Research Problem: To know the immediate effects of high speed and low amplitude cervical manipulation on the electromyographic activity of the masseter muscles of physiotherapy students at the University of the Americas Course objective: To compare the immediate effects of high-speed, low-amplitude cervical manipulation on the electromyographic activity of the masseter muscles versus a placebo intervention in kinesiology students at the University of the Americas.

Specific objectives: To describe the changes in the electromyographic activity of the masseter muscles of the high-speed cervical manipulation group in students of the physiotherapy school of the University of the Americas of the Santiago Centro campus.

To describe the changes in the electromyographic activity of the masseter muscles of the placebo group in students of the physiotherapy school of the University of the Americas of the Santiago Centro campus.

Methodology: Single-blind, randomized clinical trial. Expected results: Significant differences are expected between the intervention group and the control group. This is reflected in a decrease in electromyographic activity in the masseter muscles after high-speed cervical manipulation.

Inclusion Criteria:

• Male and female physiotherapy students over 18 years of age who regularly attend face-to-face classes who have a mobility pass and a health declaration.
• Students who read and sign the informed consent.

Exclusion Criteria:

• Orthognathic surgery.

  • Recent head and neck injury or fracture (equal to or less than 3 months)
  • Dental or medical diagnosis of mandibular disorder or manifest facial pain.
  • Contraindication (red flag) to perform high speed and low amplitude cervical manipulation (bone cancer, osteoporosis, vertebral artery injury, etc.)