LED Therapy: 30% Increase in Max. # of Reps in New Study, Increased Stamina and More Recent LLLT / LEDT Data

The scientists used an LEDT device from Thor on two points on the distal portion of the vastus lateralis, two points on the distal portion of the vastus medialis and two centered points along the rectus femoris (see Figure 1, right).

It may be partly my fault that most of you ask me for supplements to take to increase their performance and do not expect often not even consider the possibility of being told about technological items like a low-level laser diode device to up their gains or boost their fat loss...

When I started this blog a few years ago, I was guilty of believing that supplements would be the most relevant ergogenics for anyone who trains, myself. Today, ~2,300 articles later, this has changed: don't get me wrong - supplements can be useful, but diet, training and - at least in a few cases - even things like using light emitting diode therapy (LEDT) or low-level laser therapy (LLLT), as it is also called, are much higher on the "things that really work"-list.

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In that, it is important to point out that a recent study from the Georgia Southern University (Hemmings. 2016) is neither the first study to show significant performance / recovery benefits from LEDT, nor is it the first study I wrote about (read previous articles). The experiment Hemmings et al. conducted is yet the first to evaluate the effects of different dosages of LEDT (30 vs. 60 vs. 120 seconds on each irradiation point, see Figure 1, right) that was applied by the means of a low-level laser (THOR, London, UK) on muscular fatigue of the quadriceps after two sets of three maximal voluntary isometric contractions (MVIC).

Figure 1: Comparison of repetitions and blood lactate concentrations between all four trials; illustration of the irradiation points that were used for LEDT (Hemmings. 2016)

A total of 34 recreationally resistance trained athletes between the ages of 18 and 26 participated in four trials. Each trial included pre/post exercise blood lactate measurements, the previously hinted at MVIC and a single set of eccentric leg extensions (at 120% of the previously determined MVC) to exhaustion that was done three minutes after the initial exercises and used as a yard-stick for the recovery benefits of using 30s, 60s and 120s of LEDT compared to a 45s placebo treatment of which the subjects thought that it was yet another irradiation time that was to be tested.

LLLT therapy has also been shown to almost double the muscle gains in a study with an 8-week eccentric training program | more

LLLT and LEDT - What does the science say?: Here's how the authors explain the difference, between different forms of laser light therapy (LLT) and light emitting diode therapy (LEDT): "The difference between LLT and LEDT is the power output and depth of penetration due to various patterns in wavelengths" (Hemmings. 2016). The potential mechanism, on the other hand is always the same: "[r]esearch suggests that LLLT can prolong the binding of nitric oxide to the cytochrome C oxidase enzyme, which permits the muscle to produce more ATP in the preferred oxidative pathway" (Hemmings. 2016).

A recent meta-analysis (Nampo. 2016) evaluated both, the effects of LLLT and LEDT, on exercise capacity and muscle performance of people undergoing exercise when compared to placebo treatment. Sixteen studies involving 297 participants were included in the meta-analysis that shows a mean improvement of the number of repetitions of 3.51 reps (0.65–6.37; P = 0.02), a 4,01 second delay in time to exhaustion (2.10–5.91; P < 0.0001), and - unlike the study at hand - a sign. reduction in lactate levels (MD = 0.34 mmol/L [0.19–0.48]; P < 0.00001) and increased peak torque (MD = 21.51 Nm [10.01–33.01]; P < 0.00001).

Exercise capacity - Number of reps (left), time to exhaustion (right | Nampo. 2016)

Reason enough for the authors to conclude that their "results suggest that LASERtherapy is effective in improving skeletal muscle exercise capacity" - one thing Nampo et al. rightly add is that "the quality of the current evidence is limited" (Nampo. 2016).

As you would expect it for any effective ergogenic, the scientists observed a "significant increase in the number of repetitions performed between the placebo treatment" (Hemmings. 2016). In that, it is interesting to see that both treatments, i.e. 60 seconds (p= 0.023), as well as the 120 seconds (p=0.004) LEDT treatment triggered a significant increase in the number of reps the subjects completed - without, however, significantly affecting the accumulation of blood lactate levels in the subjects' blood. Another thing the data in Figure 1 tells us that must not be forgotten is the lack of effect of applying LEDT for only 30 seconds per irradiation point (see Figure 1, right).

Lactate is not the enemy - remember? Caffeine and Bicarbonate (NaHCO3), two proven ergogenics increase, not decrease blood lactate accumulation while still boosting subjects' performance during a standardized yo-yo performance test | learn more.

