In a randomised, double-blind trial by Leal Junior et al. (2008), 12 male volleyball players received 655 nm red laser therapy on the biceps before intense exercise. The treated group was able to perform significantly more repetitions to failure compared to placebo – an increase of about 8.5 reps versus only 2.7 in the placebo group (p = 0.0001). This amounted to roughly a threefold greater improvement in endurance for the red light group. The study concluded that red light preconditioning markedly delayed the onset of muscle fatigue. These results highlight that 655 nm red light (within Redviva’s ~660 nm range) can enhance muscle performance and resilience.

(PMID: 18817474)

In a crossover, placebo-controlled study by Leal Junior et al. (2009), ten male athletes (professional volleyball players) were treated with 830 nm near-infrared (NIR) laser on their biceps before a high-intensity exercise test. Researchers found the 830 nm laser significantly increased muscular endurance: subjects could perform more repetitions until exhaustion after NIR treatment (on average ~4–5 additional reps) compared to the placebo condition (p = 0.042)​. No adverse changes in blood lactate occurred with laser use. The authors concluded that 830 nm NIR therapy delayed muscle fatigue during intense exercise. As 830 nm lies in Redviva’s NIR wavelength range, this finding underscores the value of Redviva’s wavelengths for improving workout capacity. 

(PMID: 18649044)

In a controlled crossover trial by Leal Junior et al. (2010), nine male athletes received 810 nm laser phototherapy (using a 5-diode cluster) to their biceps just before exercise. The treated group showed enhanced performance, completing 14.5% more repetitions (39.6 ± 4.3 vs 34.6 ± 5.6 reps) than placebo (p = 0.037)​. Time to exhaustion was also 8% longer with laser (p = 0.034). Importantly, muscle recovery indicators improved: post-exercise blood lactate, creatine kinase (CK), and C-reactive protein levels were significantly lower in the 810 nm laser group than controls​, indicating reduced muscle stress and inflammation. Thus, 810 nm (within Redviva’s NIR range) not only acutely improved strength endurance but also accelerated recovery after exercise, illustrating the wavelength’s therapeutic value.

(PMID: 20436237)

In a double-blind crossover trial by Leal Junior et al. (2009), a cluster of 69 LEDs (mix of 660 nm red and 850 nm NIR) was applied to athletes’ biceps before exercise. The LED-treated athletes achieved ~13% greater muscle endurance than placebo – averaging 38.6 ± 9.0 contractions vs 34.2 ± 8.7 for placebo (p = 0.021. They also exercised longer (+11.6% time, p = 0.036) before fatigue. Moreover, markers of muscle strain were significantly reduced: post-exercise lactate, CK, and C-reactive protein levels were all lower with active LED therapy compared to controls​. The study demonstrates that using red (660 nm) and infrared (850 nm) light – both in Redviva’s wavelength range – in tandem can boost muscle performance and blunt the biochemical signs of exercise-induced muscle damage.

(PMID: 19731300)

In a randomised placebo-controlled study by Felismino et al. (2014), 22 active men performed an intensive biceps workout to induce muscle damage. One group received low-level laser therapy at 808 nm (1 J per point, applied at four points) between exercise sets. The laser group showed dramatically lower muscle damage markers in recovery. At 72 hours post-exercise, creatine kinase (CK) levels (a marker of muscle fiber damage) rose by only ~357% of baseline in the 808 nm laser group, versus an 841% spike in the placebo group (p < 0.05)​pubmed.ncbi.nlm.nih.gov. In other words, muscle damage was less than half of that in untreated participants. While strength eventually returned to baseline in both groups, the significantly blunted CK surge indicates faster healing and less inflammation with 808 nm treatment. This finding – with 808 nm being within ~810 nm Redviva range – supports the role of NIR light in reducing exercise-induced muscle injury and inflammation.

(PMID: 24005882)

In a randomised trial by Borges et al. (2014), 17 young men unaccustomed to heavy exercise performed 30 maximal eccentric biceps contractions (to induce DOMS – delayed onset muscle soreness). Immediately after, the test group received 630 nm LED therapy (20.4 J/cm²) on the exercised arm, while controls received a sham treatment. Over the next four days, the red light group experienced significantly better recovery. Muscle soreness ratings were lower, strength loss was less, and range-of-motion impairments were reduced at 24, 48, 72, and 96 hours post-exercise, compared to placebo​. By 96 hours the treated arms had recovered near baseline strength and flexibility, whereas placebo arms were still more affected. A single 630 nm light session thus markedly attenuated post-workout soreness and functional deficits. This lies in Redviva’s red light range, underscoring its effectiveness for speeding muscle recovery after strenuous exercise.

(PMID: 24258312)

In a double-blind controlled study by Douris et al. (2006), 27 healthy adults were split into three groups after inducing biceps DOMS via exercise: one group received daily phototherapy with 660 nm red + 880 nm infrared light (8 J/cm²) for 5 days, while a sham and a no-treatment group served as controls. The treated group reported significantly less muscle soreness at 48 hours post-exercise. On a 0–10 pain scale (VAS), pain in the red/NIR light group was markedly lower than in both the control (p = 0.01) and sham groups (p = 0.03)​. Similarly, a pain questionnaire showed lower scores in the light-treated group​. There were no differences in arm swelling or resting arm angle, but the clear reduction in perceived pain indicates that red light around 660 nm can alleviate DOMS. This aligns with Redviva’s use of 660 nm wavelengths to reduce post-exercise muscle pain and inflammation.

(PMID: 16875447)