title: Increased Activation Amplitude Levels of Gluteus Medius in Women During Isometric and Dynamic Conditions Following a 4-week Protocol of Low-load Eccentric Exercises.
abstract: BACKGROUND
  The dysfunction of gluteus medius (GMed) has been implicated in other musculoskeletal disorders including low back pain and lower limb injuries. The purpose of this study was to use a protocol involving low-load eccentric exercises to observe the effects on the three subdivisions of GMed activation through surface electromyography (sEMG) and digital dynamometry.
  
  
  METHODS
  Eleven female subjects having femoral instability participated in a 4-week protocol (three sessions per week/non-consecutive days). At each session, two low-load eccentric exercises (12% of maximal isometric voluntary contraction [MVIC]) in abduction, extension and external rotation were applied to the hip joint. The sEMG of the GMed subdivisions (anterior, mid and posterior) during a squat and MVIC were assessed. The digital dynamometry was also assessed during MVIC. Parametric paired t-test was used to compare the results before and after treatment with α = 0.05.
  
  
  RESULTS
  The results showed an increased sEMG activity of GMed (middle and posterior portions) during isometric voluntary contraction and squat after the protocol. No difference was noted to the anterior subdivision of GMed. Another finding was the significant difference to the dynamometry results, showing improvements to generate strength to the GMed as a whole muscle in abduction.
  
  
  CONCLUSIONS
  The 4-week exercise protocol was effective to increase the activation of the GMed middle and posterior subdivisions, improving also the capacity to generate strength as a whole muscle during the proposed tasks. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Department of Physiotherapy, Federal University of Juiz de Fora, Governador Valadares, Minas Gerais, Brazil.
authors.forename: Alexandre Carvalho
authors.initials: AC
authors.lastname: Barbosa
authors.affiliation: Department of Physiotherapy, Federal University of Valleys of Jequitinhonha and Mucuri, Diamantina, Minas Gerais, Brazil.
authors.forename: Rafaela Aparecida Nunes
authors.initials: RA
authors.lastname: Carvalho
authors.affiliation: Department of Physiotherapy, Federal University of Valleys of Jequitinhonha and Mucuri, Diamantina, Minas Gerais, Brazil.
authors.forename: Douglas Novaes
authors.initials: DN
authors.lastname: Bonifácio
authors.affiliation: Department of Physiotherapy, Federal University of Valleys of Jequitinhonha and Mucuri, Diamantina, Minas Gerais, Brazil.
authors.forename: Fábio Luiz Mendonça
authors.initials: FL
authors.lastname: Martins
authors.affiliation: Department of Health Education, Federal University of Valleys of Jequitinhonha and Mucuri, Diamantina, Minas Gerais, Brazil.
authors.forename: Michelle Cristina Sales Almeida
authors.initials: MC
authors.lastname: Barbosa
mesh_terms: D000328:Adult; D002081:Buttocks; D004576:Electromyography / Q000379:methods; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D007593:Joint Instability / Q000534:rehabilitation*; D053580:Muscle Strength / Q000502:physiology*; D018908:Muscle Weakness / Q000175:diagnosis* / Q000534:rehabilitation*; D018482:Muscle, Skeletal / Q000503:physiopathology; D018570:Risk Assessment; D012494:Sampling Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: measurement; motor learning/control; musculoskeletal; physiotherapy