title: A new concept for evaluating muscle function in the lower extremities in cases of low back pain syndrome in anamnesis.
abstract: BACKGROUND
  There are difficulties in objective evaluation of activity of the muscles in the lower extremities of patients after successful treatment of sciatica and pseudosciatica, when no clear clinical symptoms are detected. However, the existence of some muscle dysfunction can be hypothesised and its detection was the aim of the study.
  
  
  OBJECTIVE
  Recordings from chosen lower extremity muscles during standing were performed as supplementary differential diagnosis in evaluation of these patients. EMG in standing positions constitutes a new methodological approach not described in detail.
  
  
  METHODS
  Twenty patients (11 after sciatica and 9 after sciatica-like episodes) were enrolled into the study. On the day of examination, clinical and electroneurographical (ENG; M and F waves tests) studies showed no pathology. The percentage of maximal voluntary contraction (MVC) defined muscle activity during standing. Mean amplitude and number of changes in muscle activity (fluctuations) were measured in surface electromyography recordings (sEMG) during normal standing and tandem positions.
  
  
  CONCLUSIONS
  Activity of proximal lower extremity muscles expressed as percentage of MVC was bilaterally increased in patients after sciatica in normal standing position, compared with results from the group of healthy volunteers (N=9). Patients after sciatica were also characterized with a significant increase of mean sEMG amplitude, recorded especially in distal muscles on the affected side during tandem position. This pathological change was related to decrease in 'fluctuations' frequency in patients after sciatica (P<0.001) more than after pseudosciatica (P<0.01) groups in both standing positions, compared to parameters of healthy volunteers. Sciatica and pseudosciatica in anamnesis cause different abnormal patterns of lower extremity muscle activity during standing positions when recorded with surface EMG.
authors: Department of Rheumatology and Rehabilitation, University of Medical Sciences, Poznań, Poland.
authors: Przemysław
authors: P
authors: Lisiński
authors: Department of Pathophysiology of Locomotor Organs, University of Medical Sciences in Poznań, Poland.
authors: Juliusz
authors: J
authors: Huber
authors: Department of Rheumatology and Rehabilitation, University of Medical Sciences in Poznań, Poland.
authors: Jagoda
authors: J
authors: Ciesielska
authors: Department of Pathophysiology of Locomotor Organs, University of Medical Sciences in Poznań, Poland.
authors: Joanna
authors: J
authors: Lipiec
authors: Department of Pathophysiology of Locomotor Organs, University of Medical Sciences in Poznań, Poland.
authors: Aleksandra
authors: A
authors: Kulczyk
authors: Department of Rheumatology and Rehabilitation, University of Medical Sciences in Poznań, Poland.
authors: Agata
authors: A
authors: Bandosz
authors: Department of Allergology and Environmental Hazards, Institute of Rural Health, Lublin, Poland.
authors: Wioletta
authors: W
authors: Żukiewicz-Sobczak
authors: Department of Clinical Psychology, University of Medical Sciences in Poznań, Poland.
authors: Ewa
authors: E
authors: Mojs
authors: Department of Rheumatology and Rehabilitation, University of Medical Sciences in Poznań, Poland.
authors: Włodzimierz
authors: W
authors: Samborski
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology*; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology* / Q000503:physiopathology; D055958:Piriformis Muscle Syndrome / Q000175:diagnosis / Q000503:physiopathology; D011187:Posture; D012585:Sciatica / Q000175:diagnosis* / Q000503:physiopathology