The group receiving dry needling combined with therapeutic exercise (n=35) will receive up to 6 sessions of stimulation at the active trigger points in the cervical region, according to Travell and Simons: occipitofrontalis, sternocleidomastoid, splenius capitis, anterior, middle, and posterior scalene muscles, upper, middle, and lower trapezius, and multifidus at the C6 level. Using ultrasound guidance, 0.25 mm x 25 mm needles will be inserted into the active. The needles will be connected to a TENS (transcutaneous electrical nerve stimulation) device (TensMed S82-Enraf Nonius), applying an asymmetric biphasic square wave current, low frequency (8 Hz), pulse duration of 250 μs, with an intensity perceived as mild to moderate, for 30 minutes. In addition, this group will undergo a protocol of specific therapeutic exercises for the cervical spine during the same electropuncture session and immediately afterward.

The therapeutic exercise group (n=35) will perform progressive exercises for the cervical flexor and extensor muscles, once a week for 6 weeks (6 sessions in total, with each session lasting 30 minutes). The protocol includes activation and recruitment of the deep cervical flexor muscles, isometric co-contraction exercises for both deep and superficial flexors, and eccentric and isokinetic exercises for both flexors and extensors. Each week's session will include the exercises for that week, along with the exercises from previous weeks, as detailed in the specific cervical spine exercise table, which indicates sets, repetitions, contraction time, and rest periods.

The group receiving dry needling combined with therapeutic exercise (n=35) will receive up to 6 sessions of stimulation at the active trigger points in the cervical region, according to Travell and Simons: occipitofrontalis, sternocleidomastoid, splenius capitis, anterior, middle, and posterior scalene muscles, upper, middle, and lower trapezius, and multifidus at the C6 level, bilaterally, once a week for 3 weeks. Using ultrasound guidance, 0.25 mm x 25 mm needles will be inserted into the active trigger points. The needles will be connected to a TENS (transcutaneous electrical nerve stimulation) device (TensMed S82-Enraf Nonius), applying an asymmetric biphasic square wave current, low frequency (2 Hz), pulse duration of 250 μs, for 30 minutes. In addition, this group will perform a protocol of specific therapeutic exercises for the cervical spine during the same electropuncture session and immediately afterward.

The neck disability index consists of 10 questions addressing functional activities such as personal care, lifting, reading, work, driving, sleeping, recreational, pain intensity, concentration and headache.

Pain will be assessed with the Visual Analog Scale (VAS), which assesses the pain intensity and degree of relief experienced by the patient (scored of 0 = no pain; 10 = unbearable pain).