title: Effect of balance training on neuromuscular function at rest and during isometric maximum voluntary contraction.
abstract: OBJECTIVE
  This study was directed to investigate the neuromuscular function of the plantar flexors and tibialis anterior (TA) before and after 8 weeks of balance training.
  
  
  METHODS
  Twenty-six young adult subjects were randomly assigned to an intervention group and a control group. During neuromuscular testing, rate of torque development (RTD), isometric maximum voluntary torque (iMVT) and muscle activation were measured. Triceps surae muscle activation and TA muscle co-activation were assessed by normalized root mean square of the EMG signal during the initial phase of contraction (0-100, 0-200 ms) and maximum voluntary contraction (MVC) of the plantar flexors. Furthermore, evoked spinal reflex responses of the soleus muscle (H-reflex evoked at rest and during MVC, V-wave), peak twitch torques induced by electrical stimulation at rest and balance performance were evaluated.
  
  
  RESULTS
  We found a significant difference between groups in RTD of the plantar flexors during MVC in the time interval 0-100 ms [37.0 N m s(-1) (4.2-69.9 N m s(-1), P = 0.029)]. This change was accompanied by reduced antagonistic muscle co-activity. The normalized H-reflex of the soleus muscle at rest as well as the sway of the center of pressure during balance performance assessment were significantly lower for the intervention group compared with controls. The training intervention had no effect on iMVT, normalized muscle activity of the plantar flexors, normalized muscle activity of TA, normalized V-wave and normalized H-reflex evoked during MVC.
  
  
  CONCLUSIONS
  Data suggest that balance training reduced antagonistic muscle co-activity at the onset of triceps surae contraction and, in turn, increased isometric explosive voluntary strength of the plantar flexors.
authors.affiliation: Department of Exercise Science, University of Rostock, Ulmenstrasse 69, 18057, Rostock, Germany, martin.behrens@uni-rostock.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Behrens
authors.forename: Anett
authors.initials: A
authors.lastname: Mau-Moeller
authors.forename: Franziska
authors.initials: F
authors.lastname: Wassermann
authors.forename: Rainer
authors.initials: R
authors.lastname: Bader
authors.forename: Sven
authors.initials: S
authors.lastname: Bruhn
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006181:H-Reflex / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D055815:Young Adult