de mulheres com DFP durante testes funcionais de descarga de peso

Abstract: Patellofemoral pain (PFP) has been frequently associated with abnormalities in the alignment of the lower limbs and trunk, particularly during weight-bearing activities. In this context, proximal and local factors have been widely discussed. Distal factors could also be involved and need to be investigated in more detail. Our objective was to compare the foot kinematics of the ankle/foot complex in women with pronated feet and patellofemoral pain with the kinematics of asymptomatic women during the execution of anterior and lateral step down tests. Methods: Fifty women were divided into two groups: control (n=16); and patellofemoral pain (n=34). All volunteers were evaluated using three-dimensional motion capture during the forward and lateral step-down tests. For each session, nine repetitions of each clinical test were performed on the most painful limb of the women with PFP and the dominant limb of the women in the control group. The mobility of the ankle/foot complex was measured and the range of motion was calculated for all segments. The two groups were compared using multivariate analysis of variance. Results: Women in the PFP group exhibited less knee flexion and significantly greater mobility of: the hindfoot in relation to the tibia and the laboratory; the forefoot in relation to the tibia; and the forefoot in relation to the hindfoot. Conclusion: Women with PFP exhibited greater mobility of the ankle/foot complex during the anterior and lateral step down tests, when compared with asymptomatic women.

Resumo: Introdução: A dor femoropatelar (DFP) tem sido frequentemente associada a anormalidades no alinhamento dos membros inferiores e tronco, principalmente durante atividades de descarga de peso. Nesse contexto, fatores proximais e locais têm sido amplamente discutidos. Fatores distais também podem estar envolvidos e precisam ser investigados com mais detalhes. Nosso objetivo foi comparar a cinemática do complexo tornozelo/pé em mulheres com pés pronados e dor femoropatelar pormeio de cinemática tridimensional de mulheres assintomáticas durante a execução dos testes step down anterior e lateral. Métodos: Cinquenta mulheres foram divididas em dois grupos: controle (n=16); e dor patelofemoral (n=34). Todos os voluntários foram avaliados usando captura de movimento tridimensional durante os testes step down anterior e lateral. Para cada sessão, foram realizadas nove repetições de cada teste clínico no membro mais doloroso das mulheres com DFP e no membro dominante das mulheres do grupo controle. A mobilidade do complexo tornozelo/pé foi medida e a amplitude de movimento foi calculada para todos os segmentos. Os dois grupos foram comparados por meio de análise multivariada (MANOVA). Resultados: As mulheres do grupo DFP apresentaram menor flexão do joelho e mobilidade significativamente maior de: retropé em relação à tíbia e ao laboratório; do antepé em relação à tíbia; e do antepé em relação ao retropé. Conclusão: Mulheres com DFP apresentaram maior mobilidade do complexo tornozelo/pé durante os testes de step down anterior e lateral, quando comparadas com mulheres assintomáticas.

Translation, cross-cultural adaptation, and measurement properties of the Brazilian version of the Identification of Functional Ankle Instability (IdFAI) questionnaire.

OBJECTIVES: The aim of this research was to describe the translation and cultural adaptation, and to test the validity and reliability of the Brazilian version of the Identification of Functional Ankle Instability (IdFAI) questionnaire. DESIGN: This was a clinical measurement. SETTING: This research took place at the Federal University of Sao Paulo in Brazil. PARTICIPANTS: Fifty college students participated in the translation and cultural adaptation, while another 50 students participated in the measurements (validity and reliability). MAIN OUTCOME MEASURES: The cross-cultural adaptation of the Brazilian IdFAI was accomplished using standard guidelines. For the validity and reliability, the individuals were asked to complete the IdFAI tests on the same day, and after two weeks maximum. The validity was assessed by correlating the Brazilian IdFAI with the Visual Analog Scale for Instability (VAS-I), the Cumberland Ankle Instability Tool (CAIT), and the Lower Extremity Functional Scale (LEFS) using Spearman's correlation coefficient. The test-retest reliability and internal consistency were determined by using an intraclass correlation (ICC2,1) and Cronbach's α, respectively. The agreement [standard error of measurement (SEM) and minimal detectable change at 90% (MDC90)] and the floor and ceiling effects were also assessed. RESULTS: The Brazilian IdFAI had strong correlation with the CAIT and moderate correlations with the VAS-I and LEFS scale, with excellent reliability, internal consistency and agreement. No ceiling or floor effects were observed. CONCLUSION: The Brazilian IdFAI questionnaire is a valid and reliable instrument to identify functional ankle instability. It can be used in both clinical and research settings.

Repeatability of a 3D multi-segment foot model during anterior and lateral step down tests.

The aim of the present study was to analyse the reproducibility of the Oxford Foot Model (OFM) when used with healthy adults during two clinical tests, i.e., the Anterior Step Down Test (SDA) and the Lateral Step Down Test (SDL). Five healthy participants (one male and four females, 10 limbs in total) with a mean age of 22.2 (19-30) years were assessed in four sessions of tests conducted at intervals of one week. Two independent examiners performed two of the sessions of each of the tests. For each session (intra-day), nine repetitions of each clinical test (SDA and SDL) were performed. After an interval of three hours, the data were collected again. The tests were conducted again after an interval of one week using the same experimental conditions. The intra- and inter-session repeatabilities of the ranges of motion of the feet were determined according to the standard error of measurement (SEM) for each examiner and for the differences between the examiners. The repeatabilities of the results were high for both of the conducted tests. The SEM results were as follows: 0.47-1.94° for the intra-examiner assessment (SDA), 0.55-2.01° for the inter-examiner comparison (SDA), 0.44-2.43° for the intra-examiner assessment (SDL), and 0.54-1.89° for the inter-examiner comparison (SDL). The OFM model was shown to be reproducible in terms of assessing the range of motion of healthy adults during functional tests (SDA and SDL).