Electromyographic preactivation pattern of the gluteus medius during weight-bearing functional tasks in women with and without anterior knee pain

• Published in: Revista brasileira de fisioterapia (São Carlos (São Paulo, Brazil)) Vol. 15; no. 1; pp. 59 - 65
• Main Authors: Nakagawa, TH, Muniz, T B, Baldon, R M, Maciel, C D, Amorim, C R, Serrao, F V
• Format: Journal Article
• Language: Portuguese
• Published: 01.02.2011
• ISSN: 1413-3555

Background: Proximal factors have been proposed to influence the biomechanics of the patellofemoral joint. A delayed or diminished gluteus medius (GM) activation, before the foot contact on the ground during functional activities could lead to excessive femur adduction and internal rotation and be associated with anterior knee pain (AKP). There are few studies on this topic and the results were inconclusive, therefore, it is necessary to investigate the GM preactivation pattern during functional activities. Objective: To compare the GM electromyographic (EMG) preactivation pattern during walking, descending stairs and in single leg jump task in women with and without AKP. Methods: Nine women clinically diagnosed with AKP and ten control subjects with no history of knee injury participated in this study. We evaluated GM EMG linear envelope before the foot contact on the ground during walking and GM onset time and EMG linear envelope during descending stairs as well as in a single leg vertical jump. Mann-Whitney U tests were used to determine the between-group differences in GM EMG preactivation pattern. Results: No between-group differences were observed in GM linear envelope during walking (P=0.41), GM onset time and linear envelope during descending stairs (P=0.17 and P=0.15) and single leg jump (P=0.81 and P=0.33). Conclusions: Women with AKP did not demonstrated altered GM preactivation pattern during functional weight bearing activities. Our results did not support the hypothesis that poor GM preactivation pattern could be associated with AKP. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number ACTRN12610000115033.Original Abstract: Contextualizacao: Tem sido proposto que fatores proximais influenciam a biomecanica da articulacao femoro-patelar. Urn atraso ou diminuicao da ativacao do gluteo medio (GM) antes do contato do pe no solo, durante atividades funcionais, poderia levar a aducao e rotacao interna excessiva do femur e provocar a dor anterior do joelho (DAJ). Existem poucos estudos sobre o assunto, e os resultados nao foram conclusivos; assim, ha necessidade de estudar a pre-ativacao do GM durante atividades funcionais. Objetivo: Comparar o padrao de pre-ativacao eletromiografica (EMG) do GM durante a caminhada, descida de degraus e salto unipodal entre mulheres com e sem DAJ. Metodos: Nove mulheres com diagnostico clinico de DAJ e dez mulheres sem historia de lesao no joelho participaram do estudo. Avaliou-se a envoltoria linear do sinal EMG do GM antes do contato do pe no solo, durante caminhada; o tempo de ativacao do GM e a envoltoria linear do sinal EMG durante descida de degraus e salto unipodal. Utilizou-se o teste Mann-Whitney para determinar a diferenca intergrupos no padrao de pre-ativacao EMG do GM. Resultados: Nao se encontrou nenhuma diferenca intergrupos na envoltoria linear do GM durante caminhada (P=0.41), no tempo de ativacao e na envoltoria linear, durante descida de degraus (P=0.17 e P=0.15) e salto unipodal (P=0.81 e P=0.33). Conclusoes: Muiheres com DAJ nao apresentaram alteracoes significativas no padrao de pre-ativacao do GM durante atividades funcionais. Os presentes resultados nao sustentam a hipotese de que o pobre padrao de pre-ativacao do GM esteja envolvido na DAJ.