While the last-mentioned lack of effect of a shorter treatment is probably something you'd expect, the lack of effect on the accumulation of lactate may come as a surprise. Eventually, however, the exercise duration was probably simply too short to accumulate exuberant lactate levels. It is imho also questionable why the scientists used lactate, not CK or another potential measure of muscle damage (or a biopsy) to judge the effects of the LEDT treatment on a molecular level. After all, the often-heard hypothesis that the accumulation of lactate would be the reason you fail due to muscular exhaustion is - in view of the existing evidence - at least questionable.

What about gains and does timing matter? No, you don't have to be afraid that LLLT would have the same negative effects on your gains as ice-baths. It has, after all, already been shown to double the gains in a 2015 8-week study in healthy volunteers | read more! And the timing, yeah... Well, yes timing does matter! You have to apply it before the workout to see effects... at least for immediate 1RM strength gains this is the case according to a very recent study by Vanin (2016) - future studies will tell if using it post, as a recovery tool can be effective in the long-term.

As a SuppVersity reader you will, for example, remember that proven ergogenics such as bicarbonate and beta alanine increase the accumulation of lactate significantly... ok, you may argue that they simply protect the muscle from the tiring effects of lactate, but eventually there are other more likely candidates to explain the onset of fatigue such as the accumulation of other muscle metabolite, a decrease in free energy of adenosine triphosphate, limited O2 or other substrate availability, increased glycolysis, pH disturbance, increased muscle temperature, reactive oxygen species production, and altered motor unit recruitment patterns (Grassi. 2015; Poole. 2015), which could eventually explain why our muscles fatigue and why the lactate levels increase (reduced ATP, for example, will necessarily increase glycolysis and eventually the lactate accumulation).

This is only one of of several LLLT studies I've discussed in detail in older SV articles. Examples? What about this one from Aug 2015: Phototherapy Doubles Fat Loss (11 vs. 6%) & Improvements in Insulin Sensitivity (40 vs. 22%) and Helps Conserve Lean Mass in Recent 20 Weeks 'Exercise for Weight Loss Trial' | read more

Bottom line: Yeah, the scienists are right to conclude that "light emitting diode therapy had a positive effect on performance when irradiating six points on the superficial quadriceps for 60 seconds and 120 seconds prior to an eccentric leg extension" (Hemmings. 2016).

What can be refuted based on their results, however, is that this effect was a consequence of reduced lactate levels. That's in contrast to another recent study in a particularly vurnerable subgroup of hobby athletes, i.e. the hospitalized patients with heart failure in a pilot study by Bublitz et al. who found a significant decrease in lactate accumulation, albeit in response to a 6-minute walking exercise, during which LLDT was able to reduce the subjective fatigue and the previously discussed lactate concentrations, but not the subjects' performance.

Overall, it seems reasonable to conclude that further research is necessary to (a) elucidate the underlying mechanism behind the (pro-)recovery / performance enhancing effects, as well as LEDT's / LLLT's previously reported beneficial effects on insulin sensitivity and body composition and the most promising areas of application (according to the study at hand this could be resistance training / any sport that requires maximal anaerobic performance) | Comment!

References:

• Bublitz, Caroline, et al. "Acute effects of low-level laser therapy irradiation on blood lactate and muscle fatigue perception in hospitalized patients with heart failure—a pilot study." Lasers in medical science (2016): 1-7.
• Byrne, Christopher, Craig Twist, and Roger Eston. "Neuromuscular function after exercise-induced muscle damage." Sports medicine 34.1 (2004): 49-69.
• Grassi, Bruno, Harry B. Rossiter, and Jerzy A. Zoladz. "Skeletal muscle fatigue and decreased efficiency: two sides of the same coin?." Exercise and sport sciences reviews 43.2 (2015): 75-83.
• Hemmings, Thomas J. "Identifying Dosage Effect of LEDT on Muscular Fatigue in Quadriceps." Journal of Strength and Conditioning Research (2016): Publish Ahead of PrintDOI: 10.1519/JSC.0000000000001523..
• Poole, David C., and Thomas J. Barstow. "The critical power framework provides novel insights into fatigue mechanisms." Exercise and sport sciences reviews 43.2 (2015): 65-66.
• Vanin, Adriane Aver, et al. "What is the best moment to apply phototherapy when associated to a strength training program? A randomized, double-blinded, placebo-controlled trial." Lasers in Medical Science (2016): 1-10.

