Photobiomodulation Therapy on Performance in Successive Cycling Tests

Summary

The goal of this study was to investigate the effects of Photobiomodulation therapy (PBMT) on performance, oxygen uptake (VO2 kinetics), and lower limb muscle oxygenation during three successive time-to-exhaustion tests (TTEs) in cyclists. This was a double blind, randomized, crossover, placebo-controlled trial study. Sixteen cyclists (\~23 years old), with a cycling training volume of \~460 km/week, volunteered for this study. In the first session, cyclists performed a maximal incremental test to determine maximal oxygen uptake and maximal power output (POMAX). In the following sessions, cyclists performed three consecutive TTEs at POMAX. Before each test, PBMT (135 J/thigh) or a placebo (PLA) PBMT was applied to both thighs. VO2 amplitude, O2 deficit, time delay, oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), and total hemoglobin (tHb) were measured during tests on the right vastus lateralis. The PBMT, applied before three successive TTE, increased performance of the first and second TTE (\~10-12%) tests, speed of VO2 and HHb kinetics during the first test, and increased peripheral muscle oxygenation (increase in HHb and tHb) in the first and second exhaustion tests. However, the PBMT effects were attenuated in the third TTE, as performance and all the other outcomes were similar to the ones from the PLA intervention. In summary, PBMT application increased the first and second successive TTEs, speed of VO2, and muscle oxygenation.

Conditions

• Photobiomodulation Therapy
• Cyclists
• Performance

Interventions

DEVICE

Photobiomodulation Therapy

Phototherapy treatment (Photobiomodulation therapy or placebo) was performed using a Photobiomodulation therapy device (Vectra Genisys Systems, Chattanooga Group, Dallas, TX, USA). The cluster probe consisted of five low-level laser therapy diodes (850 nm) and 28 light emitting diodes therapy (670 nm, 880 nm, and 950 nm). Photobiomodulation therapy was applied in nine sites of each quadriceps femoris muscle . A dosage of 15 J per site led to a total energy of 135 J per thigh, effectively increasing cycling performance in a previous study. We chose to apply Photobiomodulation therapy specifically to the quadriceps femoris because this muscle group is of utmost significance in generating torque and propelling the pedaling cycle. Its pivotal role in cycling performance made this muscle a prime target for the Photobiomodulation therapy intervention in our study.

DEVICE

Placebo Photobiomodulation

The placebo treatment was performed in exactly the same manner as the Photobiomodulation therapy treatment, but with the device switched off, and the cluster was held stationary in contact with the skin at a 90° angle, with light pressure on the skin. The total application time of Photobiomodulation therapy or placebo was \~5 min for both limbs (9 points per thigh = 18 points × 16 s per point) before each time-to-exhaustion test.

Sponsors & Collaborators

• Marco Aurélio Vaz, PhD

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

QUADRUPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

30 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2014-07-14

Primary Completion

2023-05-23

Completion

2023-10-11

Countries

• Brazil

Study Locations