title: Immediate effects of quantified hamstring stretching: hold-relax proprioceptive neuromuscular facilitation versus static stretching.
abstract: OBJECTIVE
  To compare the immediate effects of a hold-relax proprioceptive neuromuscular facilitation stretching (HR-PNF) versus static stretch (SS) on hamstring flexibility in healthy, asymptomatic subjects.
  
  
  METHODS
  Thirty subjects (13 female; mean age 25.7 ± 3.0, range 22-37) without excessive hamstring muscle flexibility were randomly assigned to one of two stretch groups: HR-PNF or SS.
  
  
  METHODS
  The left leg was treated as a control and did not receive any intervention. The right leg was measured for ROM pre- and post-stretch interventions, with subjects receiving randomly assigned interventions one week apart. Data were analyzed with a 3 (intervention: HR-PNF, SS, control) × 2 (time: pre and post) factorial ANOVA with repeated measures and appropriate post-hoc analyses.
  
  
  RESULTS
  A significant interaction was observed between intervention and time for hamstring extensibility, F(2,58) = 25.229, p < .0005. Main effect of intervention for the tested leg was not significant, p = .782 indicating that there was no difference between the two stretch conditions. However, main effect for time was significant (p < .0005), suggesting that hamstring extensibility (for both stretching conditions) after intervention was greater than before.
  
  
  CONCLUSIONS
  No significant differences were found when comparing the effectiveness of HR-PNF and SS techniques. Both stretching methods resulted in significant immediate increases in hamstring length.
authors.affiliation: Department of Physical Therapy, School of Allied Health Sciences, University of Nevada Las Vegas, USA. louie.puentedura@unlv.edu
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Puentedura
authors.forename: Peter A
authors.initials: PA
authors.lastname: Huijbregts
authors.forename: Shelley
authors.initials: S
authors.lastname: Celeste
authors.forename: Dale
authors.initials: D
authors.lastname: Edwards
authors.forename: Alastair
authors.initials: A
authors.lastname: In
authors.forename: Merrill R
authors.initials: MR
authors.lastname: Landers
authors.forename: Cesar
authors.initials: C
authors.lastname: Fernandez-de-Las-Penas
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016001:Confidence Intervals; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D007866:Leg / Q000502:physiology*; D008297:Male; D052580:Muscle Stretching Exercises; D011434:Proprioception / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult