This randomized crossover study aims to address an important gap in manual therapy by examining the acute physiological effects of different Graston Technique application speeds (60 BPM vs. 120 BPM) on the dominant upper trapezius muscle in patients with bruxism. Although the Graston Technique is widely used, the specific impact of application speed on parameters such as muscle stiffness, muscle oxygenation, pressure pain threshold, and pain intensity remains under-investigated. By utilizing a crossover design with a 1-week washout period, this study allows for a precise within-subject comparison of the two speeds. The findings will clarify the optimal application frequency, providing objective data to guide the development of more effective, evidence-based manual therapy protocols for bruxism management.
Diagnosed with bruxism.
Aged 18-55 years.
Presence of trigger points in the trapezius muscle, according to the criteria defined by Travell and Simons.
Acute tears, tendon ruptures, or severe muscle injuries.
Conditions that prevent the application of the Graston Technique (e.g., skin lesions, open wounds, infections).
Having received botox injections in the temporomandibular joint (TMJ) region within the last 6 months.
Psychological disorders that may affect participation or measurements.
Crossover
Graston Technique 60 BPM
BehavioralGT1 and GT4 instruments will be applied using different strokes. To prepare the participant's tissue, the clinician will perform a light-intensity sweeping stroke with the GT1 instrument for 1 minute. Next, the tissue around the trigger points will be treated with a fanning stroke using the GT4 instrument for 2 minutes. Finally, the marked trigger points will be treated with a swivel stroke using the button end of the GT1 instrument for 2 minutes. During the application, the participant will sit upright with their arms resting on their thighs. The instruments will be applied at a 30 to 60-degree angle using multidirectional strokes. The application speed will be controlled using a metronome and performed at 60 beats per minute (BPM).
Graston Technique 120 BPM
BehavioralGT1 and GT4 instruments will be applied using different strokes. To prepare the participant's tissue, the clinician will perform a light-intensity sweeping stroke with the GT1 instrument for 1 minute. Next, the tissue around the trigger points will be treated with a fanning stroke using the GT4 instrument for 2 minutes. Finally, the marked trigger points will be treated with a swivel stroke using the button end of the GT1 instrument for 2 minutes. During the application, the participant will sit upright with their arms resting on their thighs. The instruments will be applied at a 30 to 60-degree angle using multidirectional strokes. The application speed will be controlled using a metronome and performed at 120 beats per minute (BPM).
Muscle stiffness
Shear Wave Elastography (SWE), an ultrasound-based imaging method, will be used to assess muscle stiffness in the participants. Ultrasonography will be performed using a high-resolution LOGIQ P10 device (ML6-15-RS; GE Healthcare Inc., Chicago, IL, USA). During the examination, L3-12 Hd and L8-18i linear probes will be used. To measure upper trapezius muscle stiffness, the ultrasound probe will be placed 2 cm lateral to the midpoint between the acromion of the scapula and the spinous process of the seventh cervical vertebra (C7). Measurements will be taken when several muscle fascicles are visible continuously along the imaging plane. Each measurement will be repeated three times for the assessed muscle, and stiffness parameters will be calculated quantitatively. The average of the three measurements will be recorded in meters per second (m/s).
Muscle oxygenation
Using near-infrared spectroscopy (NIRS) to evaluate trapezius muscle oxygen levels. Measurements will be performed both at rest and during muscle contraction. The measurement area will be shaved if necessary to prevent errors caused by hair. The area will then be cleaned with a cotton pad soaked in 70% alcohol solution. Participants will be seated with their feet flat on the floor, knees and hips flexed at 90°, and arms resting loosely on their thighs. For the upper trapezius muscle, the location of the probe will be determined as the midpoint of the line extending from the acromion to the spinous process of the C7 vertebra.
Pressure pain threshold
Pressure pain threshold (PPT) will be assessed using a digital algometer. The PPT, which measures peak force in Newtons, will be determined using a digital algometer consisting of a padded disc connected to a microprocessor-controlled unit (Lafayette Manual Muscle Test System™, Model 01163, Lafayette Instrument Company, Indiana, USA). The upper trapezius muscle's pressure pain threshold will be evaluated with this device. During the assessment, the researcher will place the algometer on the predetermined trigger points of the muscle, and the participant will verbally indicate when the sensation of pressure turns into pain. The applied pressure at that moment will be read from the digital display.
Pain intensity
Pain intensity will be assessed using the Visual Analog Scale (VAS), a 0-10 scale where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate greater pain intensity.
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