Effects of Endurance Running Training Associated With Photobiomodulation on 5-Km Performance and Muscle Soreness: A Randomized Placebo-Controlled Trial

Acute dose-response effect of photobiomodulation therapy on 5-km running performance in trained runners: a randomized, double-blind, placebo-controlled, crossover study

Photobiomodulation therapy (PBMT) has been advocated as a potential intervention to improve muscle performance and recovery in the health and sports context. However, the short- and long-term effects of PBMT on endurance running performance remain under-researched and controversial. The purpose of this study was to investigate the acute dose-response effect of PBMT with light-emitting diodes (LEDs) on endurance performance and rating of perceived exertion (RPE; 6-20 Borg) during a 5-km running trial in recreational runners. In a crossover design, eighteen young adult runners (28.7 ± 7.8 years) were randomized to receive 1 of 4 PBMT conditions (placebo, 300, 900, and 1260 Joules [J]) 60 min before the 5-km running trial on four occasions, separated by a 2-wk washout period. The treatments were applied to the quadriceps, hamstrings, and gastrocnemius muscles of both legs using a device containing 200 LEDs (100 red and 100 infrared). The following variables were assessed: endurance performance (i.e. total time, mean velocity, and velocity in the split distances at the initial 200 m and every 400 m lap) and RPE in the split distances at the initial 200 m and every 400 m lap. Data normality and homogeneity were tested using Shapiro-Wilk's and Levene's tests, respectively. Differences between treatment conditions were assessed using the analysis of variance tests (one- or two-way ANOVA, depending on the comparisons), complemented by the Bonferroni post hoc test. There were significant time effects for the running velocity and RPE in the split distances (p < 0.0001), with no significant treatment-by-time interaction (running velocity, p = 0.59; RPE, p = 0.95). The mean velocity (p = 0.997), total time (p = 0.998), and total mean of the RPE (p = 0.91) were similar between treatment conditions. In conclusion, acute PBMT with LEDs at doses of 300, 900, and 1260 J is not recommended for improving endurance performance and RPE in the 5-km running trial in recreational runners.

A Meta-Analysis of Randomized Controlled Trials on the Effects of Photobiomodulation Therapy on Running Performance

Objective

To conduct a meta-analysis to investigate the effects of Photobiomodulation (PBM) therapy on running performance.

Introduction

PBM has recently been advocated as a valuable non-pharmacological ergogenic strategy, however, the efficacy of PBM on running performance remains unproven.

Methods

A computerized literature search was conducted until June 2023. The databases searched were PubMed/Medline, Embase, Scopus, SPORTDiscus, and Web of Science. Inclusion/exclusion criteria were determined through the PICO process. The running variables analyzed were time-trial or time-to-exhaustion. Results were combined with the standardized mean differences (SMD) and the 95% confidence intervals.

Results

Twelve studies fulfilled the inclusion criteria. No significant effects in favor of PBM were found (SMD = 0.13; p = 0.11). There was no effect considering the presence (SMD = 0.16; p = 0.38) and absence (SMD = 0.11; p = 0.25) of training, and there was no dose-response effect (p = 0.82).

Conclusion

Our findings indicate that PBM alone or combined with a training program does not improve running performance in terms of time-trial and time-to-exhaustion testing. More studies involving PBM plus training and doses higher than 1000 J are needed to determine if PBM is effective in improving running performance.

Can photobiomodulation improve quadriceps strength and endurance outcomes in asymptomatic adults? A double-blind randomized controlled trial

AIM

To explore the effect of photobiomodulation on quadriceps strength and endurance torques in asymptomatic adults.

METHODS

Twenty-eight asymptomatic adults were randomized to one of two interventions: photobiomodulation (n = 14) or sham (n = 14). Quadriceps strength was evaluated by maximum voluntary isometric contraction test (60°) and endurance by an elastic resistance in multiple-set knee extension/flexion repetitions using a traction dynamometer. The outcomes were measured at three time points: pre-baseline; baseline and; final assessment. The photobiomodulation was applied to the quadriceps and triceps surae muscles of each participant's dominant lower limb, using a cluster with 1 infrared laser diode and 3 led amber of 170 mW for 240 s over four consecutive days. The sham group went through the same procedures, but the equipment was off, and patients and assessors were blinded to the intervention. Reliability and minimal detectable change of the measures were obtained from the pre-baseline and baseline time points. Differences between interventions were tested by an analysis of covariance.

RESULTS AND DISCUSSION

There was no difference between photobiomodulation compared to sham in maximum isometric torque (mean difference (95% CI) = 0.008 (-0.29 to 0.31) and endurance torques (mean difference (95% CI) = 0.04 (-0.03 to 0.12). The mean difference was lower than the minimal detectable change for the maximum isometric torque (1.02 Nm.kg-1) and endurance torque (0.49 Nm.kg-1).

