title: Limb blood flow after class 4 laser therapy.
abstract: BACKGROUND
  Laser therapy is purported to improve blood flow in soft tissues. Modulating circulation would promote healing by controlling postinjury ischemia, hypoxia, edema, and secondary tissue damage. However, no studies have quantified these responses to laser therapy.
  
  
  OBJECTIVE
  To determine a therapeutic dose range for laser therapy for increasing blood flow to the forearm.
  
  
  METHODS
  Crossover study.
  
  
  METHODS
  Controlled laboratory setting.
  
  
  METHODS
  Ten healthy, college-aged men (age = 20.80 ± 2.16 years, height = 177.93 ± 3.38 cm, weight = 73.64 ± 9.10 kg) with no current history of injury to the upper extremity or cardiovascular conditions.
  
  
  METHODS
  A class 4 laser device was used to treat the biceps brachii muscle. Each grid point was treated for 3 to 4 seconds, for a total of 4 minutes. Each participant received 4 doses of laser therapy: sham, 1 W, 3 W, and 6 W.
  
  
  METHODS
  The dependent variables were changes in blood flow, measured using venous occlusion plethysmography. We used a repeated-measures analysis of variance to analyze changes in blood flow for each dose at 2, 3, and 4 minutes and at 1, 2, 3, 4, and 5 minutes after treatment. The Huynh-Feldt test was conducted to examine differences over time.
  
  
  RESULTS
  Compared with baseline, blood flow increased over time with the 3-W treatment (F(3,9) = 3.468, P < .011) at minute 4 of treatment (2.417 ± 0.342 versus 2.794 ± 0.351 mL/min per 100 mL tissue, P = .032), and at 1 minute (2.767 ± 0.358 mL/min per 100 mL tissue, P < .01) and 2 minutes (2.657 ± 0.369 mL/min per 100 mL tissue, P = .022) after treatment. The sham, 1-W, and 6-W treatment doses did not change blood flow from baseline at any time point.
  
  
  CONCLUSIONS
  Laser therapy at the 3-W (360-J) dose level was an effective treatment modality to increase blood flow in the soft tissues.
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, PO Box 118205, Gainesville, FL 32611, USA. klarkin@hhp.ufl.edu
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Larkin
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Martin
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Zeanah
authors.forename: Jerry M
authors.initials: JM
authors.lastname: True
authors.forename: Randy W
authors.initials: RW
authors.lastname: Braith
authors.forename: Paul A
authors.initials: PA
authors.lastname: Borsa
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D005542:Forearm / Q000098:blood supply*; D006439:Hemodynamics; D006801:Humans; D028022:Low-Level Light Therapy; D008297:Male; D012039:Regional Blood Flow; D016896:Treatment Outcome; D055815:Young Adult