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Laser Therapy

Laser therapy or phototherapy is the latest therapy under the spotlight for its potential to enhance recovery, prevent injuries and improve performance. Laser therapy adds to the growing list of interventions designed to enhance recovery, such as massage, low-intensity exercises, cryotherapy, hot-cold contrast baths, neuro-muscular electrical stimulation, and stretching to name a few. Each of these intervention aims in one way or another to reduce post-exercise inflammation and promote circulation and metabolism to help drain fluids and metabolites.

What is Laser Therapy?

In scientific circles, laser therapy is more commonly referred to as phototherapy. In its most basic sense, phototherapy involves the application of light (either a low power laser or LED) to a pathology. As such, phototherapy is sometimes classified into two types, namely, low-level laser therapy (LLLT) and light emitting diode therapy (LEDT). LLLT involves the application of light using a single diode laser, while LEDT involves the application of light via a multi-diode cluster probe1. However, LLLT is the general term that is often used to collectively refer to both types of laser therapy.

How Does Laser Therapy Work

The light used during phototherapy is typically of narrow spectral width, which is defined as red or near infrared (NIR) spectrum (i.e., 600nm – 1000nm) and has a power density (also referred to as irradiance) between 1mw-5W/cm2. It is typically applied to the injury/muscle for a minute or so, a few times a week for several weeks. Unlike other medical laser procedures, LLLT does not work via an ablative or thermal mechanism, but rather by a photochemical mechanism; comparable to photosynthesis in plants, whereby the light is absorbed and exerts a chemical change.

Parameters in Laser Therapy

Phototherapy involves a number of parameters, which can be adjusted based on the type of treatment. Much of the current research is focused on determining the best combination of variables for a given application such as muscle pain or muscle performance enhancement. The parameters in question are listed in the table below.






Red (600-750nm) Infrared (850-1000nm)

Power/Optical output


Typically below 200mW

Spot or laser size


Self explanatory

No. of lasers/diodes


Laser units/heads may have multiple laser diodes within the one unit

Power density


Self explanatory

Energy density


Self explanatory



Total of energy from each laser spot

Treatment time


Product of treatment time for each point  and number of points

Number of irradiation points per muscle



Total energy delivered per muscle


Product of irradiation points per muscle & energy from each laser spot


What Is Laser Therapy Used For?

LLLT has traditionally been used to treat muscle/joint pain and injury. You might be surprised to learn that LLLT has been around for some time, with the first clinical trial published way back in 198013. Since then many studies have been published showing LLLT is an effective treatment for a range of pathologies including osteoarthritis14, tendinopathies15, 16, wounds17,18, back pain19, neck pain20-22, peripheral nerve injuries23 and strokes24. In fact the evidence supporting the use of LLLT for popular chronic issues such as neck pain is now so overwhelming, that positive reviews have appeared in one of the most prestigious medical journal, namely, The Lancet31.

Can Laser Therapy Improve Exercise Performance?

But possibly the most exciting application of LLLT that has received a lot of focus in recent years is its potential to improve exercise performance and enhance recovery in athletes. In animal models, LLLT using both red and infrared wavelengths has been shown to reduce muscle fatigue symptoms2, 3.  While in human studies, although a small pilot study with only 5 subjects4 reported no benefits, there is solid evidence that phototherapy can decrease muscle fatigue when applied before free weight1, 5-7, isokinetic8 and running9 exercises.

Some of the more recent studies on phototherapy have measured its specific ability to improve high intensity exercise performance. These studies have shown phototherapy can reduce biochemical markers of skeletal muscle fatigue when applied prior to high intensity exercise10, 11 as well as decrease post-exercise markers of muscle damage and lactate12. However, interestingly, a number of these studies did not report performance improvements despite the improved biochemical measures of fatigue and muscle damage. So there’s still a bit of debate as to whether LLLT is a more effective tool for performance enhancement or recovery. One of the factors that may explain these contrasting results is the use of different laser treatment parameters across studies.

Effect of Red vs Infrared LLLT on Muscle Fatigue

In an attempt to resolve the effects of different laser wavelengths, a recent study compared the effect of red (660 nm) versus infrared (830 nm) LLLT on skeletal muscle fatigue in humans. To the author’s surprise, there was no significant difference between the two, but both served to delay the development of muscle fatigue and enhance muscle performance25.

How Does Laser Therapy Work?

The above study highlights that scientists have yet to uncover the exact mechanisms by which different types of laser therapy work. However, significant progress has been made in recent years concerning some of the fundamental mechanisms by which laser therapy works. This research shows that across a range of different pathologies, LLLT works to increase microcirculation26, enhance ATP synthesis and stimulate mitochondrial respiration27 and function 28. Reductions in the release of reactive oxygen species (ROS) and in creatine phosphokinase activity and increased production of antioxidants and heat shock proteins have also been found after LLLT29, 30.

Prospects of Laser Therapy

In closing it has to be said that LLLT is an exciting therapy for a range of musculoskeletal conditions and despite common misconceptions, it has a wealth of credible research to support its efficacy and mechanism of action. Many recent studies have focused on LLLT’s ability to enhance muscular performance and recovery, with some very encouraging results. As such, LLLT is set to become an increasingly popular tool for use by sporting teams and competitive athletes. With effectively no side-effects, it’s certainly something worth trying if you have a persistent injury or are just looking for something new to give you that extra edge!

1. Leal-Junior EC, et al. Effect of cluster multi-diode light emitting diode therapy (LEDT) on exercise-induced skeletal muscle fatigue and skeletal muscle recovery in humans. Lasers in Surgery and Medicine. 2009;41:572-577.

