title: The time course of musculotendinous stiffness responses following different durations of passive stretching.
abstract: METHODS
  Repeated-measures experimental design.
  
  
  OBJECTIVE
  To examine the acute effects of different durations of passive stretching on the time course of musculotendinous stiffness (MTS) responses in the plantar flexor muscles.
  
  
  BACKGROUND
  Stretching is often implemented prior to exercise or athletic competition, with the intent to reduce the risk of injury via decreases in MTS.
  
  
  METHODS
  Twelve subjects (mean +/- SD age, 24 +/- 3 years; stature, 169 +/- 12 cm; mass, 71 +/- 17 kg) participated in 4 randomly-ordered experimental trials: control with no stretching, 2 minutes (2min), 4 minutes (4min), and 8 minutes (8min) of passive stretching. The passive-stretching trials involved progressive repetitions of 30-second passive stretches, while the control trial involved 15 minutes of resting. MTS assessments were conducted before (prestretching), immediately after (poststretching), and at 10, 20, and 30 minutes poststretching on a Biodex System 3 isokinetic dynamometer.
  
  
  RESULTS
  MTS decreased (P<.05) immediately after all stretching conditions (2min, 4min, and 8min). However, MTS for the 2min condition returned to baseline within 10 minutes, whereas MTS after the 4min and 8min passive-stretching conditions returned to baseline within 20 minutes.
  
  
  CONCLUSIONS
  Practical durations of passive stretching resulted in significant decreases in MTS; however, these changes return to baseline levels within 10 to 20 minutes.
authors.affiliation: Biophysics Laboratory, Department of Health and Exercise Science, University of Oklahoma, Norman, OK 73019-6081, USA.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Ryan
authors.forename: Travis W
authors.initials: TW
authors.lastname: Beck
authors.forename: Trent J
authors.initials: TJ
authors.lastname: Herda
authors.forename: Holly R
authors.initials: HR
authors.lastname: Hull
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hartman
authors.forename: Pablo B
authors.initials: PB
authors.lastname: Costa
authors.forename: Jason M
authors.initials: JM
authors.lastname: Defreitas
authors.forename: Jeffery R
authors.initials: JR
authors.lastname: Stout
authors.forename: Joel T
authors.initials: JT
authors.lastname: Cramer
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D053581:Muscle Strength Dynamometer; D052580:Muscle Stretching Exercises; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted; D013710:Tendons / Q000503:physiopathology*; D013997:Time Factors