Electromyographic evaluation of free divers wearing realaxing bite

The objective of the project was to detect possible variations of the masticator muscolar tension in free divers wearing relaxing bite. The study was carried out by means of EMG evaluations performed before and after the use of the relaxing bite in order to verify its effectiveness in this specific sport. Materials and Methods - Four athletes were selected, two males and two females, of age between 23 and 39 with similar characteristics in terms of training typology and agonistic level. After an initial EMG exam, each athlete was given a bite to be worn only at night for the first three months (8 hours), and during night time and during training sessions for the following three months (more than 8 hours). In order to quantify the changes of masseter and temporalis muscles tension, two more sessions of surface EMG recordings were made during the period of use of the bite on a three monthly basis. Each session consisted of three registrations, two of them were associated with maximum voluntary contraction and in rest position respectively, while the third one was made in free diving condition for a maximum amount of time of two minutes for each individual. The latter exam allows to assess the impact of the hypoxia on the muscular condition (as it actually occurs during a sport performance) as well as to evaluate the impact of the relaxing bite on the muscular condition in order to validate its use in this particular sport. The EMG recordings were made according to the following scheme: in maximum voluntary contraction (the patient can breathe); in rest position (the patient can breathe); in free diving, emulation for a maximum amount of time of 2 minutes for each athlete. The second EMG recording (after three months of nightly bite application) and the third EMG recording (at the sixth month, after three months of bite application during night time and during sport trainings) were complemented with a fourth registration which was performed in apnea for a maximum amount of time of 2 minutes (as in the first test) while the athletics wearing the relaxing bite. Conclusion - Despite the unavoidable limits of the investigation due to the small size of the sample considered (because of the difficulty of finding homogeneous free divers not affected by TMD), such exams will allow us to assess the variations of EMG potentials in free divers wearing relaxing bites during breath as well as during free diving dry runs. Moreover, the results will provide us a consistent starting point to understand whether the use of bites during sport activity may increase muscular relax in the cranium-facial district, thus inducing enhanced agonistic performance