title: Increased active hamstring stiffness after exercise in women with a history of low back pain.
abstract: OBJECTIVE
  To compare active hamstring stiffness in female subjects with and without a history of low back pain (LBP) after a standardized 20-min aerobic-exercise session.
  
  
  METHODS
  Case control.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  12 women with a history of recurrent episodes of LBP (age = 22.4 ± 2.1 y, mass = 67.1 ± 11.8 kg, height = 167.9 ± 8 cm) and 12 matched healthy women (age = 21.7 ± 1.7 y, mass = 61.4 ± 8.8 kg, height = 165.6 ± 7.3 cm). LBP subjects reported an average 6.5 ± 4.7 on the Oswestry Disability Index.
  
  
  METHODS
  Participants walked at a self-selected speed (minimum 3.0 miles/h) for 20 min. The treadmill incline was raised 1% grade per minute for the first 15 min. During the last 5 min, participants adjusted the incline of the treadmill so they would maintain a moderate level of perceived exertion through the end of the exercise protocol.
  
  
  METHODS
  During session 1, active hamstring stiffness, hamstring and quadriceps isometric strength, and concurrently collected electromyographic activity were recorded before and immediately after the exercise protocol. For session 2, subjects returned 48-72 h after exercise for repeat measure of active hamstring stiffness.
  
  
  RESULTS
  Hamstring active stiffness (Nm/rad) taken immediately postexercise was not significantly different between groups. However, individuals with a history of recurrent LBP episodes presented significantly increased hamstring stiffness 48-72 h postexercise compared with controls. For other outcomes, there was no group difference.
  
  
  CONCLUSIONS
  Women with a history of recurrent LBP episodes presented greater active hamstring stiffness 48-72 h after aerobic exercise.
authors: Ithaca College, Ithaca, NY, USA.
authors: Rebecca J
authors: RJ
authors: Bedard
authors: Kyung-Min
authors: KM
authors: Kim
authors: Terry L
authors: TL
authors: Grindstaff
authors: Joseph M
authors: JM
authors: Hart
mesh_terms: D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D017116:Low Back Pain / Q000503:physiopathology*; D053580:Muscle Strength / Q000502:physiology; D009129:Muscle Tonus / Q000502:physiology*; D018482:Muscle, Skeletal / Q000293:injuries / Q000503:physiopathology*; D013848:Thigh; D055815:Young Adult