Effect of photobiomodulation on maximal lactate production rate on swimmers: a randomized, crossover, double-blind and placebo-controlled study

Abstract

Aim:

This study aimed to verify the acute effect of photobiomodulation (PBM) on maximal lactate production rate (VLa_max) in front crawl swimmers.

Methods:

Fifteen male swimmers (20.9 ± 2.4-year-old) participated in this study. Three sets of front crawls were performed at distances of 100-, 200- and 400-m under three experimental conditions: PBM (420 J), placebo (PLA) and control (C) in this randomized, crossover, double-blind and placebo-controlled study. PBM or PLA were applied or simulated before performance tests. One-way Anova for repeated measurements were used for statistical analyses.

Results:

The results showed that the prior PBM application did not affect VLa_max in front crawl swimmers: VLa_max 100-m (PBM = 0.20 ± 0.05 mmol·L^-1·s^-1; PLA = 0.20 ± 0.04 mmol·L^-1·s^-1 and C = 0.21 ± 0.04; mmol·L^-1·s^-1); 200-m (PBM = 0.09 ± 0.03 mmol·L^-1·s^-1; PLA = 0.08 ± 0.02 mmol·L^-1·s^-1 and C = 0.08 ± 0.02 mmol·L^-1·s^-1) and 400-m (PBM = 0.04 ± 0.01 mmol·L^-1·s^-1; PLA = 0.04 ± 0.01 mmol·L^-1·s^-1 and C = 0.03 ± 0.01 mmol·L^-1·s^-1). Nor effect swim time (ST) performance: ST 100 m (PBM = 65.5 ± 6.3 s; PLA = 65.2 ± 5.6 s; C = 66.0 ± 5.9 s); ST 200 m (PBM = 148.5 ± 17.9 s; PLA = 149.4 ± 16.4 s; C = 150.1 ± 17.9 s); ST 400 m (PBM = 327.7 ± 38.2 s; PLA = 321.6 ± 47.7 s; C = 329.5 ± 41.2 s).

Conclusions:

PBM application prior front crawl swimming tests did not significantly modify the VLa_max on swimmers covering distances of 100-, 200- and 400-m.

Keywords
low-level light therapy; ergogenic; front crawl; athletic performance; lactate

Introduction

The photobiomodulation (PBM) is an electromagnetic radiation, non-thermal neither harmful, that utilizes visible or invisible lights through laser or light emitting diode (LED) sources and it is being studied as a potential ergogenic resource to improve physical performance on competitive sports1, 2. As long term effects, studies have shown changes in the mitochondrial size and functionality, and acutely, an increase in the enzymatic activity of the entire mitochondrial respiration complex, and aerobic metabolism-related enzymes after PBM application, ensuring a high rate of adenosine triphosphate (ATP) synthesis via oxidative metabolism during exercise3, 4.

Another effect of PBM that may be related to aerobic metabolism is the improvement of microcirculation with hyperemia at the application site, favoring higher oxygen availability and rate of blood lactate clearance, potentially improving energetic status and the maintenance of muscle function in long-term exercise and at higher intensities5. These results suggest potential effect of PBM in the maximal lactate production rate (VLa_max) that represents the highest glycolysis demand and predicts anaerobic power6, 7. However, no study investigated the influence of PBM on VLa_max in swimmers or other populations.

Olbrecht8 considers VLa_max one of the most important physiological parameters to describe the conditioning profile in swimming, once the aerobic and anaerobic capacities determining the swimmer's maximal competition performance and the way the aerobic and anaerobic systems contribute to the metabolic energy supply during exercise.

Although no study has associated PBM and VLa_max, some authors examined the effect of PBM on other lactate parameters (e.g., LA_peak) determined after maximal tests9 -11. Peserico et al.9 conducted a study in which 15 physically active men were submitted to five maximal running performance conditions: control (C), three different PBM doses (30, 120 and 180 J per area) and placebo (PLA); they found no difference among the outcomes from PBM conditions and PLA for LA_peak. Similarly, Dellagrana et al.10 compared the effects of three different PBM doses (15, 30 and 60 J per site) on LA_peak in 15 recreational males' runners after maximal incremental treadmill tests, with no differences found between conditions.

