Aerobic Physical Activity and Orofacial Myofascial Pain

Pain facilitation profile : masseter muscle

ΔTSP : Comparison of the Temporal Summation of Pain score (10th stimulation score minus 1st stimulation score) at the masseter muscle using calibrated pinprick stimuli (calibrated to induce a baseline pain of 20/100) between the 3 groups (TDM ; control group and sports group).

Temporal summation at the forearm muscle

Temporal summation (TS) will be assessed by applying repetitive stimuli in the form of blunt needle pricks (pinprick) to the skin overlying the forearm muscles. The intensity of the pinprick will be individually calibrated to induce a baseline pain of 20/100 on a Numerical Rating Scale (NRS). Participants will be asked to rate the intensity of the pain provoked by the pinprick. The examiner will first apply a single stimulus, followed by a series of 10 stimuli applied at a frequency of 1 Hz over an area of 1 cm². Pain will be assessed verbally using a numerical rating scale ranging from 0 to 100, with anchors at 0 ('no pain') and 100 ('worst imaginable pain'). The entire procedure will be repeated three times. For the pinprick stimulations, the magnitude of temporal summation (ΔTSP = pain score at the 10th stimulation - pain score at the 1st stimulation) will be calculated.

Referred sensations at the Masseter muscle

The assessment of referred sensation (RS) will be performed using mechanical stimulation. A force of 0.5 and 2.0 kg will be applied to the masseter muscle using a palpometer (Palpeter; Sunstar Suisse SA, Etoy, Switzerland). The stimulation will be repeated 5 times. Each individual mechanical stimulation will last 5 seconds, followed by a 10-second interval allowing the participant to rate the intensity of the sensation and report any RS. Mechanical sensitivity will be evaluated on an NRS scale of 0-50-100 (where 0 corresponds to no sensation, 1-49 to a non-painful sensation, 50 to the pain threshold, and 100 to the most painful sensation). Sensations will be considered referred if the participant reports a sensation extending beyond the boundary of the masseter muscle. If such a sensation occurs, the participant will be asked to point to the location where the sensation was felt, and the examiner will determine if this location lies outside the masseter muscle limits. If participants

Anxiety assessment

Anxiety will be assed by GAD-7 questionnaire ; a 7-item self-administered questionnaire used as a screening tool and a measure of the severity of generalized anxiety disorder. It calculates the score by assigning 0, 1, 2, or 3 points to the response options 'not at all', 'several days', 'more than half the days', and 'nearly every day', respectively. The total score for the GAD-7 questionnaire ranges from 0 to 21 points. If GAD-7 score is less than 4 : absence of anxiety, between 5 and 9 : mild anxiety, between 10 and 14 : moderate anxiety and superior than 15 : significant severe anxiety.

Depression assessment

Depression will be evaluated by PHQ-4 , a self-administered screening tool designed to score anxiety and depression, both of which are significant risk factors for the chronification of pain. The first two items assess anxiety, while the last two assess depression. Each item is scored from 0 to 3 (0 for 'not at all', 1 for 'several days', 2 for 'more than half the days', and 3 for 'nearly every day'). If PHQ-4 score is less than 2 : absence of psychological distress, between 3 and 5 : mild psychological distress, between 6 and 8 : moderate psychological distress and superior than 9 : psychological distress.