controversy remains about the stretching parameters needed to achieve a particular goal or treatment outcome. In clinical practice, multiple stretching techniques are used; nevertheless, there is no evidence-based agreement on the most effective parameters. One of these parameters, that might be affecting the treatment outcome the most, is the stretching duration, thus far there is a little agreement on the optimal stretching duration.

This non agreement in exact stretching parameters is obvious between authors and researchers in the field of muscle energy techniques (MET) as well as those who have used and advocate various durations for the passive stretch that follows the contraction phase in MET.

comparison and subsequent conclusions about appropriate stretching times are mainly based on mechanical factors such as range of motion and flexibility, while ignoring the neural adversative mechanical tension that may be created during stretching exercises. According to the literature , stretching induced neural tension may adversely affect the central nervous system and nerve root function due to the absence of the perineurium, which is the primary load carrying structure. Thus, safe or unsafe limits of nerve elongation are not well established, despite several basic scientific and clinical studies.. Consequently, in the present study, the current study aimed to answer the question: Is it theoretically possible, that increased longitudinal strain and stress on the spinal cord and nerve root from continuous stretching exercises may subtly impair the neural function? Our hypothesis is that a duration threshold exists where, once reached, adverse neural function will be apparent resulting in a reduction of either or both latency and amplitudes of evoked potentials.

Inclusion Criteria:

• Eligible patients had to be between 18 and 40 years of age
• have generalized neck pain for more than 3 months.
• with symptoms provoked by neck postures, movements, or palpation

Exclusion Criteria:

• Subjects' exclusion criteria included specific neck pain due to trauma, disc protrusion, whiplash, congenital deformity of the spine, spinal stenosis, neoplasm, inflammatory or rheumatic disease. Furthermore, subjects were excluded if they had a history of spine surgery and any objective findings consistent with neurological conditions and vascular disorders.

There is a plan to make individual participant data and related data dictionaries available

After 6 months and will become available for one year

not identified yet

The treating therapist, for both the control and intervention groups, was unblinded to the treatment method but the subjects and assessor who conducted the measurements were blinded. Assessor blinding was obtained through an independent research assist; not knowing the study design and not specifically involved in any aspect of the tria