On the other hand, Mezzaroba et al.11 in a study with 26 healthy, physically active, young men aimed to investigate the effect of prior PBM application on the responses of blood lactate clearance during the running incremental test; it was demonstrated positive responses of the prior LED (936 J) application in the blood lactate clearance compared to PLA. The main results were found mainly at 13^th and 15^th min post-exercise (LA_13-min and LA_15-min respectively). Authors believed these effects could be due to the improvement in microcirculation. Thus, these findings suggest that PBM application could improve peripheral blood lactate removal rate.

Concerning swimming, the only study found so far by Teixeira et al.12 investigated the effect of PBM on front crawl performances and showed that PBM was unable to improve physical performance or generate an ergogenic effect on maximal swimming tests, however no blood metabolic parameters were verified.

The objective of this study was to verify the acute effect of PBM on VLa_max in front crawl swimmers. Our hypothesis is that application of PBM prior to swimming tests can increase VLa_max.

Method

Participants

The sample size was calculated from a priori analysis for a group by time interaction comparison (F test, Anova for repeated measures, within-between interaction) according to an effect size of 0.25 (obtained from a pilot studies), power of 80% and significance level of 5%. We used the software Gpower^® 3.1 (Düsseldorf, Germany) for the calculation. The priori power analysis revealed a minimal sample of 15 participants.

Took place on this study 15 male swimmers (age 20.9 ± 2.4 y; height 178.0 ± 0.1 cm; body mass 76.0 ± 12.6 kg). The inclusion criteria were a performance ≥ 60% of the World record of 100-, 200-, or 400-m and compete at state events. Swimming best time of the participants were: 100-m = 57.1 ± 4.3 s; 200-m = 134.6 ± 15.45 s and 400-m = 282.1 ± 35.5 s. FINA (Fédération Internacionale de Natation) points of the participants were: 100-m = 485 ± 111.4 s; 200-m = 436.7 ± 129.1 s and 400-m = 479.5 ± 142.3 s. All swimmers compete at state level championships and two of them at national. Written, informed consent was obtained from participants, and ethical approval was granted by the local research ethics committee (2.554.517/2018).

Study design

The study had a randomized, crossover, double-blind and placebo-controlled design and all participants were following experimental conditions: PBM with light emitted diodes (LED - 420 J total doses applied), placebo (PLA) and control (C). The order of conditions (PBM, PLA and C) was randomized. The participants completed nine visits to the swimming pool and each participant performed the tests on different non-consecutive days under the three conditions over three weeks with a minimum interval of 48 h and a maximum of 72 h between tests. In each visit the participants performed just one distance in one condition. Participants were instructed to attend for testing well rested, well nourished, and well hydrated. They were also instructed to abstain from caffeine and to refrain from strenuous exercise before the tests13. The participants were in the transition of the preparatory period of training periodization.

Procedures

After the PBM or PLA application the participants had an individual warm-up of 15-20 min of self-paced intensity following 5 min of passive rest. In the C condition the participants performed the same warm-up as soon as they arrived at the test site. Three sets of front crawl were performed at distances of 100-, 200- and 400-m under three experimental conditions: PBM, PLA or control (C). Each performance, in an indoor 25-m swimming pool heated to 28 °C, started inside the pool with an impulse from the edge of the pool after a beep, and the time taken to swim each distance was recorded using a manual chronometer. The order in which the participants performed each distance was randomized.

For the PBM application it was used the LED equipment (THOR-LX2^®, Thor Photomedicine Ltd, London, UK) with two clusters of 104 infrared LED diodes each. The application was conducted by an assistant researcher who controlled the device on or off (PBM: LED 420 J total dose or PLA, respectively). The application of the PBM had a total duration of approximately 1 min and 45 s, 15 s per point (30 J per point10), as shown in Table 1. The same procedures were used in the PLA and PBM conditions, respecting the presence or absence of light emission for each condition. The irradiation intervention started 15-20 min before the swimming test, in contact mode with the LED cluster held stationary with slight pressure at a 90° angle to the skin at each of the seven treatment points. PBM was applied to the upper limbs and trunk muscles (clavicular portion of pectoralis major; latissimus dorsi; lateral deltoid and triceps brachii - long and lateral head) and lower limbs (recto femoris on the quadriceps muscle, middle portion of biceps femoris, and a region of the gastrocnemii muscle) following the axis of distribution of muscle fibers in both legs (seven points each side, total of 14 points on body).