Phototherapy Doubles Fat Loss (11 vs. 6%) & Improvements in Insulin Sensitivity (40 vs. 22%) and Helps Conserve Lean Mass in Recent 20 Weeks 'Exercise for Weight Loss Trial'

LLLT has also been shown to improve the appearance of cellulite (Jackson. 2013) | Learn more about what really helps against cellulite in this SV Classic

You know that I am not a fan of isolated "exercise / supplement for weight loss trials", but there's one thing I like about them. When the diet is not controlled for and the subjects still lose weight, it is very likely that the intervention is going to work in the real-world, as well. And if the exercise protocol is both manageable and useful, as it was the case in a recent study from the University of Sao Paulo (Sene-Fiorese. 2015), this makes me even more inclined to actually write about the study, even though it may be - from a mere scientific perspective - not provide "bulletproof" evidence of what's the exact cause of the effects, the exercise or supplement, it's effect on energy intake or both.

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But let's return to the study at hand: Manageable and useful, in this case, meant three exercise sessions per week with 30 minutes of aerobic training and 30 minutes of resistance training per session.

"During the intervention period, the voluntaries [sic!] followed a combined exercise training therapy. The protocol was performed three times per week and included 30 minutes of aerobic training and 30 minutes of resistance training per session. The aerobic training consisted of running on a motor-driven treadmill (Movement®) between 70 and 85% of maximal heart frequency, which was determined previously by treadmill submaximal test. The resistance exercise training was composed using exercises for the main muscular groups: bench press, leg press, sit-ups, lat pull-down, hamstring curls, calf raises, Straight-Bar Cable Curl (biceps), triceps pushdown, adductor and abductor chairs [see Table 1]. Training loads were successively adjusted, with volume and intensity being inversely modified and the number of repetitions being decreased to between 6 and 20 repetitions for three sets. The training loads were adjusted in each training session and evaluated according to the increase in participants’ strength. Thus, the training was conducted with maximal repetitions (RM)" (Sene-Fiorese. 2015).

For the study, the scientists recruited a total of 64 adult obese women via classic newspapers and magazines as well as electronic media, TV and radio. The inclusion criteria were (i) primary obesity, body mass index (BMI) between 30 and 40 kg/m², (ii) age between 20 and 40 years old. Exclusion criteria were (i) the use of cortisone, anti-epileptic drugs; (ii) history of renal disease; (iii) alcohol intake; (iv) smoking; and (v) secondary obesity due to endocrine disorders. The inclusion and exclusion criteria were assessed by clinical evaluation by physician (endocrinologist).

Table 1: The scientists a resistance training protocol that had previously been used in Foschini (2010)

While the treatment consisted of physical exercise intervention and the individual application of phototherapy immediately after the end of the exercise training session for all volunteers. The scientists randomly assigned the subjects to an active ET-PHOTO and a "SHAM" control group ET-SHAM.

This is a placebo controlled study! I think it's worth highlighting the fact that both groups believed they'd received the treatment, because all subjects had to go to the phototherapy sessions, but the device was actually turned on only for those in the ET-PHOTO, not for those in the ET-SHAM group.

In the ET-SHAM group the device which emits light at a wavelength that's too long for the human eye to actually see it was turned off. Thus the subjects in the SHAM = control group received a simulated phototherapy application ... and yes, that's basically the same thing as the "placebo group" in your average supplement study..

Figure 1: Photo of the Device, Illustration of the Area of Application; Device Information, Irradiation and Treatment Parameters (Sene-Fiorese. 2015).

"The phototherapy equipment was developed by Laboratory Technology Support-LAT, Center for Research in Optics and Photonics Institute of Physics in São Carlos city at University of São Paulo-USP. The device is a prototype equipment that was submitted for registration as a new patent. The device is composed of four plates made of rubberized material measuring 20 by 20 centimeters (cm) each. Each two plates are connected to an electronic control box. The emitters of Ga-Al-As diode Lasers are distributed in the plate every 2.5 cm, totaling 16 emitters per plate and 64 emitters in total. The prototype is illustrated and irradiation parameters are [mentioned in Figure 1]" (Sene-Fiorese. 2015).

As I already hinted at in the previous paragraph, 805 nm is a pretty high wavelength. It's classified as near-infrared (near as in "near, but not in the visible spectrum"), which is too "long" to be seen by human beings... what it was not too long for, though, was to augment the beneficial effects the 48 workouts the subjects performed over the whole study period had on the women's body composition and metabolic health.

