Laser Therapy on Neck Pain in Adolescents

Muscle activity will be determined with the participant in a sitting position as well as during the neck muscle endurance test. The individuals will be submitted to bilateral EMG of the extensor muscles of the neck. The upper trapezius muscle will be used for the placement of the electrodes, which will be performed following the recommendations of the Surface EMG for Non-Invasive Assessment of Muscles (SENIAM). The participant will be instructed to execute three repetitions of each of the following for 15 seconds: rest, isometric contraction and isotonic contraction, with a one-minute rest interval between executions. The EMG signals will be captured using an eight-channel electromyograph, with a band frequency of 20 and 500 Hz, amplifier with a gain of 1000 Hz and > 100 dB rejection mode. The data will be processed using a 16-bit analog-digital converter, with a sampling frequency of 2000 Hz per channel. We hope the normalization of electrical activity in the musculature.

For the study of the cortisol, two saliva samples will collected (1 before and 1 after treatment) at the participant's home at a time scheduled between 9 am and 9 pm with one hour of fasting and rinsing of the oral cavity with water. The saliva will be collected on swabs, consisting of a small roll of cotton on a plastic rod encased in a plastic tube. The swab will remain in the mouth for two minutes. The cotton will subsequently be placed in another tube for centrifugation and the sample will be stored at -20o C until analysis. All samples will be analyzed in duplicate through enzyme-linked immunosorbent assays (ELISA), using the supernatant of the centrifuged saliva. Cortisol level in the samples prior to treatment will be considered the control for each individual.

Endurance will be measured following the removal of the neck support, when the participant (positioned in ventral decubitus on a cot with the arms alongside the body) will be instructed to secure his/her head in a stable position. A goniometer will be attached with Velcro immediately above the uppermost point of the ear, where a gravity inclinometer will be used on the sagittal plane. An extendable metric tape with a pendulum at the end will be connected between the eyebrows and extended until just above the floor. Fatigue or pain will be the criterion for discontinuation. The test will also be discontinued if the participant: is unable to sustain his/her head off the cot to avoid touching the pendulum to the ground more than five times or for more than five seconds; he loses more than 5o of retraction of the cervical spine for more than five seconds. The target time will be 600 seconds, but participants capable of surpassing this limit will be encouraged to do so.

Cervical range of motion will be measured for the following movements using a fleximeter: flexion, extension, right rotation, left rotation, right lateral flexion and left lateral flexion

The points proposed by Kendall will be used for the postural evaluation on three planes: coronal-anterior, coronal-posterior and sagittal. The findings will be recorded on a standardized chart containing the identification of the participant, date of birth, school grade and abnormalities observed on each of the three planes.

The SAPO allows a two-dimensional quantification of the body. The evaluation will involve the taking of photographs in a previously assembled booth, following the recommendations of the Brazilian Review of Kinematics/Anthropometrics and Human Performance. The participant will be positioned perpendicular to the axis of a digital camera located at distances of 3 and 1.5 meters on a tripod adjusted to half the height of the participant. Photographs will be taken from the front, right side, left side and back views. The bone references that will serve as guides for the angular calculation will be marked with polystyrene balls on: glabellum, right and left tragus, chin, right and left acromion, manubrium, right and left lateral epicondyle, C7 spinal process, intersection between medial margin and spine of the right and left scapula, lower angle of right and left scapula, right and left posterosuperior iliac spine and right and left anterosuperior iliac spine.

The IPAQ will be administered for the determination of physical activity in the previous week. The results will be classified based on the recommendations of the authors of the original questionnaire:sedentary; insufficiently active: insufficiently active A and insufficiently active B; Active: vigorous physical activity, moderate activity and any combined activity; Very active: vigorous physical activity and vigorous physical activity

The digital algometer will then be applied to the upper trapezius muscle at the midpoint between the seventh cervical vertebra and the acromion, bilaterally, with an increase in pressure until the participant reports the sensation of pain. The procedure will be performed three times and the mean value will be considered in the analysis.A point is considered painful when pain is reported with the application of less than 4 kg/cm2 of pressure. The scores of different tender points will be totaled to quantify individual total pain intensity in kg/cm2. It is hoped that pain intensity in the treated group will be diminished.