Table 1
Parameters of PBM application.

Number of diodes: 104:	56 diodes of 660 nm (red light); 48 diodes of 850 nm (infrared)
Wavelength:	Mixed - 660 and 850 nm
Power output (each diode):	10 mW (660 nm) and 30 mW (850 nm)
Diode area:	0.2 cm2
LED cluster area:	46.3 cm2
Power density (each diode):	50 mW/cm2 (660 nm) and 150 mW/cm2 (850 nm)
Energy density (each diode):	0.75 J/cm2 (660 nm) and 2.25 J/cm2 (850 nm)
Exposure time (per site):	15 s
Total energy irradiated (each diode):	0.15 J (660 nm) and 0.45 J (850 nm)
Total energy irradiated (each site):	30 J
Total energy irradiated on body:	420 J
Number of application sites (each body side):	7 sites
Total number of application sites on body:	14 sites
Total exposure time:	1 min: 45 s

Maximal lactate production rate (VLa_max)

VLa_max was calculated, as shown below, by the difference between maximal interpolated post-exercise La (La_maxPost) and resting La (La_pre) that was divided by the difference between swimming test time (t_test) and the period at the beginning of exercise for which no lactate formation is assumed t_alac. The time considered to determined t_alac were 4 s for 100-m front crawl swimming and 8 s for 200- and 400-m front crawl swimming14, 15. This swim-specific calculation (Equation (1)) enables to estimate glycolytic capacity for exercises until 600 s¹⁶.

(1) $${VLa}_{max}\left[\text{mmol}·{\text{L}}^{-1}\text{·}{\text{s}}^{-1}\right]=\frac{{La}_{maxPost}(\text{mmol}·{\text{L}}^{-1})-{La}_{pre}\left(\text{mmol}·{\text{L}}^{-1}\right)}{t_{test}\left(\text{s}\right)-t_{alac}\left(\text{s}\right)}$$

To determine the lactate concentrations, earlobe capillary blood samples (25 µL) were collected into a capillary tube. The samples were subsequently determined by electroenzymatic methods using the YSI 2300 STAT^® (Yellow Springs, OH) automated analyzer.

Statistical analyses

Data were analyzed using the Statistical Package for the Social Sciences v.24.0 (SPSS^® Inc., USA). The Shapiro-Wilk test was used to check the normality of the data distribution and data are presented as mean ± standard deviation (SD). Anova for repeated measures was used to compare the three conditions (PBM, PLA and C). It was used the Mauchly's test of sphericity to determine data normality, and if necessary, the Epsilon adjustment Greenhouse-Geisser to determine main effect. The analyses were completed with the Bonferroni post hoc. Statistical significance was set at p < 0.05. As complementary analysis the effect size (ES), (Cohen's d)17 was calculated to determine the magnitude of change in each condition using the following equation:

(2)$$ES=(M1-M2)÷\left(\right(SD1+SD2)÷2)$$

Note that M1 and M2 the average of each condition, SD1 and SD2 the respective standard deviations. The ES was classified according to Cohen17 as: ≤ 0.20 (trivial), between 0.21 and 0.50 (small), between 0.51 e 0.80 (moderate) and > 0.80 (large).

Results

The values for time at 100-, 200- and 400-m front crawl swimming are presented in Table 2. The mixed Anova for repeated measures didn't indicate statistically significant differences between conditions.

Table 2
Mean ± SD of time to complete distances of 100-, 200- and 400-m front crawl all out on the three different conditions.