CONCLUSION

Photobiomodulation does not improve quadriceps strength and endurance outcomes in asymptomatic adults.

Peak Running Velocity vs. Critical Speed: Which One Is Better to Prescribe Endurance Training to Recreational Runners?

ABSTRACT

Figueiredo, DH, Figueiredo, DH, Manoel, FA, and Machado, FA. Peak running velocity vs. critical speed: which one is better to prescribe endurance training to recreational runners? J Strength Cond Res 37(9): 1783-1788, 2023-This study aimed to evaluate the effects of 5 weeks of training prescribed by peak running velocity obtained on the track (Vpeak_TR) and their respective time limit (Tlim), as well as by critical speed (CS), on physiological and endurance performance parameters in recreational runners. Twenty-two male runners were distributed into a Vpeak_TR group (GVP) and CS group (GCS) with a predefined program, alternating moderate-intensity continuous training and high-intensity interval training. Maximum oxygen uptake (V̇O2max), and its respective velocity (vV̇O2max), Vpeak_TR, Tlim at 100% Vpeak_TR, 5-km running performance, CS, and D' (maximum distance covered above CS) were assessed at pretraining and posttraining period. There was a significant increase from pretraining to posttraining in Vpeak_TR (GVP = 4.5 ± 3.1% vs. GCS = 7.5 ± 4.2%), vV̇O2max (GVP = 3.9 ± 3.8% vs. GCS = 8.6 ± 6.7%), and mean velocity 5-km (GVP = 5.6 ± 3.3% vs. GCS = 7.3 ± 3.5%) and decrease in 5-km time (GVP = -5.1 ± 3.0% vs. GCS = -6.8 ± 3.0%). CS and V̇O2max significantly improved in GCS (9.3 ± 8.4% and 6.0 ± 6.8%, respectively), with no difference for GVP (2.8 ± 5.6% and 1.3 ± 8.4%, respectively). No differences were observed between groups for all variables. These findings give further supports to the notion that both variables obtained on the track are valid tools to prescribed training in recreational runners.

Novel track field test to determine Vpeak, relationship with treadmill test and 10-km running performance in trained endurance runners

Objectives

The aim of this study was to determine the peak running velocity on the track field (V_{peak_TF}) based on the laboratory treadmill test (V_{peak_T}), and relate the V_peak values as well as their correlation with the 10-km running performance in trained endurance runners.

Method

Twenty male trained endurance runners (age: 29.5 ± 5.3 years; V̇O_2max: 67.5±17.6 ml · kg^-1·min^-1) performed three maximum incremental tests to determine the V_peak: one for V_{peak_T} determination and two to obtain V_{peak_TF} on the official track field (400 m), and a 10-km running performance. During the incremental tests, maximum heart rate (HR_max), maximal rating of perceived exertion (RPE_max), and peak lactate concentration (LA_peak) were determined.

Results

The results showed significant difference between the V_{peak_TF} and V_{peak_T} (18.1 ± 1.2 vs. 19.2 ± 1.5 km·h^-1, respectively), as well as the total time of the tests, the distance traveled and the RPE_max determined during the tests. A high correlation was observed between the V_peak values (r = 0.94), and between V_{peak_TF} and V_{peak_T} with 10-km running performance (r = -0.95 vs. r = -0.89, respectively).

Conclusions

The good agreement and association with V_{peak_T} and high correlation with 10-km running performance demonstrate that the novel track field test is efficient for V_{peak_TF} determination.

Photobiomodulation and Sports: Results of a Narrative Review

Benefits of photobiomodulation (PBM) have been known for several decades. More recently, PBM applied in sports offers a special chance to support the modeling of the performance and recovery. Increasingly complex physical activities and fierce competition in the world of sports generate a state of psycho-emotional and physical stress that can induce chronic fatigue syndrome, failure in physical training, predisposition to muscle damage, physical and emotional exhaustion etc., for which PBM could be an excellent solution. To evaluate and identify all risk factors and the influence of PBM on health and performance in sport and for a better understanding of its effects, we did a search for "Photobiomodulation and Sports" on PubMed, to update the PBM science applied in sports, and we retained for analysis the articles published from 2014 to date. The term "PBM" is recent, and we did not include previous studies with "low level laser therapy" or "LLLT" before 2014. In the present research, PBM has been shown to have valuable protective and ergogenic effects in 25 human studies, being the key to success for high performance and recovery, facts supported also by 22 animal studies. PBM applied creatively and targeted depending on sport and size of the level of physical effort could perfectly modulate the mitochondrial activity and thus lead to remarkable improvements in performance. PBM with no conclusive results or without effects from this review (14 studies from a total of 39 on humans) was analyzed and we found the motivations of the authors from the perspective of multiple causes related to technological limitations, participants, the protocols for physical activity, the devices, techniques and PBM parameters. In the near future, dose-response experiments on physical activity should be designed and correlated with PBM dose-response studies, so that quantification of PBM parameters to allow the energy, metabolic, immune, and neuro-endocrine modulation, perfectly coupled with the level of training. There is an urgent need to continuously improve PBM devices, delivery methods, and protocols in new ingenious future sports trials. Latest innovations and nanotechnologies applied to perform intracellular signaling analysis, while examining extracellular targets, coupled with 3D and 4D sports motion analysis and other high-tech devices, can be a challenge to learn how to maximize PBM efficiency while achieving unprecedented sports performance and thus fulfilling the dream of millions of elite athletes.

