title: Skinfold thickness affects the isometric knee extension torque evoked by Neuromuscular Electrical Stimulation.
abstract: BACKGROUND
  Subcutaneous adipose tissue may influence the transmission of electrical stimuli through to the skin, thus affecting both evoked torque and comfort perception associated with neuromuscular electrical stimulation (NMES). This could seriously affect the effectiveness of NMES for either rehabilitation or sports purposes.
  
  
  OBJECTIVE
  To investigate the effects of skinfold thickness (SFT) on maximal NMES current intensity, NMES-evoked torque, and NMES-induced discomfort.
  
  
  METHODS
  First, we compared NMES current intensity, NMES-induced discomfort, and NMES-evoked torque between two subgroups of subjects with thicker (n=10; 20.7 mm) vs. thinner (n=10; 29.4 mm) SFT. Second, we correlated SFT to NMES current intensity, NMES-induced discomfort, and NMES-evoked knee extension torque in 20 healthy women. The NMES-evoked torque was normalized to the maximal voluntary contraction (MVC) torque. The discomfort induced by NMES was assessed with a visual analog scale (VAS).
  
  
  RESULTS
  NMES-evoked torque was 27.5% lower in subjects with thicker SFT (p=0.01) while maximal current intensity was 24.2% lower in subjects with thinner SFT (p=0.01). A positive correlation was found between current intensity and SFT (r=0.540, p=0.017). A negative correlation was found between NMES-evoked torque and SFT (r=-0.563, p=0.012). No significant correlation was observed between discomfort scores and SFT (rs=0.15, p=0.53).
  
  
  CONCLUSIONS
  These results suggest that the amount of subcutaneous adipose tissue (as reflected by skinfold thickness) affected NMES current intensity and NMES-evoked torque, but had no effect on discomfort perception. Our findings may help physical therapists to better understand the impact of SFT on NMES and to design more rational stimulation strategies.
authors.affiliation: Faculdade de Educação Física, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Flávia V A
authors.initials: FV
authors.lastname: Medeiros
authors.affiliation: Faculdade de Ciências da Saúde, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Amilton
authors.initials: A
authors.lastname: Vieira
authors.affiliation: Departamento de Fisioterapia, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Rodrigo L
authors.initials: RL
authors.lastname: Carregaro
authors.affiliation: Faculdade de Educação Física, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: Martim
authors.initials: M
authors.lastname: Bottaro
authors.affiliation: Neuromuscular Research Laboratory, Zurich, Switzerland.
authors.forename: Nicola A
authors.initials: NA
authors.lastname: Maffiuletti
authors.affiliation: Departamento de Fisioterapia, Universidade de Brasília, Brasília, DF, Brazil.
authors.forename: João L Q
authors.initials: JL
authors.lastname: Durigan
mesh_terms: D004558:Electric Stimulation / Q000379:methods; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D007717:Knee; D018482:Muscle, Skeletal / Q000502:physiology*; D052097:Quadriceps Muscle / Q000502:physiology*; D012885:Skinfold Thickness; D019415:Torque