Low Level Laser Therapy in Muscle Fatigue and Muscle Recovery
Condition: Muscle; Fatigue, Heart; Skeletal Muscle Recovery
MeSH terms: Fatigue
Study type: Interventional

Summary: 
      Muscle fatigue and muscle recovery after exercise are recent areas of research involving Low
      Level Laser Therapy (LLLT) and many factors remain unknown, such as optimal doses, power and
      application parameters, mechanisms of action, effects on long-term exercise and the long-term
      effects on skeletal muscle recovery.

      The present research project aims to assess the effects of long-term recovery of LLLT in
      skeletal muscle after exercise and identify the optimal dose application of LLLT.

      After defining the best dose of application, we recruited two groups which will be irradiated
      with different power, 100mW and 400mW in order to seek the optimal parameter of low level
      laser therapy in performance.

      The investigators believed that the Low Level Laser Therapy can delay the physiological
      process of muscle fatigue, reduce injury or skeletal muscle microdamage arising from physical
      effort and accelerate muscle recovery after exercise.
    

Detailed description: 
      To achieve the proposed objectives it was performed a randomized, double-blinded,
      placebo-controlled trial, with voluntary participation of high-level soccer athletes.

      Participants received an application of low level laser prior to execution of a strenuous
      exercise. It was used a laser with a cluster of 5 diodes (810 nm, 200 mW each diode) with
      different doses (placebo, 2J, 6J, 10J) and power of 200mW.

      In a second step, with the optimal dose already defined, this was used to be applied with
      different powers in two experimental groups, 100mW and 400mW.

      The investigators analysed parameters related to volunteers exercise performance (torque peak
      / maximum voluntary contraction), delayed onset muscle soreness, and biochemical markers of
      muscle damage (CK and LDH), inflammation (interleukin 1 and 6, alpha tumoral necrosis factor)
      and oxidative stress (TBARS, CAT, SOD and carbonylated proteins). The analysis was performed
      before exercise protocols, after 1 minute, and 1, 24, 48, 72 and 96 hours after the end of
      exercise protocol in both parts of the study.
    

Intervention name(s): Low Level Laser (LLL)
Intervention type(s): Device
Intervention description(s): Comparison of different dosages of a Low Level Laser applied in six different locations of the knee extensor muscles of the lower limb non-dominant before a strenuous exercise.
We performed stretching and warming up of the muscles involved, assessment of muscle pain, withdrawal of blood sample, test muscle function (MVC), application of dose of low level laser designated for each volunteer (0, 2, 6 or 10), performing eccentric contractions protocol in isokinetic dynamometer . After the protocol we evaluated muscle function, the DOMS, and blood analyzes in 1 minute, 1 hour, 24 hours, 48 hours 72 hours and 96 hours.
In a second stage, the optimal dose defined by the first part of the study will be tested in two different powers, 100 and 400mW. The study was repeated in two experimental groups using the optimal dose established and the powers of 100 and 400mW that was randomly distributed in groups.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: LLLT; muscle fatigue and recovery; phototherapy parameter