Figure 1: Overview of the changes in body comp and glucose metabolism in both groups (Sene-Fiorese. 2015).

What is (imho) pretty astonishing is yet not the fact that benefits occurred, but rather that these benefits were not just statistically significant, but also practically relevant. I mean you will certailny agree, that it makes a difference if you lose 11% or 6% body fat and improve your insulin sensitivity by 40% vs. 22% - right?

If we also take into account that the the scientists observed similarly profound differences when they analyzed the subjects adiponectin levels, which decreased by 7% in the SHAM group (bad) and increased by a whopping 20% (good!) in the PHOTO group, it's really hard to argue that the benefits wouldn't be worth the hassle, even though one may question the accuracy of the body fat / lean mass data which was measured with a body impedance, instead of a DEXA device. Since the overall results do support significant additive effects, there's simply no reason to assume that the BIA data would be incorrect. In addition, BIA is actually relatively useful if you measure relative changes in body composition. If you want a correct one-time reading of your body fat, though, I wouldn't rely blindly on what a BIA device says.

Bottom line: As the authors point out, their latest study "demonstrated for the first time that phototherapy enhances the physical exercise effects in obese women undergoing weight loss treatment promoting significant changes in inflexibility metabolic profile" (Sene-Fiorese. 2015). While I would probably have replaced the grammatically questionable and nondescript phrase"inflexibility metabolic profile" with something more tangible like "insulin sensitivity" or "glucose control," Sene-Fiorese's conclusion is generally right.

The same LLLT therapy has also been shown to almost double the muscle gains in a study with an 8-week eccentric training program | more

Furthermore their findings may be somewhat surprising, but they are by no means unrealistic in view of the existing evidence that demonstrates that phototherapy (or low-level-laser-therapy | LLLT) is effective as an adjuvant tool in non-invasive body countering. It has been shown to help w/ the reduction of cellulite, fatigue, pain, blood circulation, wound healing, lipid metabolism and recovery after exercise (Neira. 2002; Ferraresi. 2010; Aquino. 2013; Paolillo. 2013; Houreld. 2014), as well as to increase  the mitochondrial activity in irradiated cells by up-regulating genes involved in the mitochondrial complexes (Masha. 2013).

Unfortunately, our understanding of the underlying mechanisms that make LLLT so effective is still in its infancy. It is yet most likely that they are mediated on a cellular level by increases in PGC-alpha (the mitochondria builder) and sirtuins like SIRT-1. These proteins are all important regulators of mitochondrial function; and as you may remember from previous SuppVersity articles, they are also activated by resveratrol and a bunch of other supplements that have been shown to increase the health of the cells' mitochondria. How exactly the previously reported increases in muscle gains or the profoundly accelerated fat loss in the study at hand are brought about, will have to be elucidated in future studies, though | Comment on Facebook!

References:

• Aquino Jr, Antonio E., et al. "Low-level laser therapy (LLLT) combined with swimming training improved the lipid profile in rats fed with high-fat diet." Lasers in medical science 28.5 (2013): 1271-1280.
• Ferraresi, Cleber, et al. "Effects of low level laser therapy (808 nm) on physical strength training in humans." Lasers in medical science 26.3 (2011): 349-358.
• Foschini, Denis, et al. "Treatment of obese adolescents: the influence of periodization models and ACE genotype." Obesity 18.4 (2010): 766-772. 
• Houreld, Nicolette N. "Shedding light on a new treatment for diabetic wound healing: a review on phototherapy." The Scientific World Journal 2014 (2014).
• Masha, Roland T., Nicolette N. Houreld, and Heidi Abrahamse. "Low-intensity laser irradiation at 660 nm stimulates transcription of genes involved in the electron transport chain." Photomedicine and laser surgery 31.2 (2013): 47-53.
• Neira, Rodrigo, et al. "Fat liquefaction: effect of low-level laser energy on adipose tissue." Plastic and reconstructive surgery 110.3 (2002): 912-922.
• Paolillo, Fernanda Rossi, et al. "Infrared LED irradiation applied during high-intensity treadmill training improves maximal exercise tolerance in postmenopausal women: a 6-month longitudinal study." Lasers in medical science 28.2 (2013): 415-422.
• Sene‐Fiorese, Marcela, et al. "The potential of phototherapy to reduce body fat, insulin resistance and “metabolic inflexibility” related to obesity in women undergoing weight loss treatment." Lasers in Surgery and Medicine (2015).