Peak Running Velocity or Critical Speed Under Field Conditions: Which Best Predicts 5-km Running Performance in Recreational Runners?

This study aimed to examine which variable, between the peak running velocity determined on the track field (V_{peak_TF}) and critical speed (CS), is the best predictor of the 5-km running performance in recreational runners. Twenty-five males performed three tests to determine the V_{peak_TF}, CS, and 5-km running performance on the track field, with a minimal interval of 48 h between each test. The V_{peak_TF} protocol started with a velocity of 8 km⋅h^–1, followed by an increase of 1 km⋅h^–1 every 3 min until volitional exhaustion, which was controlled by sound signals, with cones at every 25 m indicating when the participants were required to pass the cone’s position to maintain the required velocity. The participants performed three time trials (TTs) (1: 2,600 m; 2: 1,800 m; and 3: 1,000 m) on the same day, with a 30-min rest period to determine the CS through the combinations of three (CS₁,₂,₃) and two TTs (CS₁,₂, CS₁,₃, and CS₂,₃). The 5-km running performance time was recorded to determine the test duration, and the mean velocity (MV) was calculated. There was a significant difference observed between the V_{peak_TF} and the MV 5-km running performance. However, no differences were found between the CS values and the MV 5-km running performance. A correlation was observed between the V_{peak_TF} (R = −0.90), CS₁,₂,₃ (R = −0.95), CS₁,₃ (R = −0.95), and the 5-km running performance time. Linear regression indicated that the V_{peak_TF} (R² = 0.82), CS₁,₂,₃ (R² = 0.90), and CS₁,₃ (R² = 0.90) significantly predicted the 5-km running performance time. The CS results showed a higher predictive power for the 5-km running performance, slightly better than the V_{peak_TF}. Also, CS₁,₂,₃ and the CS₁,₃ presented the highest predictive power for the 5-km running performance of recreational runners.

Photobiomodulation Therapy at 808 nm Does Not Improve Biceps Brachii Performance to Exhaustion and Delayed-Onset Muscle Soreness in Young Adult Women: A Randomized, Controlled, Crossover Trial

Objective

This study aims to investigate the effects of laser photobiomodulation (PBM) at 808 nm on biceps brachii performance to exhaustion, rating of perceived exertion (RPE), and delayed onset muscle soreness (DOMS) in untrained young women.

Methods

Thirteen young women (20.1 ± 2.9 years) participated in a crossover study in which they received, in a counterbalanced manner, active and placebo laser PBM on two occasions (T1 and T2), separated by a 7-day washout period. During T1 and T2, participants received active (100 mW output power, irradiance of 35.7 W cm^–2, and total energy of 28 J/arm) or placebo laser irradiation on the biceps brachii muscle at 20 min before the repetitions-to-failure test [six sets at 60% of one-repetition maximum (1RM) until failure] for elbow flexion exercise. The number of repetitions performed and RPE over the six sets, as well as DOMS from basal up to 72 h after the repetitions-to-failure test, were recorded.

Results

There was a significant (time, p < 0.05) reduction in the number of repetitions performed and an increase in RPE over six sets, with no statistical differences between placebo and active laser conditions (treatment × time, p > 0.05). DOMS increased at 24 h postexercise and progressively returned to baseline after 72 h in both conditions (time, p < 0.05; treatment × time, p > 0.05).

Conclusion

Our results indicate that acute laser PBM at 808 nm does not improve biceps brachii performance to exhaustion, RPE, and DOMS in untrained women.

Effect of Photobiomodulation on Critical Swimming Velocity: A Randomized, Crossover, Double-Blind, and Placebo-Controlled Study

PURPOSE

To analyze the acute effect of photobiomodulation (PBM) on swimming critical velocity (CV).

