title: Different Effect of Local and General Fatigue on Knee Joint Stiffness.
abstract: This study aimed to investigate the influence of locally and generally induced fatigue on the stiffness properties of the knee joint.
  
  
  
  Twenty-two male (24.9 ± 4.5 yr, 1.78 ± 0.06 m, 75.4 ± 6.4 kg, 23.9 ± 1.8 kg·m) and 18 female (21.1 ± 1.5 yr, 1.66 ± 0.05 m, 63.4 ± 6.5 kg, 22.9 ± 2.5 kg·m) amateur athletes participated. Peak torque (PT) of the knee extensor musculature, muscle stiffness (MS) of the vastus lateralis, and musculoarticular stiffness (MAS) of the knee joint were assessed pre- and postlocally and generally induced fatigue (undertaken on two separate days with a 1-wk interval).
  
  
  
  Males were characterized by higher values of MAS, relaxed and contracted MS, normalized PT (PT/body mass), and normalized MAS (MAS/external load) irrespective of time point (P < 0.05).
  
  
  
  Contracted MS increased more (P < 0.01) and normalized PT decreased more (P = 0.03) in males than in females postfatigue. Significant increases occurred in MAS in females (P = 0.01); relaxed MS (males, P < 0.001; females, P < 0.001), contracted MS (males, P < 0.001; females, P = 0.04), and normalized MAS (males, P = 0.001; females, P = 0.01) in both sexes; and normalized contracted MS (contracted MS/external load) in males (P < 0.001). Normalized PT decreased significantly in males (P < 0.01) postfatigue.
  
  
  
  Contracted MS (P = 0.01) and MAS (P = 0.05) decreased significantly in males post-fatigue.
  
  
  
  The stiffness properties of the knee joint are influenced by locally and generally induced fatigue, with different responses being observed in males and females.
authors: 1School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, IRELAND; 2The No. 2 Clinical Medicine School, Nanjing University of Chinese Medicine, Nanjing, Jiang Su Province, CHINA; and 3Institute for Sport and Health, University College Dublin, Dublin, IRELAND.
authors: Dan
authors: D
authors: Wang
authors: Giuseppe
authors: G
authors: DE Vito
authors: Massimiliano
authors: M
authors: Ditroilo
authors: Eamonn
authors: E
authors: Delahunt
mesh_terms: D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D012737:Sex Factors; D055815:Young Adult