March/April 2020 - 22

Laser and Light Therapy
Why are More Sports Healthcare
Professionals Seeing the Light?
By Kenneth T. Cieslak, DC, LAT, ATC, CSCS
Contributing Writer
T
.he use of light therapy for therapeutic purposes has
.been around for over 50 years. In 1967, Mester, et
.al. 1
reported on the effects of laser biostimulation
for the treatment of musculoskeletal conditions. Since then,
the use of therapeutic light has rapidly gained acceptance in
both the medical and rehabilitation communities.
LASER, which stands for " light amplification by
stimulated emission of radiation, " is a type of device that can
now be found in a variety of settings, with most professional
sports teams and many collegiate division I programs
utilizing this modality as part of their treatment protocols.
As technology has progressed, these devices have become
more sophisticated, as well as more affordable.
The vast majority of laser therapy being utilized in
the therapeutic setting is referred to as Low Level Laser
Therapy, or LLLT devices, which are also referred to as cold
lasers. These are low-powered devices which primarily
create non-thermal effects, and are relatively safe to use.
Other forms of light therapy include high powered lasers,
and light emitting diode (LED) devices.
The science behind these devices is based upon the
concept of photobiomodulation, which suggests that the
penetration of light deep into tissues can initiate a multitude
of both physical and chemical changes. This is primarily
dependent upon the type of light form used, as well as the
wavelength and dosage. Light with a wavelength in the red
to near infrared region (600nm- 905nm) is most commonly
utilized in these devices 2
.
When therapeutic light is sent into the tissues, some of it
20 | Training & Conditioning | March/April 2020
is absorbed into the epidermis, however photons can reach
deeper structures as well. One of the cellular targets of this
type of therapy is the mitochondria of the cell, in particular
Cytochrome c oxidase (COX). COX is a terminal enzyme
of the electron transport chain and plays a vital role in the
bioenergetics of the cell 3
. It is believed that an increase in
electron transport activity can lead to an increase in the
production of ATP as well, which is vital to cell energetics.
Another biochemical target of laser therapy is the
production of Nitrous Oxide (NO). It has been proposed that
laser irradiation could lead to the dissociation of NO from the
COX enzyme, which has the potential benefit of preventing
the inhibition of COX, leading to an increase in cellular
respiration as well (Farivar-18). This is thought to lead to a
light-mediated vasodilation in the tissues 4
. It is also thought
that the inhibition of NO can lead to a decrease in cell death
(induced by NO) as well 5
.
Studies by Karu 6
suggest that LLLT produces a shift
in the cell toward greater oxidation by an increase in
the generation of reactive oxygen species (ROS). This
is associated with a change in the activity of cellular
signaling pathways as well as gene expression within the
cell. Furthermore, this activity can be associated with an
increase in protein synthesis, nucleic acid synthesis, and cell
cycle progression 7
.
So what parameters should a clinician consider, when
deciding what type of light therapy to use. With regard
to low level laser therapy, most of the devices work by
exhibiting a bi-phasic dose response curve, otherwise
March/April 2020

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