	D (m)	PBM	PLA	C	F	p
	100	65.5 ± 6.4	65.2 ± 5.6	66.0 ± 6.0	0.664	0.523
Time (s)	200	148.6 ± 17.9	149.4 ± 16.4	150.1 ± 17.9	0.628	0.489
	400	327.7 ± 38.3	321.6 ± 47.7	329.6 ± 41.2	1.093	0.320

Note: n = 15; Time (s), swim time to perform the distances; D (m), distances of tests; PBM, photobiomodulation; PLA, placebo; C, control.p < 0.05.

The values for VLa_max at 100-, 200- and 400-m front crawl swimming are demonstrated in Table 3. The mixed Anova for repeated measures didn't show statistically significant differences between conditions. Qualitative analysis showed a large ES for PBM vs. C (1.00), PLA vs. C (1.00) at 400-m front crawl swimming and small ES for PBM vs. PLA (0.40) and PBM vs. C (0.40) at 200-m front crawl swimming. For the other comparisons ES were trivial on the three distances.

Table 3
Comparison of maximal lactate production rate accumulation rate for distances of 100-, 200- and 400-m in front crawl swimming in three different conditions.

	PBM	PLA	C	F	p
VLamax 100 m [mmol·L-1·s-1]	0.20 ± 0.05	0.20 ± 0.04	0.21 ± 0.04	0.091	0.913
VLamax 200 m [mmol·L-1·s-1]	0.09 ± 0.03	0.08 ± 0.02	0.08 ± 0.02	0.137	0.872
VLamax 400 m [mmol·L-1·s-1]	0.04 ± 0.01	0.04 ± 0.01	0.03 ± 0.01	0.221	0.802

_maxp < 0.05.

Discussion

The objective of this study was to verify the acute effect of PBM on VLa_max in front crawl swimmers. The main findings showed that prior PBM application using LED did not modify the VLa_max at 100-, 200- and 400-m in front crawl swimming, contrary to the initially formulated hypothesis.

Concerning the effect of PBM on VLa_max, no previous study examined this assumption. However, it was already investigated the effect of prior PBM application on other lactate parameters obtained after maximal tests9 -11, 17.

For example, Peserico et al.9 found no significant difference among PBM conditions and PLA for LA_peak values (PLA = 8.9 ± 1.8 mmol·L^-1; PBM 30 J = 9.4 ± 2.3 mmol·L^-1; PBM 120 J = 9.4 ± 2.1 mmol·L^-1; PBM 180 J = 8.7 ± 2.7 mmol·L^-1). Dellagrana et al.10 also found no difference in the LA_peak concentration between PBM 420 J (10.9 ± 2.5 mmol·L^-1), PBM 840 J (10.8 ± 2.9 mmol·L^-1) and PBM 1680 J (10.7 ± 2.42 mmol·L^-1) and PLA (10.9 ± 3.1 mmol·L^-1).

Nevertheless, Mezzaroba et al.11 investigated the blood lactate concentration after two incremental running tests with previous PLA or PBM application and found a positive response at PBM condition in the blood lactate clearance, especially at 13^th and 15^th min after the test (LA_13-min: PLA = 7.7 ± 1.9; PBM = 7.2 ± 1.3 mmol·L^-1; LA_15-min; PLA = 7.3 ± 2.8; PBM = 6.6 ± 1.3 mmol·L^-1).

In addition, Machado et al.17 aimed to examine the recovery effects of PBM applied between two running time trials on blood lactate in 11 physically active males' recreational runners. LA concentrations were verified before and after each test, 24-h, and 48-h after. The results from 24-h later showed that the effect size between PBM and PLA condition was moderate (the concentrations for PBM condition were lower than for PLA condition; ES: -0.62).

Considering the present study and the absence of PBM effects on VLa_max, it may be due the use of lower doses of PBM (30 J) per point on large muscles. Beyond that, there are peculiarities of the aquatic environment that must be considered, the hydrostatic pressure for example, lead to changes in cardiovascular parameters, heart rate is significantly reduced as a compensation for the high stroke volume caused by the body position in decubitus, water temperature, and the body weight discharge caused by buoyancy18.

