title: Effects of static stretching volume and intensity on plantar flexor explosive force production and range of motion.
abstract: OBJECTIVE
  The aim of the study was to determine the effects of volume and intensity of static stretching in a warm-up on explosive force production and range of motion (ROM) of the plantar flexors.
  
  
  METHODS
  Twenty subjects performed 5 warm-ups on different days. The warm-ups contained a 5 min treadmill run and various protocols of 30 s static stretches (SS) of the plantar flexors. Stretching involved dorsi flexion just before the pain threshold, which was considered 100% intensity. The treatments that immediately followed the run were: (i) no other treatment (control); (ii) 1 min SS; (iii) 2 min SS; (iv) 4 min SS; (v) 2 min SS at 90% intensity. Ankle ROM was assessed before and after each warm-up and a concentric calf raise and drop jump (DJ) test was conducted after each warm-up.
  
  
  RESULTS
  There were no significant differences (P > 0.05) in peak force or rate of force production in the explosive calf raise between any of the warm-ups. However the run plus 2 min stretch and the run plus 4 min stretch protocols produced significantly lower (P < 0.05) DJ performance (jump height/ground contact time) than the run. The run plus 4 min stretch warm-up also produced a significantly lower DJ score than the run plus 1 min stretch warm-up. There were no significant differences between any of the warm-ups in ankle ROM.
  
  
  CONCLUSIONS
  The addition of 2-4 min of SS at 100% intensity to a run caused an impairment to fast stretch shortening cycle muscle performance. The greater impairment from the 4 min stretching condition supported a volume-effect. Two minutes of stretching at 90% intensity had no significant influence on muscle function. The addition of up to 4 min of SS to a run had no appreciable effect on ankle ROM, possibly because of the prior influence of the run.
authors.affiliation: School of Human Movement and Sport Sciences, University of Ballarat, Ballarat, Victoria, Australia. w.young@ballarat.edu.au
authors.forename: W
authors.initials: W
authors.lastname: Young
authors.forename: G
authors.initials: G
authors.lastname: Elias
authors.forename: J
authors.initials: J
authors.lastname: Power
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000842:Ankle / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D052580:Muscle Stretching Exercises; D017288:Pain Threshold / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012420:Running / Q000502:physiology