title: Effects of fatigue on lower limb, pelvis and trunk kinematics and muscle activation: Gender differences.
abstract: BACKGROUND
  Muscle fatigue is associated with biomechanical changes that may lead to anterior cruciate ligament (ACL) injuries. Alterations in trunk and pelvis kinematics may also be involved in ACL injury. Although some studies have compared the effects of muscle fatigue on lower limb kinematics between men and women, little is known about its effects on pelvis and trunk kinematics. The aim of the study was to compare the effects of fatigue on lower limb, pelvis and trunk kinematics and muscle activation between men and women during landing.
  
  
  METHODS
  The participants included forty healthy subjects. We performed kinematic analysis of the trunk, pelvis, hip and knee and muscle activation analysis of the gluteal muscles, vastus lateralis and biceps femoris, during a single-leg landing before and after fatigue.
  
  
  RESULTS
  Men had greater trunk flexion than women after fatigue. After fatigue, a decrease in peak knee flexion and an increase in Gmax and BF activation were observed.
  
  
  CONCLUSIONS
  The increase in the trunk flexion can decrease the anterior tibiofemoral shear force resulted from the lower knee flexion angle, thereby decreasing the stress on the ACL.
authors.affiliation: Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil.
authors.forename: Giovanna Camparis
authors.initials: GC
authors.lastname: Lessi
authors.affiliation: Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil.
authors.forename: Ana Flávia
authors.initials: AF
authors.lastname: Dos Santos
authors.affiliation: Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil.
authors.forename: Luis Fylipe
authors.initials: LF
authors.lastname: Batista
authors.affiliation: Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil.
authors.forename: Gabriela Clemente
authors.initials: GC
authors.lastname: de Oliveira
authors.affiliation: Department of Physical Therapy, Federal University of São Carlos, São Carlos, Brazil. Electronic address: fserrao@ufscar.br.
authors.forename: Fábio Viadanna
authors.initials: FV
authors.lastname: Serrão
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000502:physiology; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000502:physiology*; D010388:Pelvis / Q000502:physiology*; D016059:Range of Motion, Articular; D012737:Sex Factors; D060726:Torso / Q000502:physiology*
keywords: Anterior cruciate ligament; Biomechanics; Knee injury; Neuromuscular fatigue