title: Lumbar multifidus and erector spinae electromyograms during back bridge exercise in time and frequency domains.
abstract: BACKGROUND
  Muscle activity is studied during trunk stabilization exercises using electromyograms (EMG) in time domain. However, the frequency domain analysis provides information that would be important to understand fatigue process.
  
  
  OBJECTIVE
  To assess EMG of lumbar multifidus (LM) and erector spinae (ES) muscles, in time and frequency domains, during back bridge exercise.
  
  
  METHODS
  Nineteen healthy young men performed the exercise for one minute and EMG was monitored by surface electromyography. Normalized root mean square (RMS) value and spectral median frequency (MF) were compared between beginning and final epochs of test. The dynamics of the MF during whole test was also obtained by short-time Fourier transform.
  
  
  RESULTS
  RMS values were about 30% of maximum voluntary contraction, and LM muscle showed greater MF than ES, which did not decrease at the final of exercise. However, the slope of MF was significant mainly for LM.
  
  
  CONCLUSIONS
  Muscle activation of 30% is sufficient to keep lumbar stability and is suitable to improve muscular endurance. The significance of MF slope without decreasing at the final of exercise indicates challenging muscular endurance without imply on high fatigability. Due to lower muscular demand, this exercise might be recommended for trunk stabilizing for low back pain patients.
authors.affiliation: Laboratório de Fisiologia do Exercício e Biomecânica (LaFEB), Departamento de Educação Física e Esportes, Escola Naval, Marinha do Brazil, Brasil.|Programa de Engenharia Biomédica, COPPE, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: Roger Gomes Tavares
authors.initials: RG
authors.lastname: Mello
authors.affiliation: Laboratório de Biomecânica, Programa de Pós-Graduação em Educação Física, EEFD, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: Igor Rodrigues
authors.initials: IR
authors.lastname: Carriço
authors.affiliation: Programa de Engenharia Biomédica, COPPE, Universidade Federal do Rio de Janeiro, Brasil.|Laboratório de Biomecânica, Programa de Pós-Graduação em Educação Física, EEFD, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: Thiago Torres
authors.initials: TT
authors.lastname: da Matta
authors.affiliation: Programa de Engenharia Biomédica, COPPE, Universidade Federal do Rio de Janeiro, Brasil.|Laboratório de Biomecânica, Programa de Pós-Graduação em Educação Física, EEFD, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: Jurandir
authors.initials: J
authors.lastname: Nadal
authors.affiliation: Programa de Engenharia Biomédica, COPPE, Universidade Federal do Rio de Janeiro, Brasil.|Laboratório de Biomecânica, Programa de Pós-Graduação em Educação Física, EEFD, Universidade Federal do Rio de Janeiro, Brasil.
authors.forename: Liliam Fernandes
authors.initials: LF
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D004576:Electromyography; D005081:Exercise Therapy / Q000379:methods*; D005583:Fourier Analysis; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D064170:Paraspinal Muscles / Q000502:physiology*; D055815:Young Adult
keywords: Back muscles; electromyography; exercise therapy; rehabilitation