Chiropractic + Naturopathic Doctor

Laser-focus: PMB therapy for rehab and improvement of muscle function

By Dr. Don Fitz-Ritson, DC   

Features Patient Care Techniques athletic therapy fitness laser therapy muscle rehabilitation

I began using lasers in 1984. In fact, I was the pioneer using lasers in the chiropractic profession. My interest initially piqued because I had been suffering with chronic pain for a year (the result of three motor vehicle accidents I sustained by being rear ended while stopped at traffic lights), and no therapy seemed to help the condition. In 1983, I met a scientist, Dr. Stalansky, who introduced me to lasers. Using specific protocols, I had no headaches and minimal neck pain after 18 treatments. When it came to treating my low back with the specific protocols for that area, after 12 treatments, my back pain was 80 percent better. Under Dr. Stalansky’s tutelage, I dived into understanding the mechanisms of how laser affected my chronic pain. Later, an engineer and I co-invented a laser, which received seven Health Canada approvals.

Two of the main things that Laser/Photobiomodulation – PBM therapy (new name) does is increase ATP production in tissue, which promotes tissue healing and decreases pain and inflammation. These are very powerful effects to use with chiropractic treatments. Over the years, the combination of chiropractic and PBM therapy has provided my patients with effective therapy and satisfaction for myself – after all, I am using natural therapies to achieve effective, time-targeted results. To obtain good results with PBM Therapy, one has to understand the principles by which it operates. These include power density, wavelength, Joules, red light and infrared light, to name a few. 

Think for a minute, you are about to manipulate an inflamed joint in your patients neck. Think about the motor unit, all the tonic muscles holding the joints and limiting their movements. The manual therapy will begin to align the joints, but what about the muscles that need healing, restoring their function and the inflammation in the joints?


Overview of Photobiomodulation(PBM therapy)
Recently a consensus decision was taken to use the terminology “PBM” since the term “low-level lasers” was very subjective, and it is now known that actual lasers are not required, as non-coherent light-emitting diodes (LEDs) work equally well. For a long time, the mechanism of action of PBM was unclear, but in recent years much progress has been made. Many wavelengths in the red (600–700 nm) and near-infrared (NIR, 770–1200 nm) spectral regions have shown positive results. However there is a region in between (700–770 nm) where, broadly speaking, the results are likely to be disappointing.

It is accepted that penetration of light into tissue is governed by both absorption and scattering by molecules and structures present in the tissue. Both absorption and scattering become significantly less as the wavelength gets longer, so the penetration depth of NIR is maximal at about 810 nm, and at longer wavelengths water becomes an important absorber and penetration depth gets shorter again.

The “biphasic dose response” describes a situation in which there is an optimum value of the “dose” of PBM most often defined by the energy density (J/cm2). It has been consistently found that when the dose of PBM therapy is increased, a maximum response is reached at some value, and if the dose is increased beyond that maximal value, the response diminishes, disappears and it is even possible that negative or inhibitory effects are produced at very high fluences. Also one has to be aware of the physiology of the tissue been treated. Cells/tissues with high numbers of mitochondria tended to respond to lower doses of light compared to cells/tissues with lower number of mitochondria.(1)

The effect on the cell’s mitochondria is striking. The primary chromophores have been identified as cytochrome c oxidase in mitochondria, and calcium ion channels (possibly mediated by light absorption by opsins). Secondary effects of photon absorption include increases in ATP, a brief burst of reactive oxygen species, an increase in nitric oxide, and modulation of calcium levels. Tertiary effects include activation of a wide range of transcription factors leading to improved cell survival, increased proliferation, migration and new protein synthesis and angiogenesis.(2)

The above insights will inform one on how to use PBM therapy (PBMt) for pain relief and to reduce inflammation, enhance healing of tissue repair and improve function. The application of these properties has been employed and observed in the treatment of various diseases and conditions, such as diabetes, brain injury, spinal cord damage, dermatological conditions, oral irritation, and in different areas of dentistry.(3) For example, for neuropathic pain, a combination of initial high irradiance/fluence rates for fast pain relief, followed by a series of low irradiance/fluence rates for prolonged pain relief, will alter the chronic inflammation residues.(4)

Target areas for muscle performance
Outlined are areas where one can apply PBM therapy and improve muscle performance. Muscles are designed for and cause movement and movement begins in the brain. Traumatic brain injury has been shown to respond to PBM therapy. PBMt helps the brain repair itself by stimulating neurogenesis, upregulating BDNF synthesis, and encouraging synaptogenesis. PBMt increases regional cerebral blood flow, tissue oxygenation, and improves memory, mood, and cognitive function. There is also improvement with executive function, working memory, and sleep.(5) If one were to use PBMt on the brain area for say the quads, would this initiate the process of improving the quads function? A recent study showed that by stimulating the hand area of the motor cortex with PBMt, finger taps increased in both hands as an indicator of motor performance improvement.(6) This may work for the quads too.

