title: Shank Muscle Strength Training Changes Foot Behaviour during a Sudden Ankle Supination.
abstract: BACKGROUND
  The peroneal muscles are the most effective lateral stabilisers whose tension braces the ankle joint complex against excessive supination. The purpose of this study was to identify the morphological and biomechanical effects of two machine-based shank muscle training methods.
  
  
  METHODS
  Twenty-two healthy male recreationally active sports students performed ten weeks of single-set high resistance strength training with 3 training sessions per week. The subjects conducted subtalar pronator/supinator muscle training (ST) with the right leg by using a custom-made apparatus; the left foot muscles were exercised with machine-based talocrural plantar and dorsiflexor training (TT). Muscle strength (MVIC), muscle volume and foot biomechanics (rearfoot motion, ground reaction forces, muscle reaction times) during a sudden ankle supination were recorded before and after the intervention.
  
  
  RESULTS
  Compared to TT, ST resulted in significantly higher pronator (14% vs. 8%, P<0.01) and supinator MVIC (25% vs. 12%, P<0.01). During sudden foot inversions, both ST and TT resulted in reduced supination velocity (-12%; P<0.01). The muscle reaction onset time was faster after the training in peroneus longus (PL) (P<0.01). Muscle volume of PL (P<0.01) and TA (P<0.01) increased significantly after both ST and TT.
  
  
  CONCLUSIONS
  After both ST and TT, the ankle joint complex is mechanically more stabilised against sudden supinations due to the muscle volume increase of PL and TA. As the reduced supination velocities indicate, the strength training effects are already present during free-fall. According to a sudden ankle supination in standing position, both machine-based dorsiflexor and pronator strength training is recommended for enhancing the mechanical stability of the ankle.
authors.affiliation: Biomechanics Laboratory, Institute of Sport and Movement Sciences, University Duisburg Essen, Essen, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Hagen
authors.affiliation: Institute of Neuroradiology, University of Frankfurt, Frankfurt, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Lescher
authors.affiliation: Biomechanics Laboratory, Institute of Sport and Movement Sciences, University Duisburg Essen, Essen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Gerhardt
authors.affiliation: Department of Orthopaedic Sports Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Lahner
authors.affiliation: Institute for Diagnostic and Interventional Radiology, Neuroradiology and Nuclear Medicine, Stiftungsklinikum Mittelrhein Koblenz, Koblenz, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Felber
authors.affiliation: Biomechanics Laboratory, Institute of Sport and Movement Sciences, University Duisburg Essen, Essen, Germany.
authors.forename: Ewald M
authors.initials: EM
authors.lastname: Hennig
mesh_terms: D000328:Adult; D000842:Ankle / Q000502:physiology*; D000843:Ankle Joint / Q000502:physiology*; D005528:Foot / Q000502:physiology*; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D055070:Resistance Training; D013484:Supination / Q000502:physiology*