title: Effect of superficial heat, deep heat, and active exercise warm-up on the extensibility of the plantar flexors.
abstract: OBJECTIVE
  Warm-up prior to static stretching enhances muscle extensibility. The relative effectiveness of different modes of warm-up, however, is unknown. The purpose of this study was to evaluate the effectiveness of superficial heat, deep heat, and active exercise warm-up prior to stretching compared with stretching alone on the extensibility of the plantar-flexor muscles.
  
  
  METHODS
  Ninety-seven subjects (59 women, 38 men) with limited dorsiflexion range of motion (ROM) were randomly assigned to 1 of 5 groups. Female subjects had a mean age of 27.6 years (SD=7.68, range=17-50), and male subjects had a mean age of 26.8 years (SD=6.87, range=18-48).
  
  
  METHODS
  The first group (group 1) was a control group and did not perform the stretching protocol. The 4 experimental groups (groups 2-5) performed a stretching protocol 3 days per week for 6 weeks. Group 2 performed the static stretching protocol only; group 3 performed active heel raises before stretching; group 4 received 15 minutes of superficial, moist heat to the plantar-flexor muscles before stretching; and group 5 received continuous ultrasound for 7 minutes before stretching. Dorsiflexion ROM measurements were taken initially and after 2, 4, and 6 weeks.
  
  
  RESULTS
  All experimental groups increased active and passive range of motion (AROM and PROM). The mean AROM/PROM differences at 6 weeks were 1.11/1.39 degrees for group 1, 4.10/6.11 degrees for group 2, 4.16/4.21 degrees for group 3, 4.38/4.90 degrees for group 4, and 6.20/7.35 degrees for group 5. The group receiving ultrasound before performing the stretching protocol (group 5) displayed the greatest increase in both AROM (6.20() and PROM (7.35().
  
  
  CONCLUSIONS
  Among the modalities tested, the use of ultrasound for 7 minutes prior to stretching may be the most effective for increasing ankle dorsiflexion ROM.
authors.affiliation: Albuquerque VA Medical Center and Lovelace Medical Center, Albuquerque, NM, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Knight
authors.forename: C R
authors.initials: CR
authors.lastname: Rutledge
authors.forename: M E
authors.initials: ME
authors.lastname: Cox
authors.forename: M
authors.initials: M
authors.lastname: Acosta
authors.forename: S J
authors.initials: SJ
authors.lastname: Hall
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D015444:Exercise / Q000502:physiology*; D005260:Female; D006358:Hot Temperature / Q000627:therapeutic use*; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D009126:Muscle Relaxation / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012680:Sensitivity and Specificity