Cranial Laser Reflex Technique for Hamstring Function

First Visit: Subjects who met the inclusion criteria and gave consent completed a brief
questionnaire on their activity level, history of hamstring injuries, and perceived hamstring
tightness and were randomized to one of the following for the first treatment period: 1)
active CLRT; or 2) sham laser.

After randomization, subjects were asked to complete the three functional hamstring tests:
90-90 Knee Extension Angle (KEA) to assess flexibility, handheld dynamometry (HHD) for
strength, and pain pressure threshold (PPT).

Assessments. KEA: The 90-90 Knee Extension Angle test is a functional assessment designed to
assess lower extremity flexibility and is considered the gold standard for hamstring length.
The participant began in the supine position on a treatment table. The tested extremity (the
right leg in each subject) was placed in a 90° hip and 90° knee position with the
contralateral lower extremity placed flat on the table. A digital inclinometer was
consistently placed at the level of the medial malleoli and the superior pole of the patella.
The examiner maintained 90° of hip flexion. Pelvic position was monitored by palpation of the
anterior superior iliac spine and lumbar spinous processes to maintain a neutral pelvic
position. The examiner passively extended the knee to the point of a ''strong, but tolerable
stretch," as reported by the subject. The examiner read the angle of the inclinometer and
recorded the mean value of three attempts. A greater angle indicates greater degree of
flexibility.

Hand held Dynamometry (HHD) is currently considered a reliable and valid measurement of peak
muscle contraction. The subject began prone on the table with right leg bent to 90°. The
tester placed the dynamometer (microFET2; Hoggan Health Industries, Salt Lake City, UT) at
the heel of the participant and applied force to the heel, gradually increasing in 3 to 5
seconds. Participants was instructed to resist the applied force and maximally contract the
hamstring muscle against the HHD device. The test ended once they are no longer able to
resist the force and the leg begins to move (break point). The investigator recorded the mean
value of three attempts.

Pain Pressure Threshold (PPT) is a reliable, accurate and valid method for measuring muscle
pain sensitivity and response to treatment. The digital algometer (FDX, Wagner Instruments,
Greenwich, CT) is a hand-held muscle tester with a range of 0-100 lbf that consists of a
padded disc with a diameter of 0.5" attached to a microprocessor-control unit that measures
peak force (pounds or kilograms). The unit has a digital readout for peak-applied pressure
and provides a built-in calibration routine that verifies a valid calibration. In order to
determine PPT, the researcher applied the tip of the algometer to a tender spot in the
participant's hamstrings and increased the amount of pressure until the participant verbally
informed the researcher when the sensation of pressure became pain. At this point the
algometer was removed and the peak force recorded. The mean of three repeated measures was
reported.

Intervention: Cranial Laser Reflex Technique (CLRT) is a novel complementary and alternative
(CAM) medicine intervention for musculoskeletal conditions that incorporates principles of
laser acupuncture with chiropractic cranial reflexology. Subjects wore protective eyewear.
The hamstring reflexes are two lines on the posterior portion of the top of the head,
approximately 2 cm long and 2 cm apart, running parallel to the sagittal suture. The
posterior end of the reflexes can be located by finding the vertex, or CZ point in the
standardized 10-20 EEG system, and moving laterally approximately 1 cm.

The aperture of the laser probe was placed at the posterior end of the reflex (b), turned on
and moved anteriorly to point (a) at a speed of approximately 2 cm/s. The laser was turned
off and quickly returned to the starting point, turned on and moved again. This was repeated
for a total of 30 times. The probe skimmed the surface of the scalp, moving aside as much
hair as possible.

Device: The treatment device used in this study is a Class IIIB 810nm 200 milliwatts (mW)
near-infrared diode laser (THOR Photomedicine Ltd, Great Britain) that is currently marketed
in the US. The laser probe is FDA-cleared and classified as a non-significant risk device.
The spot size is 0.0364 cm^2, and the treatment time is 30 seconds. Current best-practice
recommendations for laser acupuncture recommend a dosage between 1-4 J/cm^2 per point. Since
the CRP is a line of 2 cm, for the purposes of calculating dosage, it was treated as a series
of 10 connected points each with a diameter of 2mm. With the scanning rate of 2cm/s, each
"point" on the line received 1/10 of each pass, totaling 3s (out of 30s total) exposure time
per point. The dose per point for this intervention is calculated to be approximately 1.65
J/cm^2.

There was a one-week washout and the subject will return for the second treatment period.

Primary Outcome: Hamstring flexibility (90-90 Knee Extension Angle, KEA) A clinically
significant effect size is an increase of 5 degrees. The investigator recorded the mean value
of three attempts. Hypothesis: CLRT will increase hamstring flexibility.

Secondary Outcomes:

1. Hamstring Strength as assessed by Handheld Dynamometry. HHD . The investigator recorded
the mean value of three attempts. Hypothesis: CLRT will have a neutral to positive
effect on hamstring strength.

2. Pain Pressure Threshold. The mean of three repeated measures was reported. An increase
in PPT signifies an increase in pain tolerance. Hypothesis: CLRT will increase pain
tolerance.

3. Age, gender, activity level, perceived hamstring tightness, perceived hamstring
flexibility and perceived hamstring strength were assessed at baseline and subsequent
follow up visit. Results were stratified by these variables to assess interaction with
treatment.

Sample Size and Power: Based on previously published results, a mean increase of 5º on the
KEA (e.g., from 135º to 140º) is considered to be clinically meaningful, assuming a common
standard deviation of 15º. It is also assumed that correlation between repeated measurements
from the same individual will be at least 0.75 (likely a conservative assumption). Under
these assumptions, enrolling 38 participants would provide at least 80% power using a
two-sided test at the 0.05 level.

Inclusion Criteria:

1. Between 18-35 years of age

2. All genders

3. Willing to complete two study visits over 2-3 weeks

4. Able to read and communicate in English

Exclusion Criteria:

1. Current lower back condition with pain, numbness or tingling that radiates down the
legs

2. Active treatment for a major medical illness, such as heart disease, uncontrolled
diabetes or hypertension, malignancy, autoimmune, or immune deficiency disorder

3. History of vasculitis, intracranial mass, clotting disorder (including
medication-induced, e.g., warfarin)

4. Current skin malignancy on scalp

5. Cognitive dysfunction preventing informed consent

6. Pending or currently receiving benefits from personal injury litigation, including
worker's compensation

7. Chronic long-term disability related to lumbosacral injury/symptoms

8. Epilepsy