title: Tibialis anterior analysis from functional and architectural perspective during isometric foot dorsiflexion: a cross-sectional study of repeated measures.
abstract: BACKGROUND
  The purpose of the present study is to establish the relationship and degree of contribution between torque and sonomiography variables (pennation angle - muscle thickness), and electromyography variables (EMGAreaUnderCurve - EMGMaximalPeak) of the tibialis anterior muscle during (TA) maximal and relative isometric foot dorsiflexion (IFD). Secondary aim: To determine the measurement's reliability.
  
  
  METHODS
  Cross-sectional study. 31 participants (15 men; 16 women) performed IFD at different intensities (100, 75, 50, and 25 %) of the maximal voluntary contraction (MVC) (three times for each intensity).
  
  
  METHODS
  To determine the torque, pennation angle, muscle thickness, EMGMaximalPeak, and EMGAreaUnderCurve.
  
  
  METHODS
  In order to test the measurement's reliability, Cronbach's alpha and standard error of the measurement were determined. An inferential analysis was carried out using Pearson correlations(r). For each contraction intensity, a multiple regression analysis was performed, where the dependent variable was torque and the independent variables were EMGAreaUnderCurve, EMGMaximalPeak, muscle thickness and pennation angle.
  
  
  RESULTS
  All outcome variables show excellent reliability. The highest correlation value was 0.955 (thickness 100 % - thickness 25 %). R (2) values ranged from 0.713 (100 % MVC) to 0.588 (25 % MVC).
  
  
  CONCLUSIONS
  The outcome variables demonstrated excellent reliability in terms of measuring IFD at different intensities. The correlations between all outcome variables were moderate-to-strong. TA functional and architectural variables have a significant impact on the torque variance during IFD at different intensities.
authors.affiliation: Departamento de Enfermería y Podología, Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Málaga, Málaga, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Ruiz Muñoz
authors.affiliation: Departamento Ciencias de la Salud. Instituto de Investigación Biomédica de Málaga (IBIMA), Universidad de Jaén, Málaga, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: González-Sánchez
authors.affiliation: Departamento de Fisioterapia, Facultd de Ciencias de la Salud, Instituto de Investigacion Biomedica de Malaga (IBIMA), Grupo Clinimetria F-14 Universidad de Malaga, Andalucia Tech, Malaga, Spain ; School of Clinical Sciences at Queensland University, Brisbane, Australia.
authors.forename: Antonio I
authors.initials: AI
authors.lastname: Cuesta-Vargas
keywords: Ankle; Anterior Tibial Muscle; Electromyography; Multiple Regression Analysis; Ultrasonography