title: Acute stretch perception alteration contributes to the success of the PNF "contract-relax" stretch.
abstract: BACKGROUND
  Some researchers have suggested that an alteration of stretch perception could be responsible for the success of the contract-relax (CR) stretch, a stretch technique derived from proprioceptive neuromuscular facilitation (PNF).
  
  
  OBJECTIVE
  This study was conducted to determine if the alteration of the stretch perception is a possible explanation for the range of motion (ROM) gains of the CR stretch.
  
  
  METHODS
  Eighteen subjects performed two stretches in randomized order: the slow stretch and the CR stretch.
  
  
  METHODS
  The stretch intensity was controlled. The stretch force was measured and compared between the slow stretch and CR stretch.
  
  
  RESULTS
  There was a significant difference between the stretch force that could be applied in the PNF stretch (126.0 N) and the slow stretch (108.4 N); P = 0.00086. The average stretch tolerance progressively increased with successive trials from 120.6 N in the first trial to 132.4 N in the fourth trial.
  
  
  CONCLUSIONS
  The alteration of stretch perception plays a role in the success of the CR form of PNF stretching. At least four repetitions of the CR stretch are recommended to get the greatest ROM gain.
authors.affiliation: Department of Exercise Sciences, Brigham Young University, Provo, UT, USA.
authors.forename: Ulrike H
authors.initials: UH
authors.lastname: Mitchell
authors.forename: J William
authors.initials: JW
authors.lastname: Myrer
authors.forename: J Ty
authors.initials: JT
authors.lastname: Hopkins
authors.forename: Iain
authors.initials: I
authors.lastname: Hunter
authors.forename: J Brent
authors.initials: JB
authors.lastname: Feland
authors.forename: Sterling C
authors.initials: SC
authors.lastname: Hilton
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D053581:Muscle Strength Dynamometer; D052580:Muscle Stretching Exercises; D010147:Pain Measurement; D010465:Perception; D011897:Random Allocation; D016059:Range of Motion, Articular / Q000502:physiology; D012026:Reflex, Stretch / Q000502:physiology*