Background and Objectives This study, which was approved by the University's Ethical committee, was conducted to investigate the effectiveness of Combined Low Intensity Laser Therapy/Phototherapy (CLILT) in alleviating the signs and symptoms of Delayed Onset Muscle Soreness (DOMS) over an 11‐day period. Study Design/Materials and Methods Thirty‐six subjects (18 M:18 F) were randomly allocated, under strictly controlled double‐blind conditions, to one of three experimental conditions: Control, Placebo, and CLILT (660–950 nm; 11 J/cm2; pulsed at 73 Hz). DOMS was induced in a standardised fashion in the non‐dominant elbow flexors using repeated eccentric contractions until exhaustion was reached. Subjects returned on five consecutive days, and two days during the following week, for treatment according to group, and assessment of outcome variables including range of motion, pain, and tenderness. Results While analysis of results using repeated measures and one factor ANOVA with post‐hoc tests showed significant changes in all variables over time (P < 0.05) as a result of the induction procedure, there were no significant differences observed between groups. Conclusions CLILT failed to show any beneficial treatment effect on DOMS, at least at the parameters used here. These results therefore provide no evidence for the claimed biostimulating effects of such therapy. Lasers Surg. Med. 24:223–230, 1999. © 1999 Wiley‐Liss, Inc.

Background and Objectives: This study, which was approved by the University's Ethical committee, was conducted to investigate the effectiveness of Combined Low Intensity Laser Therapy/Phototherapy (CLILT) in alleviating the signs and symptoms of Delayed Onset Muscle Soreness (DOMS) over an 11-day period. Study Design/Materials and Methods: Thirty-six subjects (18 M: 18 F) were randomly allocated, under strictly controlled doubleblind conditions, to one of three experimental conditions: Control, Placebo, and CLILT (660-950 nm; 11 J/cm 2 ; pulsed at 73 Hz). DOMS was induced in a standardised fashion in the nondominant elbow flexors using repeated eccentric contractions until exhaustion was reached. Subjects returned on five consecutive days, and two days during the following week, for treatment according to group, and assessment of outcome variables including range of motion, pain, and tenderness. Results: While analysis of results using repeated measures and one factor ANOVA with post-hoc tests showed significant changes in all variables over time (P < 0.05) as a result of the induction procedure, there were no significant differences observed between groups. Conclusions: CLILT failed to show any beneficial treatment effect on DOMS, at least at the parameters used here. These results therefore provide no evidence for the claimed biostimulating effects of such therapy. Lasers Surg. Med. 24:223-230, 1999.