Structural changes, including increased fat in the muscle and variable cross-sectional area (CSA), have been detected in the deep cervical extensors of the patients with chronic neck pain. Although exercise has shown efficacy in activation of the cervical flexors and in reducing pain, cervical extensors might be equally important for the management of chronic neck pain. Herein, although various studies have shown the efficacy of conventional isometric, Pilates and yoga exercises; data as regards the effects (and comparison) of these specific exercises on the cervical muscle morphology is insufficient or lacking. The aim of this study was to explore the clinical and morphological effects of isometric, yoga and Pilates exercises on neck muscles in patients with chronic neck pain. For this, ultrasound (US) imaging, which has proven to be a reliable, convenient, inexpensive