title: Gastrocnemius inflexibility on foot progression angle and ankle kinetics during walking.
abstract: BACKGROUND
  Gastrocnemius inflexibility is a major problem in many orthopedic and neurological patients. Clinically, inflexible gastrocnemius muscles interfere with the performance of functional abilities and associate with many overuse injuries of the lower extremity. The purpose of this study was to investigate the effects of the gastrocnemius inflexibility on the foot progression angle and ankle kinetics during walking.
  
  
  METHODS
  There were 50 subjects, 23 patients with the inflexible gastrocnemius and 27 normal subjects, included in this investigation. Participants were asked to walk at two preset cadences of 100 steps/min and 140 steps/min. Data were collected from a motion analysis system and force plates. Kinematic and kinetic variables of gait were computed and analyzed.
  
  
  RESULTS
  Compared with the control group, greater toe-out foot progression angle (P=0.001, effect size=0.314) and knee external rotation (P=0.008, effect size=0.136) were found in the inflexible group during stance phase. Furthermore, significant greater plantarflexion moment (P=0.032, effect size=0.093) and medial ground reaction force (P=0.009, effect size=0.135) during midstance were discovered in the inflexible group.
  
  
  CONCLUSIONS
  The present results indicate that gastrocnemius inflexibility might bring about the changes in the joint angles, ankle moments and ground reaction forces. The abnormal joint alignment in the lower extremities and greater force upon joint tissue might be significant for the clinical considerations on soft tissue injuries for the patients with inflexible gastrocnemius muscles.
authors.affiliation: Department of Physical Therapy, HungKuang University, Shalu, Taichung County, Taiwan.
authors.forename: Shyi-Kuen
authors.initials: SK
authors.lastname: Wu
authors.affiliation: Department of Occupational Therapy, Chung Shan Medical University, Taichung County, Taiwan.
authors.forename: Shu-Zon
authors.initials: SZ
authors.lastname: Lou
authors.affiliation: Department of Physical Therapy, I-Shou University, Kaohsiung County, Taiwan.
authors.forename: Hsin-Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Physical Therapy, HungKuang University, Shalu, Taichung County, Taiwan.
authors.forename: Han-Yu
authors.initials: HY
authors.lastname: Chen
authors.affiliation: Department of Physical Therapy, I-Shou University, Kaohsiung County, Taiwan. Electronic address: you0902@isu.edu.tw.
authors.forename: Jia-Yuan
authors.initials: JY
authors.lastname: You
mesh_terms: D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D005528:Foot / Q000502:physiology; D005684:Gait / Q000502:physiology; D006801:Humans; D007700:Kinetics; D007719:Knee Joint / Q000502:physiology; D008297:Male; D009127:Muscle Rigidity / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology*; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Flexibility; Gait; Gastrocnemius; Kinematics; Kinetics