Effect of low-level laser therapy on muscle performance of young adults

Investigation of the effect of low-level laser on muscle performance in people 20 to 35 years old

A double-blinded, placebo-controlled, randomized clinical trial

Place of study performance: Sports medicine ward, Taleghani Hospital, Shahid Beheshti University of Medical Sciences Study protocol: 50 patients referring to the sports medicine ward from April 2018 to March 2019 who met the inclusion criteria, were included after explaining the study protocol and signing informed consent. The study was double-blinded. The participant didn’t know in which group is settled and the operator couldn't differentiate between active and placebo laser.

Inclusion criteria: Age between 20-35, No history of regular exercise during the past 3 months, No history of professional exercise throughout life Exclusion criteria: musculoskeletal disorders prohibiting the use of a treadmill or weight, Consuming any drug or supplements, History of Quadriceps femoris or Hamstring muscles injury

Treatment group: The participants that in the second session, before the exercise, received one session of the active laser at 810 nm wavelength and 60Hz frequency on 3 points of rectus femoris muscle, 30 seconds on each point (the laser device brand MPTC, model LMPT2000, made in Iran). The distance between the Anterior Superior Iliac Spine to the upper border of the Patella was divided into 3 equal regions and the middle point of every region was considered as an irradiation point. Control group: The participants that in the second session, before the exercise, received a laser with the probe off with the same protocol

Number of weight repetitions, the blood level of lactate, Fatigue(measured subjectively by the Rating of Perceived Scale from 6 to 20), Muscle pain (measured subjectively by scoring from 1 to 10)

To minimize the risk of selection bias, block randomization was performed. The participants, according to their Body Mass Index or BMI, were divided into two subgroups of BMI less than 25 (22 participants) and BMI equal to 25 or more (28 participants). Randomization was carried out in each subgroup separately, with a block size of 4. 2 cards of A and 2 cards of B were shuffled and randomly put together and the operator of the randomization, according to the order that the cards were arranged, assigned the participants to groups A or B. The participant who had received card A, was placed in group A and received a real laser, whereas the participant who had received card B, was placed in group B and received a placebo. All of the randomization steps were carried out by the trial operators. The participants and the operators of randomization didn't know to which group A and B cards belong.

To avoid performance bias, double-blinding was done; meaning that the participants didn’t know whether they were in the real laser or the placebo group and the laser therapy operator was unable to differentiate between active and placebo laser. The laser device was programmed by a nurse who was not in contact with the participants. Then a second operator who was blinded to the allocation of the subjects applied the phototherapy. The signals and sounds of the device in on and off mode were completely similar and the operator couldn’t differentiate whether it is on or off. So, both participants and operators were blinded to the type of treatment.

Using the data is allowed after the participants are non-recognizable

Beginning the data access 6 months after the results are published

All researchers in university associations

Data analysis is allowed for use in meta-analyses and clinical review studies

for accessing the data please send an e-mail to the address h.anahita64@yahoo.com Dr. Nina Hazegh. Name and the telephone number, the association, posting address, e-mail of the person who has requested for the data is necessary.

after receiving the request and recognizing the identity of the person who has sent the request, the data will be sent in a week