These events can generate an increase in cardiac output, stroke volume, and perfusion in non-muscular tissues of swimmers, in addition to facilitating the venous return and consequently the removal of blood lactate19, 20. Considering that, water sports could minimize the effect of PBM application therapy due to the physical properties that are already acting on the body.

As main limitation of our study, we point out the low dose (30 J)21 used and the application at only one point in the large muscle groups, which was based on previous studies with results that pointed to a possible effect of PBM on performance variables and indicators of aerobic metabolism22, 23.

Conclusion

We conclude that PBM applied prior swimming tests did not affect the VLa_max values at the distances of 100-, 200- and 400-m front crawl in competitive swimmers. In terms of practical application, based on these results, there were not enough evidence to recommend the use of PBM as an ergogenic resource by coaches and swimmers with the intention of improving performance in crawl swimming events.

References

• 1. de Carvalho G, Gobbi A, Gobbi RB, Alfredo DMN, Furquim THC, Barbosa RI, et al. Photobiomodulation by light emitting diode applied sequentially does not alter performance in cycling athletes. Lasers Med Sci. 2020;35(8):1769-79. doi
  » https://doi.org/10.1007/s10103-020-02973-9
• 2. Dellagrana RA, Rossato M, Orssatto LBR, Sakugawa RL, Baroni BM, Diefenthaeler F. Effect of photobiomodulation therapy in the 1500 m run: an analysis of performance and individual responsiveness. Photobiomodulation, Photomedicine, Laser Surg. 2020;38(12):734-42. doi
  » https://doi.org/10.1089/photob.2019.4785
• 3. Albuquerque-Pontes GM, Vieira R de P, Tomazoni SS, Caires CO, Nemeth V, Vanin AA, et al. Effect of pre-irradiation with different doses, wavelengths, and application intervals of low-level laser therapy on cytochrome c oxidase activity in intact skeletal muscle of rats. Lasers Med Sci. 2015;30(1):59-66. doi
  » https://doi.org/10.1007/s10103-014-1616-2
• 4. Buravlev EA, Zhidkova TV, Vladimirov YA, Osipov AN. Effects of laser and LED radiation on mitochondrial respiration in experimental endotoxic shock. Lasers Med Sci. 2013;28(3):785-90. doi
  » https://doi.org/10.1007/s10103-012-1155-7
• 5. Larkin KA, Martin JS, Zeanah EH, True JM, Braith RW, Borsa PA. Limb blood flow after class 4 laser therapy. J Athl Train. 2012;47(2):178-83. doi
  » https://doi.org/10.4085/1062-6050-47.2.178
• 6. Olbrecht J. Lactate production and metabolism in swimming. In: World Book of swimming from science to performance. New York, Nova Science Publishers, Inc.; 2011. p. 255-75.
• 7. Sperlich B, Zinner C, Heilemann I, Kjendlie PL, Holmberg HC, Mester J. High-intensity interval training improves VO2peak, maximal lactate accumulation, time trial and competition performance in 9-11-year-old swimmers. Eur J Appl Physiol. 2010;110(5):1029-36. doi
  » https://doi.org/10.1007/s00421-010-1586-4
• 8. Olbrecht J. The use of blood lactate by elite swimmers. Sport & Medicine Today. 2001;1:47-51.
• 9. Peserico CS, Garozi L, Zagatto AM, Machado FA. 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. Photobiomodulation, Photomedicine, Laser Surg. 2020;38(12):727-33. doi
  » https://doi.org/10.1089/photob.2019.4791
• 10. Dellagrana RA, Rossato M, Sakugawa RL, Baroni BM, Diefenthaeler F. Photobiomodulation therapy on physiological and performance parameters during running tests: dose-response effects. J Strength Cond Res. 2018;32(10):2807-15. doi
  » https://doi.org/10.1519/JSC.0000000000002488