METHODS

A total of 15 male federated swimmers (20.9 [2.4] y old) participated in this study. Three sets of front crawl were performed at distances of 100, 200, and 400 m to determine the CV under 3 experimental conditions: PBM (420 J), placebo (PLA), and control (C) in this randomized, crossover, double-blind, and placebo-controlled study. One-way analysis of variance for repeated measurements was used for statistical analyses.

RESULTS

The results showed that the prior application of PBM did not have ergogenic effects on CV and front crawl swimming performance: CV (PBM = 1.15 [0.15]; PLA = 1.20 [0.25]; C = 1.15 [0.14] m·s-1), swim time (ST) 100 m (PBM = 65.5 [6.3]; PLA = 65.2 [5.6]; C = 66.0 [5.9] s), ST 200 m (PBM = 148.5 [17.9]; PLA = 149.4 [16.4]; C = 150.1 [17.9] s), and ST 400 m (PBM = 327.7 [38.2]; PLA = 321.6 [47.7]; C = 329.5 [41.2] s).

CONCLUSIONS

A PBM application prior to front crawl swimming test did not significantly modify the CV, ST, physiological factors of metabolic fatigue, perceptual, and front crawl stroke efficiency parameters in competition swimmers covering distances of 100, 200, and 400 m.

Does Previous Application of Photobiomodulation Using Light-Emitting Diodes at Different Energy Doses Modify the Peak Running Velocity and Physiological Parameters? A Randomized, Crossover, Double-Blind, and Placebo-Controlled Study

Objective: This study aimed to verify the acute effects of photobiomodulation (PBM) using different doses of LED on peak running velocity (V_peak) and physiological parameters. Materials and methods: The study had a randomized, crossover, double-blind, and placebo-controlled format, in which 15 physically active males were submitted, besides the control (CON), to four conditions performed 5 min before the maximal incremental treadmill tests for the determination of V_peak: placebo (PLA) and three conditions of PBM application at different doses: PBM applied with 30 J per area (PBM₁), PBM applied with 120 J per area (PBM₂), and PBM applied with 180 J per area (PBM₃). The LED was applied using an equipment with 56 diodes of red light (660 nm; 50 mW/cm² and 1.5 J/cm² each diode) and 48 diodes of infrared light (850 nm; 150 mW/cm² and 4.5 J/cm² each diode). The PBM was applied in two regions of the quadriceps muscle, two regions of the femoral biceps muscle, and one region of the gastrocnemius muscle in both legs. Results: There was no difference among the outcomes from PBM irradiations and PLA condition for the variables, V_peak (CON = 13.4 ± 1.6; PLA = 13.4 ± 1.6; PBM₁ = 13.5 ± 1.7; PBM₂ = 13.4 ± 1.6; PBM₃ = 13.4 ± 1.7 km/h), similar to other variables associated with aerobic running performance analyzed during the maximal incremental treadmill tests for V_peak determination: lactate peak, heart rate, and rating of perceived exertion. Conclusions: We concluded that the application of different doses of PBM using LEDs did not modify V_peak and physiological and perceptual parameters.

The Effects of Whole-Body Photobiomodulation Light-Bed Therapy on Creatine Kinase and Salivary Interleukin-6 in a Sample of Trained Males: A Randomized, Crossover Study

Photobiomodulation therapy (PBMT) can be applied to the whole body as compared to the application of using single hand-held devices that isolate a smaller muscle area. The purpose of this study was to examine the effects of an acute dose of whole-body PBMT pre- and post-high-intensity resistance training on creatine kinase (CK) and salivary interleukin-6 (IL-6) in a sample of trained males. Twelve males (31 ± 8.3 years, 177.2 ± 5.4 cm, and 86.0 ± 7.5 kg) were part of a randomized, counterbalanced, cross-over design, whereby each participant performed a high-intensity resistance training session that consisted of the bench press, chin-up, and repeated sprints on two separate occasions. Each participant was assigned to either the PBMT or control condition on two separate weeks, with a 10-days washout period between the weeks. Creatine kinase was measured at baseline, 24, 48, and 72 h post-exercise. Salivary IL-6 was measured at baseline, 60, 90, and 120 min. A paired t-test showed no significant difference (p = 0.669) in the area under the curve (AUC) for CK during the PBMT (191.7 ± 48.3) and control conditions (200.2 ± 68.0). A Wilcoxon signed-rank test also showed no significant median difference (p = 0.155) in the AUC for salivary IL-6 during the PBMT (Mdn = 347.7) and control conditions (Mdn = 305.8). An additional Wilcoxon signed-rank test for CK percentage change from 24 to 72 h showed the PBMT condition (Mdn = −45%) to have a −18% median difference as compared to the control condition (Mdn = −41%). As such, whole-body PBMT does not significantly reduce the activity of salivary IL-6 or CK concentration during the 24 to 72-h recovery post-high-intensity resistance training.