Tibialis anterior analysis from functional and architectural perspective during isometric foot dorsiflexion: a cross-sectional study of repeated measures.

Maria Ruiz Muñoz,Manuel González‐Sánchez,Antonio I Cuesta‐Vargas

doi:10.1186/s13047-015-0132-3

Abstract

BackgroundThe 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.MethodsCross-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). Outcome variables: To determine the torque, pennation angle, muscle thickness, EMGMaximalPeak, and EMGAreaUnderCurve. Statistical analysis: 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.ResultsAll outcome variables show excellent reliability. The highest correlation value was 0.955 (thickness 100 % – thickness 25 %). R2 values ranged from 0.713 (100 % MVC) to 0.588 (25 % MVC).ConclusionThe 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.

Highlights

The purpose of the present study is to establish the relationship and degree of contribution between torque and sonomiography variables, and electromyography variables (EMGAreaUnderCurve – EMGMaximalPeak) of the tibialis anterior muscle during (TA) maximal and relative isometric foot dorsiflexion (IFD)
Records of all outcome variables increased progressively with increasing contraction intensity, and mean values ranging from 17.29–21.33 mm, 4.90– 11.83°, 190.26–546.35 μV (EMGMP), 241.78–721.48 μV (EMGAUC) and 8.34–49.87 Nm (Torque) (Table 2)
The present study shows that there was a moderateto-strong correlation between the EMG activity, the architectural variables and the torque of the foot for the TA muscle

Summary

Introduction

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). The tibialis anterior (TA) muscle is the main FD muscle, and an increase in this muscle’s strength is associated with a reduction in the risk of falling [3]. Previous studies have shown that the heel strike and swing phases are the two phases with increased TA muscle activity [1, 2] In order to understand the factors that contribute to joint movements, it is common for researchers to analyse the changes of the parameters depending on strength [7, 8], both from an anatomical and a neuromotor perspective [5,6,7,8]

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