2. Leal-Junior EC, et al. Effect of low-level laser therapy (GaAs 904 nm) in skeletal muscle fatigue and biochemical markers of muscle damage in rats. European Journal of Applied Physiology. 2010;108:1083-1088.
3. Lopes-Martins RA, et al. Effect of low-level laser (Ga-Al-As 655 nm) on skeletal muscle fatigue induced by electrical stimulation in rats. Journal of Applied Physiology. 2006;101:283-288.
4. Gorgey AS, et al. The effect of low-level laser therapy on electrically induced muscle fatigue: a pilot study. Photomedicine and Laser Surgery. 2008;26:501-506.

5. Leal-Junior EC, et al. Effect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans. Photomedicine and Laser Surgery. 2008;26:419-424.

6. Leal-Junior EC, et al. Effects of Low-Level Laser Therapy (LLLT) in the development of exercise-induced skeletal muscle fatigue and changes in biochemical markers related to post-exercise recovery. Journal of Orthopaedic & Sports Physical Therapy. 2010;40:524e532.

7. Leal-Junior EC, et al. Effect of 830 nm low-level laser therapy in exercise-induced skeletal muscle fatigue in humans. Lasers in Medical Science. 2009;24:425-431.

8. Baroni BM, et al. Effect of light-emitting diodes therapy (LEDT) on knee extensor muscle fatigue. Photomedicine and Laser Surgery. 2010;28:653-658.

9. De Marchi T, et al. Low-level laser therapy (LLLT) in human progressive intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress. Lasers in Medical Science. 2012;27: 231-236.
10. Leal-Junior EC, et al. Comparison between single-diode low level laser therapy (LLLT) and LED multi-diode (cluster) therapy (LEDT) applications before high-intensity exercise. Photomedicine and Laser Surgery. 2009;27:617-623.
11. Leal-Junior EC, et al. Effect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans. Photomedicine and Laser Surgery. 2008;26:419-424.
12. Leal-Junior EC, et al. Effect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in athletes. Lasers in Medical Science. 2009;24: 857-863.
13. Goldman JA, et al. Laser therapy of rheumatoid arthritis. Lasers Surg Med. 1980;1:93–101.

14. Hegedus B, et al. The effect of low-level laser in knee osteoarthritis: a double-blind, randomized,placebo-controlled trial. Photomed Laser Surg. 2009;27:577–584.

15. Bjordal JM, .A randomised, placebo controlled trial of low level laser therapy for activated achilles tendinitis with microdialysis measurement of peritendinous prostaglandin E2 concentrations. Br J Sports Med. 2006;40:76–80.
16. Stergioulas A, et al. Effects of low-level laser therapy and eccentric exercises in the treatment of recreational athletes with chronic achilles tendinopathy. Am J Sports Med. 2008;36:881–887.
17. Ozcelik O, et al. Improved wound healing by low-level laser irradiation after gingivectomy operations: a controlled clinical pilot study. J Clin Periodontol. 2008;35:250–254.

18. Schubert MM, et al. A phase III randomized double-blind placebo-controlled clinical trial to determine the efficacy of low level laser therapy for the prevention of oral mucositis in patients undergoing hematopoietic cell transplantation. Support Care Cancer. 2007;15:1145–1154.
19. Basford JR, et al. Laser therapy: a randomized, controlled trial of the effects of low-intensity Nd: YAG laser irradiation on musculoskeletal back pain. Arch Phys Med Rehabil. 1999;80:647–652.
20. Gur A, et al. Efficacy of 904 nm gallium arsenide low level laser therapy in the management of chronic myofascial pain in the neck: a double-blind and randomize-controlled trial. Lasers Surg Med. 2004;35:229–235.
21. Chow RT, et al. The effect of 300 mW, 830 nm laser on chronic neck pain: a double-blind, randomized, placebo-controlled study. Pain. 2006;124:201–210.
22. Chow RT, et al. Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. Lancet. 2009;374:1897–1908.

23. Rochkind S, et al. Efficacy of 780-nm laser phototherapy on peripheral nerve regeneration after neurotube reconstruction procedure (double-blind randomized study). Photomed Laser Surg. 2007;25:137–143.

24. Lampl Y, et al. Infrared laser therapy for ischemic stroke: a new treatment strategy: results of the NeuroThera Effectiveness and Safety Trial-1 (NEST-1). Stroke. 2007;38:1843–1849.
25. de Almeida P, et al. Red (660 nm) and infrared (830 nm) low-level laser therapy in skeletal muscle fatigue in humans: what is better? Lasers Med Sci. 2012;27(2):453-458.
26. Tullberg M, et al. Effects of low power laser exposure on masseter muscle pain and microcirculation. Pain. 2003;105:89–96.

27. Silveira PC, et al. Evaluation of mitochondrial respiratory chain activity in muscle healing by low-level laser therapy. J Photochem Photobiol B. 2009;95:89–92.

28. Xu X, et al. Low-intensity laser irradiation improves the mitochondrial dysfunction of C2C12 induced by electrical stimulation. Photomed Laser Surg. 2008;26:197–202.

29. Avni D, et al. Protection of skeletal muscles from ischemic injury: low-level laser therapy increases antioxidant activity. Photomed Laser Surg. 2005;23:273–277.
30. Rizzi CF, et al. Effects of low-level laser therapy (LLLT) on the nuclear factor (NF)-kappaB signaling pathway in traumatized muscle. Lasers Surg Med. 2006;38:704–713.
31. Chow RT, et al. Efficacy of low-level laser therapy in the management of neck pain: a systematic review and meta-analysis of randomised placebo or active-treatment controlled trials. Lancet. 2009;374:1897–908.

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