• 11. Mezzaroba PV, Pessôa Filho DM, Zagatto AM, Machado FA. LED session prior incremental step test enhance VO2maxin running. Lasers Med Sci 2018;33(6):1263-1270. doi
  » https://doi.org/10.1007/s10103-018-2475-z.
• 12. Teixeira CL, Mezzaroba PV, Machado FA. Effect of photobiomodulation on critical swimming velocity: a randmized, crossover, double-blind, and placebo-controlled study. Int J Sports Physiol Perform 2021;16(7):1035-42. doi
  » https://doi.org/10.1123/ijspp.2020-0264.
• 13. Mezzaroba PV, Papoti M, Machado FA. Comparison between lactate minimum and critical speed throughout childhood and adolescence in swimmers. Pediatr Exerc Sci. 2014;26(3):274-80. doi
  » https://doi.org/10.1123/pes.2013-0181
• 14. Hauser T, Adam J, Schulz H. Comparison of calculated and experimental power in maximal lactate-steady state during cycling. Theor Biol Med Model. 2014;11(1):1-12. doi
  » https://doi.org/10.1186/1742-4682-11-25
• 15. Heck H, Schulz H, Bartmus U. Diagnostics of anaerobic power and capacity. Eur J Sport Sci. 2003;3(3):1-23. doi
  » https://doi.org/10.1080/17461390300073302
• 16. Olbrecht J, Mader A, Heck H, Hollmann W. The importance of a calculation scheme to support the interpretation of lactate tests. In: Swimming Sciences VI, Biomechanics and Medicine. London, E & FN Spon; 1992. p. 243-9.
• 17. Machado FA, Peserico CS, Mezzaroba PV, Manoel FA, da Silva DF. Light-emitting diodes (LED) therapy applied between two running time trials has a moderate effect on attenuating delayed onset muscle soreness but does not change recovery markers and running performance. Sci Sport. 2017;32(5):286-94. doi
  » https://doi.org/10.1016/j.scispo.2016.06.010
• 18. Pendergast DR, Lundgren CEG. The underwater environment: cardiopulmonary, thermal, and energetic demands. J Appl Physiol. 2009;106(1):276-83. doi
  » https://doi.org/10.1152/japplphysiol.90984.2008
• 19. Leahy MG, Summers MN, Peters CM, Molgat-Seon Y, Geary CM, Sheel AW. The mechanics of breathing during swimming. Med Sci Sports Exerc. 2019;51(7):1467-76. doi
  » https://doi.org/10.1249/MSS.0000000000001902
• 20. Garzon M, Juneau M, Dupuy O, Nigam A, Bosquet L, Comtois A, Gayda M. Cardiovascular and hemodynamic responses on dryland vs. immersed cycling. J Sci Med Sport. 2015;18(5):619-23. doi
  » https://doi.org/10.1016/j.jsams.2014.08.005
• 21 Dellagrana RA, Rossato M, Sakugawa RL, Baroni BM, Diefenthaeler F. Photobiomodulation therapy on physiological and performance parameters during running tests. J Strength Cond Res. 2018;32(10):2808-15. doi
  » https://doi.org/10.1519/JSC.0000000000002488
• 22 Alves MAS, Pinfild CE, Nilsen Neto L, Lourenço RP, Azevedo PHSM, Dourado VZ. Acute effects of low-level laser therapy on physiologic and electromyographic responses to the cardiopulmonary exercise testing in healthy untrained adults. Lasers in Medical Science. 2014;29:1945-51. doi
  » https://doi.org/10.1007/s10103-014-1595-3
• 23 Ferraresi C, Kaippert B, Avci P, Huang YY, Souza MVP, Bagnato VS, et al. Low-level laser (light) therapy increases mitochondrial membrane potential and ATP synthesis in C2C12 myotubes with a peak response at 3-6 h. Photochem Photobiol. 2015;91:411-16. doi
  » https://doi.org/10.1111/php.12397

Associate Editor: Angelina Zanesco0000-0002-2515-1871. ¹Universidade Metropolitana de Santos, Faculdade de Medicina, Santos, SP, Brazil; ²Universidade Estadual Paulista “Júlio de Mesquita Filho”, Departamento de Educação Física, Instituto de Biociências, Rio Claro, SP, Brazil. E-mail: [e-mail].

Publication Dates

• Publication in this collection
  02 Dec 2022
• Date of issue
  2022

History

• Received
  21 Oct 2021
• Accepted
  06 Sept 2022