 Spinal cord and peripheral nerves respond effectively to PBMt. PBMt decreases inflammation in spinal cord injury.(7) As well, PBMt accelerates the axonal cell growth by increasing their function via biochemical activity and improves morphological recovery in atrophied muscle.(8) Combining PBMt and Chiropractic therapy, we now have ways to improve spinal cord, peripheral nerves and muscle atrophy. Many patients with rhomboid and gastrocnemius atrophy have responded effectively with this combination in my practice.

The intervertebral disc (IVD) is constantly under wear and tear, and low grade inflammation may develop. This low grade inflammation can exert pressure on the spinal cord and nerves, affecting innervation patterns and nutrient flow to muscles. The annulus fibrosus (AF) cells, are the first line of defense in preventing inflammation in the IVD. PBMt, using different wavelengths and doses, selectively inhibites the production of inflammatory mediators, catabolic enzymes, and neurotrophins by human AF cells in a dose- and wavelength-dependent manner. This study results suggest that PBMt could be a superior and advanced treatment strategy for IVD degeneration.(9) The nucleus pulposus (NP) cells of the IVD, also responds to different doses and wavelengths of PBMt regarding inflammation. However, there is a specific wavelength which also modulated the protein and gene expression of IL-8, which is responsible for the anabolic response in human NP cells. The findings suggeste that PBMt, at an optimal dose and wavelength, is a useful therapeutic tool to treat IVD degeneration.(10) Understanding the above and appreciating that PBMt modulates prostaglandin E2 levels, indicates that these may be the mechanisms involved in the analgesic effects of PBMt in patients with LBP.(11)

Muscle injury
Muscle tissue are injured from time to time through various activities. Repair of muscle tissue is very complex, but is defined by very specific steps. Macrophages play an important role in the regenerative processes due to their plasticity and multiple functions. In the muscle repair process, while M1 macrophages regulate the inflammatory and proliferative phases, M2 (anti-inflammatory) macrophages direct the differentiation and remodelling phases, leading to tissue regeneration. Both PBMt of red and NIR wavelengths positively affect M1 and M2 macrophages. However, only NIR wavelength is able to increase the number of M2 and mRNA, allowing the repair process to rapidly express itself. Treatment with PBMt, using NIR wavelength is able to modulate the inflammation phase, optimize the transition from the inflammatory to the regeneration phase, and improve the final step of regeneration, enhancing tissue repair.(12). Specific exercise protocols can also help to stimulate the regenerative process and assist with tissue repair.(13). Interestingly, exercise for tissue repair can cause low grade fibrous/scar formation. In acute injuries, with early intervention with PBMt, fibrous/scar formation does not occur. However, in my practice we have had cases with fibrous/scar in the chronic injured area, using PBMt on the area reduced the fibrous/scar tissue, decreased the pain and increased the range of movement. 

Muscle performance
Muscles seem to love PBMt because they have a high density of mitochondria and muscles respond significantly to PBMt application. PBMt can increase muscle performance when applied before training, increase the effectiveness of training and decrease the after effects of training. Not to mention that PBMt can also alleviate pain, soreness and heal micro injuries due to training. Because of its efficacy and performance enhancing effect, researchers have even raised concerns regarding whether it should be allowed at Olympic competition.

 In a systematic review with meta-analysis the researchers concluded that PBMt with red and NIR wavelengths improves muscular performance and accelerates recovery mainly when applied before exercise.(14) These results were not limited to athletes, because PBMt in combination with strength training was also able to improve muscle performance in elderly people.(15) PBMt using 904 nm wavelength was effective in reducing fatigue levels and increasing muscle performance in young active women.(16) In another systemic review with meta-analysis, PBMt and exercise caused the improvement of muscular performance and reduction of muscular fatigue in healthy people.(17). When red, NIR, and red/NIR mixtures were used,  PBMt caused increased muscle mass gained after training, and decreased inflammation and oxidative stress in muscle biopsies. The researchers raised the question of whether PBMt should be permitted in athletic competition by international regulatory authorities.(18). This is a valid question, because this study showed that PBMt applied for 12 weeks before and after endurance-training exercise sessions lead to improvement of endurance three times faster than exercise only.(19). Can you imagine the results if they had added nutrition and supplements, because these have also been shown to improve muscle health and strength?

The future is very promising for PBMt, whether it focuses on treatment/rehab, a therapy for human performance, or a combination of both. Due to its efficacy, its scope of applications continues to expand into neuromuscular skeletal and osteoarthritis(20),(21), traumatic brain injury and stroke(5), Parkinson’s Disease(22) and depression(23), to name a few. New therapeutic approaches are also developing, such as using multiple wavelengths to treat different layers of tissue at the same time for more comprehensive results.(24).What is required to help PBMt reach its’ full potential is an Institute for researching all the parameters and defining specific protocols for each condition. This will assist with standardizing for research and treatment purposes, which will help to advance PBMt as an evidence based alternate health care choice.


