Front Matter

158 Canine Sports Medicine and Rehabilitation

joint ROM. A 2016 study by Youssef and col­
leagues compared patients with knee osteoar­
thritis who participated in an exercise program
with or without LLLT treatment. While all sub­
jects demonstrated improved pain levels and
knee ROM, those subjects who received LLLT
demonstrated significantly greater improve­
ments in both areas (Youssef et al., 2016). Similar
findings were noted for OA in joints of the hand
(Baltzer et al., 2016) with improvement in all
aspects (pain, swelling, and joint mobility) fol­
lowing LLLT treatment.
When working with neurological patients,
LLLT may be able to improve mobility by
reducing spasticity, although the effects may be
temporary. Children with cerebral palsy are
often affected by spasticity, including in the
muscles of the jaw, which limits the ability to
open the mouth. Santos and colleagues deliv­
ered LLLT to the masseter and anterior tempo­
ral muscles for six treatments over 3 weeks. Up
to 6 weeks after treatments were completed, the
LLLT subjects continued to show increased
amplitude of mouth opening. By the sixth
week, however, measurements returned to
baseline (Santos et al., 2016). This reduction in
spasticity may provide the therapist with time
to perform more effective stretching, thereby
achieving more permanent results.

Therapeutic effects on muscle strength

Emerging research is showing that LLLT can
assist in reducing muscle fatigue. In a 2015
review, Leal‐Junior and colleagues found that
pre‐exercise LLLT led to reduced muscle
fatigue based on the subjects’ ability to perform
increased number of repetitions as compared to
controls (Leal‐Junior et al., 2015). In a progres­
sive intensity running study the use of LLLT
before exercise increased exercise performance
(as measured by VO2max and time to exhaus­
tion) and decreased oxidative stress and muscle
damage. The latter was evaluated by measur­
ing levels of superoxide dismutase (SOD), cre­
atine kinase (CK), and lactate dehydrogenase
(LDH) (De Marchi et al., 2012).
LLLT may also result in enhanced strength
gains. Vanin and colleagues found that healthy
volunteer subjects who received LLLT prior to
each training session over a 12‐week course
achieved significantly greater measurements of

maximum voluntary contraction and weight

lifted in 1‐repetition maximum as compared to

subjects who did not receive LLLT (Vanin et al.,

2016). Similar results have been noted in older

healthy adults. Toma and colleagues found

that, when combined with strength training,

LLLT promoted greater strength gains in

elderly women (Toma et al., 2016).

Considerations for clinical application

When using LLLT with canine patients, recom­

mendations include clipping or parting the hair

to maximize skin contact with the probe in

patients with thick, long coats. If using a heat­

ing laser this may be necessary in most patients.

More frequent movement of the probe is indi­

cated when treating over dark‐colored hair or

skin if using a high‐powered laser due to the

absorption of photon energy by melanin. The

absorption of the photons at a superficial level

is considered attenuation or loss of penetration

due to superficial absorption. This attenuation

requires a slightly higher total amount of

energy to create the full effect of the laser at

deeper target tissue. This energy has to be dis­

tributed slower to prevent injury to the tissue

from overheating. Laser photons are also

absorbed by the ink in tattoos causing them to

heat faster than pigmented tissue. For this rea­

son, applying laser over a tattoo should only be

done when the benefit outweighs the risk, and

again, the energy needs to be delivered slowly

to prevent overheating the skin. Topical medi­

cations should be washed off, and the clinician,

patient, and everyone in the room should wear

protective eyewear. Cryotherapy before LLLT

may provide additional benefit (Haslerud et al.,

2017) due to vasoconstriction decreasing water

and hemoglobin in the tissue, two of the major

laser­absorbing chromophores, allowing

deeper penetration secondary to less attenua­

tion. Joints to be treated should be placed in the

open or loose­packed position and, when pos­

sible, have traction applied to maximize energy

delivery to the joint capsule and cartilage sur­

faces (Figure 7.18). As inflammatory mediators

are deposited into the joint from the synovial

capsule, treating this structure is important

when the goal is reducing or preventing inflam­

mation. LLLT is considered safe to use over