Background The mechanisms behind non-specific neck pain (NS-NP) have not yet been fully clarified. The anatomic relation between the tongue and structures that attach to the cervical spine suggests a possible clinical relation with a NS-NP.

This study protocol describes a randomized, double-blind, clinical trial, the aim of which is to determine the influence of the release of the tongue muscles on pain intensity, cervical range of motion and neck function in individuals with NS-NP.

Methods/Design Forty patients with NS-NP will be enrolled in a randomized, double-blind, clinical trial. The participants will be randomly allocated to two groups of 20 patients each. The experimental group (EG) will be submitted to a clinical method considered the gold standard for the treatment of neck pain together with a tongue muscle release protocol. The control group (CG) will only receive the gold standard method for the treatment of neck pain. All patients will receive six sessions of treatment at a frequency of twice per week and will be evaluated before and one week after the end of treatment. The primary outcome will be pain intensity measured using a numerical pain rating scale (range: 0 [no pain] to 10 [maximum pain]). The secondary outcomes will be the Pain Catastrophizing Scale, Patient-Specific Functional Scale, Neck Disability Index and cervical range of motion. Comparisons between groups before and after treatment will demonstrate whether the tongue muscle release technique exerts an effect on pain intensity, cervical range of motion and neck function in individuals with NS-NP.

Discussion The purpose of this randomized clinical trial is to evaluate the effect of a tongue muscle release technique on pain intensity, cervical range of motion and neck function in patients with NS-NP. The data will be published after the study is completed. The study will support the practice of evidence-based physical therapy for individuals with nonspecific neck pain.

Inclusion Criteria:

• History of neck pain for a period of more than three months; score of 10 to 24 on the Neck Disability Index (adapted and validated for the Brazilian population); score of 3 to 6 points on numerical rating scale (NRS) for perceived pain intensity.

Exclusion Criteria:

• History of neurological disorders (irradiated pain) or neck surgery; chronic neck pain resulting from a traumatic incident (whiplash); chronic musculoskeletal condition (such as muscular disorder or polyarthritis); fibromyalgia; systemic disease; current pregnancy; having undergone physical therapy, massage or acupuncture in the previous two weeks; or use of analgesic, muscle relaxant, psychotropic agent or anti-inflammatory agent in the previous three days.