Aerobic Physical Activity and Orofacial Myofascial Pain

Orofacial myofascial pain, most commonly represented by Temporomandibular Disorders (TMD) a significant public health, affecting approximately 12% to 14% of the general population. These disorders are characterized by musculoskeletal pain in the masticatory muscles and joints, leading to reduced productivity and high socio-economic costs. Pathophysiological mechanisms are largely central in origin, similar to other chronic pain syndromes like fibromyalgia. Beyond pain, TMD severely impacts oral health-related quality of life by disrupting vital functions such as mastication and swallowing, and is frequently associated with accelerated dental structure loss due to clenching or grinding. While aerobic exercise is a recommended frontline treatment for many chronic pain conditions due to its ability to induce short-term hypoalgesia and long-term neuroplastic adaptations, it remains critically underutilized in the management of orofacial pain. This controlled clinical study aims to compare a pain neuromodulation mechanism (Temporal Summation of Pain) among patients suffering from chronic orofacial myofascial pain, inactive healthy individuals, and healthy individuals practicing endurance sports. Furthermore, investigating Endogenous Pain Modulation (EPM) in pain-free populations allows for a better understanding of how physical activity modulates pain pathways by eliminating confounding factors associated with pre-existing painful conditions. This knowledge will help clarify how aerobic exercise can be utilized within preventive and therapeutic strategies for the management of orofacial myofascial pain. Moreover, it will facilitate the identification of efficacy markers for therapies such as exercise rehabilitation and physical activity.

Inclusion Criteria: For all participants: * Must be of legal age (18 years or older). * Must be fully informed of the study constraints and have provided written informed consent. * Must be registered with a social security scheme. TMD-M Group (Orofacial Myofascial Pain): • Diagnosis of painful Temporomandibular Disorder (TMD) according to the DC/TMD (Diagnostic Criteria for TMD) clinical standards. Athletic Group (Active Healthy Subjects): • Engagement in a minimum of 3 hours of endurance training per week. This threshold is set in accordance with evidence-based WHO recommendations for adults, stating that at least 30 minutes of regular moderate-intensity physical activity per day reduces the risk of multiple diseases. Control Group (Inactive Healthy Subjects) : * Absence of TMD. * Absence of regular aerobic physical activity. Exclusion Criteria: * Presence of chronic pain outside of TMD (temporomandibular joint disorder) * Patient under legal guardianship (guardianship, conservatorship) * Refusal to participate * Uncooperative patients, who do not speak or read French fluently, are unable to understand the principle of a pain scale, and are unable to cooperate with the tests. * Pregnant women