  1. Zein R, et al. Review of light parameters and photobiomodulation efficacy: dive into complexity. J Biomed Opt. 2018 Dec; 23(12): 1-17.
  2. Hamblin M. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337-361.
  3. Dompe C, et al.  Photobiomodulation-Underlying Mechanism and Clinical Applications. J Clin Med. 2020 Jun 3; 9(6): 1724. 
  4. Holanda V, et al. The mechanistic basis for photobiomodulation therapy of neuropathic pain by near infrared laser light. Lasers Surg Med. 2017 Jul; 49(5): 516-524.
  5. Hamblin M. Photobiomodulation for traumatic brain injury and stroke. J Neurosci Res. 2018 Apr; 96(4): 731-743.
  6. Fekri A, et al. Short-term Effects of Transcranial Near-Infrared Photobiomodulation on Motor Performance in Healthy Human Subjects: An Experimental SingleBlind Randomized Clinical Trial. J Lasers Med Sci. Fall 2019;10(4):317-323.
  7. Li K, et al. Attenuation of the inflammatory response and polarization of macrophages by photobiomodulation. Lasers Med Sci. 2020 Sep;35(7):1509-1518.
  8. Rochkind S. Photobiomodulation in Neuroscience: A Summary of Personal Experience. Photomed Laser Surg. 2017 Nov;35(11):604-615. 
  9. Hwang M, et al. Effects of photobiomodulation on annulus fibrosus cells derived from degenerative disc disease patients exposed to microvascular endothelial cells conditioned medium. Sci Rep. 2020 Jun 15; 10(1): 9655. 
  10. Hwang M, et al. Phototherapy suppresses inflammation in human nucleus pulposus cells for intervertebral disc degeneration. Lasers Med Sci. 2018 Jul; 33(5): 1055-1064. 
  11. Tomazoni S, et al.  Photobiomodulation Therapy is Able to Modulate PGE 2 Levels in Patients With Chronic Non-Specific Low Back Pain: A Randomized Placebo-Controlled Trial. Lasers Surg Med. 2020 Apr 24. 
  12. Souza N, et al. Photobiomodulation and different macrophages phenotypes during muscle tissue repair. J Cell Mol Med. 2018 Oct;22(10):4922-4934. 
  13. Perandini L, et al. Chronic inflammation in skeletal muscle impairs satellite cells function during  regeneration: can physical exercise restore the satellite cell niche? FEBS J. 2018 Jun;285(11):1973-1984. 
  14. Leal-Junior E, et al. Effect of phototherapy (low-level laser therapy and light-emitting diode therapy) on exercise performance and markers of exercise recovery: a systematic review with meta-analysis. Lasers Med Sci. 2015 Feb; 30(2): 925-39. 
  15. Toma R, et al. Low level laser therapy associated with a strength training program on muscle performance in elderly women: a randomized double blind control study. Lasers Med Sci. 2016 Aug;31(6):1219-29. 
  16. Toma R, et al. Photobiomodulation (PBM) therapy at 904 nm mitigates effects of exercise-induced skeletal muscle fatigue in young women. Lasers Med Sci. 2018 Aug;33(6):1197-1205. 
  17. Vanin A, et al. Photobiomodulation therapy for the improvement of muscular performance and reduction of muscular fatigue associated with exercise in healthy people: a systematic review and meta-analysis. Lasers Med Sci. 2018 Jan;33(1):181-214. 
  18. Ferraresi C, et al. Photobiomodulation in human muscle tissue: an advantage in sports performance? J Biophotonics. 2016 Dec; 9(11-12): 1273-1299. 
  19. Miranda E, et al. When is the best moment to apply photobiomodulation therapy (PBMT) when associated to a treadmill endurance-training program? A randomized, triple-blinded, placebo-controlled clinical trial. Lasers Med Sci. 2018 May; 33(4): 719-727. 
  20. Gendron D, et al. Applications of Photobiomodulation Therapy to Musculoskeletal Disorders and Osteoarthritis with Particular Relevance to Canada. Photobiomodul Photomed Laser Surg. 2019 Jul; 37(7): 408-420. 
  21. Gomes C, et al. Incorporation of photobiomodulation therapy into a therapeutic exercise program for knee osteoarthritis: A placebo-controlled, randomized, clinical trial. Lasers Surg Med. 2018 Oct; 50(8): 819-828. 
  22. Foo A, et al. Mitochondrial Dysfunction and Parkinson’s Disease-Near-Infrared Photobiomodulation as a Potential Therapeutic Strategy. Front Aging Neurosci. 2020 Apr 3; 12: 89. 
  23. Caldieraro M, et al. Transcranial and systemic photobiomodulation for major depressive disorder: A systematic review of efficacy, tolerability and biological mechanisms. J Affect Disord. 2019 Jan 15;243:262-273. 
  24. Lima A, et al.  Photobiomodulation via multiple-wavelength radiations. Lasers Med Sci. 2020 Mar;35(2):307-316.

Dr. Don Fitz- Ritson is a chiropractor and a rehab specialist. He was an Assistant Professor at CMCC. He published 17 papers and 3 chapters on chiropractic.He co-invented a laser and it received 7 Health Canada Approvals. He is focused on helping the aging population live better lives.

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