Non-specific neck pain (NSNP) is defined as pain not associated with neurological and specific pathologies in the posterior and lateral part of the neck between the superior nuchal line and the first thoracic vertebra. Many conservative treatment modalities including different exercise techniques are used in the treatment of NSNP. Therefore, the aim of our study was to investigate the effect of these techniques.

Non-specific neck pain (NSNP) is defined as pain not associated with neurological and specific pathologies (infection, fracture, inflammation, etc.) in the posterior and lateral part of the neck between the superior nuchal line and the first thoracic vertebra. Neglecting this pain can lead to muscle spasms, stiffness, and many other serious complications. Most neck pain is caused by trigger points in the cervicothoracic muscles. Trigger points cause the muscles to weaken, and neck pain with weak cervical muscles has a negative impact on a person's quality of life.

The estimated incidence of neck pain ranges from 10.4% to 21.3% each year and is affecting an increasing number of computer and office workers. Pain intensity is low in most new cases, but disabling neck pain develops in 0.6% of the population. Therefore, it is important to investigate which treatment modality is more effective in reducing neck pain and its symptoms. Some recent studies report evidence in favor of a particular type of exercise, while others report that there is no superior type or dose of exercise.

Neck pain recurs and develops within one to five years in 20% of patients and the rate of complete recovery in these cases is very low. Neck pain is the most frequently investigated musculoskeletal problem after low back pain. It is defined as non-specific neck pain due to multifactorial etiology. Many conservative treatment modalities are used in the treatment of NSNP. These include clinical exercises, medical treatments, neural therapy, manual therapy methods, massage, acupuncture, and various physical therapy modalities. Muscle energy techniques (MET) are manual therapy methods that involve soft tissue manipulation using precise and controlled, patient-initiated, isometric, and/or isotonic contractions to improve musculoskeletal function and reduce pain. MET can be used to mobilize a joint with a limited range of motion, lengthen a spastic or shortened muscle, reduce local edema, and strengthen a physiologically weak muscle or muscle group.

Post-isometric relaxation (PIR) is defined as a reduction in the tone of the agonist muscle after an isometric contraction. This technique aims to reduce muscle tension by regulating muscle function and is used to mobilize the restricted joint, reduce edema, and lengthen and strengthen muscles in both subacute and chronic conditions. Studies have also used PIR for neck pain.

The muscle spindle is one of the sensory receptors in skeletal muscle. Its function is to provide proprioceptive information to the cerebral cortex. As the muscle lengthens, the muscle spindle is activated, and a reflex contraction of the agonist muscle and relaxation of the antagonist muscle occurs. This process is known as reciprocal inhibition (RI). Studies using the RI technique in people with neck pain were found. However, no studies were found in people with non-specific neck pain.

Stretching is a general term describing a therapeutic maneuver used to increase the extensibility of soft tissues. Self-stretching (SS) is the self-application of this technique. Studies comparing the effects of MET with different treatment modalities in people with non-specific neck pain were identified in the literature. These trials found similar effects and varying degrees of superiority in reducing pain intensity and increasing range of motion (ROM). In the literature, studies have compared stretching with MET in people with neck pain or compared MET with different treatment methods and examined their effects on variables such as pain and ROM. However, no study was found that compared different METs and self-training in individuals with NSNP and investigated the immediate effect of EMG. Therefore, the aim of our study was to investigate the effect of these techniques. It was thought that the information obtained as a result of the study would guide the creation and development of rehabilitation programs.

The hypotheses of the study are as follows:

Hypothesis 1: The PIR technique applied to individuals with NSNP has a positive effect on pain intensity, pressure pain threshold, range of motion, and muscle activation.

Hypothesis 2: The RI technique applied to individuals with NSNP has a positive effect on pain intensity, pressure pain threshold, range of motion, and muscle activation.

Hypothesis 3: SS technique applied to individuals with NSNP has a positive effect on pain intensity, pressure pain threshold, range of motion, and muscle activation.

Hypothesis 4: Muscle energy techniques applied to individuals with NSNP have more positive effects on pain intensity, pressure pain threshold, range of motion and muscle activation than SS technique.

Inclusion Criteria:

• Being 18 years or older
• Being a volunteer to participate into the study
• Not having diagnosed orthopedic and neurological problems
• Having Neck pain for at least four months

Exclusion Criteria:

• Having diagnosed with active infectious pathology
• Having cervical spine fracture/previous cervical or thoracic surgery
• Having a history of severe trauma to the cervical spine
• Having a history of malignant tumors
• Having diagnosed with structural deformity
• Being used of a medical orthopaedic prosthesis
• Having a pacemaker
• Having diagnosed with disc prolapse