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The influence of mandibular stretching on athletes subjected to high intensity workout

D. Tonlorenzi, M. Conti, G. Traina


The use of oral appliances is considered effective in improving sport performance. Jaw clenching or stretching, improved breathing or positioning of the jaw have been proposed to explain the improvement. In this study, we reported the effects of regularly practiced mandibular stretching at submaximal opening of the jaw in Crossfit athletes. Seventeen test subjects undergoing mandibular stretching (MS) showed significantly reduced (p<0.001) performance time in a high-intensity workout measured before and after seven days of 10-minutes stretching practiced twice daily, while no improvement was observed in control subjects who did not perform the stretching. Additionally, blood lactate levels appeared to recover more quickly in MS subjects.
Crossfit is a type of training regimen that pushes the limits of bodily recovery processes. Jaw stretching, eliciting the trigeminocardiac reflex (a reflex decrease in heart rate and blood pressure following trigeminal stimulation) and central oxygen-conserving mechanisms could help relieve post-training stress and improve training recovery.


Mandibular stretching; CrossFit; Proprioceptive trigeminocardiac reflex; Oral splint; Training recovery

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Abdallah, E.F., Mehta, N.R., Forgione, A.G., & Clark, R.E. (2004) Affecting upper extremity strength by changing maxillo-mandibular vertical dimension in deep bite subjects. Cranio, 22, 268–275.

Abduljabbar, T., Mehta, N.R., Forgione, A.G., Clark, R.E., Kronman, J.H., Munsat, T.L., & George, P. (1997) Effect of increased maxillo-mandibular relationship on isometric strength in TMD patients with loss of vertical dimension of occlusion. Cranio, 15, 57–67.

Allen, C.R. (2019) Maximal Jaw Opening as a Method of Producing Concurrent Activation Po-tentiation. IJKSS, 7, 1.

Arent, S.M., McKenna, J., & Golem, D.L. (2010) Effects of a neuromuscular dentistry-designed mouthguard on muscular endurance and anaerobic power. Comparative Exercise Physiology, 7, 73–79.

Bailey, S.P., Willauer, T.J., Balilionis, G., Wilson, L.E., Salley, J.T., Bailey, E.K., & Strickland, T.L. (2015) Effects of an over-the-counter vented mouthguard on cardiorespiratory responses to exercise and physical agility. J Strength Cond Res, 29, 678–684.

Bergamini, M., Pierleoni, F., Gizdulich, A., & Bergamini, C. (2008) Dental occlusion and body posture: a surface EMG study. Cranio, 26, 25–32.

Bishop, P.A., Jones, E., & Woods, A.K. (2008) Recovery from training: a brief review: brief review. J Strength Cond Res, 22, 1015–1024.

Boroojerdi, B., Battaglia, F., Muellbacher, W., & Cohen, L.G. (2000) Voluntary teeth clenching facilitates human motor system excitability. Clin Neurophysiol, 111, 988–993.

Brunelli, M., Conti, M., Tonlorenzi, D., & Traina, G. (2020) Changes of sensory and pain thresholds in healthy subjects after mandibular extension at maximum mouth opening: implica-tions for temporomandibular disorders therapy. Arch Ital Biol, 158, 17–23.

Brunelli, M., Coppi, E., Tonlorenzi, D., Del Seppia, C., Lapi, D., Colantuoni, A., Scuri, R., & Ghione, S. (2012) Prolonged hypotensive and bradycardic effects of passive mandibular exten-sion: evidence in normal volunteers. Arch Ital Biol, 150, 231–237.

Ceneviz, C., Mehta, N.R., Forgione, A., Sands, M.J., Abdallah, E.F., Lobo Lobo, S., & Mavroudi, S. (2006) The immediate effect of changing mandibular position on the EMG activi-ty of the masseter, temporalis, sternocleidomastoid, and trapezius muscles. Cranio, 24, 237–244.

Chakfa, A.M., Mehta, N.R., Forgione, A.G., Al-Badawi, E.A., Lobo, S.L., & Zawawi, K.H. (2002) The effect of stepwise increases in vertical dimension of occlusion on isometric strength of cervical flexors and deltoid muscles in nonsymptomatic females. Cranio, 20, 264–273.

Chakravarthy, K., Chaudhry, H., Williams, K., & Christo, P.J. (2015) Review of the Uses of Vagal Nerve Stimulation in Chronic Pain Management. Curr Pain Headache Rep, 19, 54.

Chowdhury, T., Sandu, N., Sadr-Eshkevari, P., Meuwly, C., & Schaller, B. (2014) Trigemi-nocardiac reflex: current trends. Expert Rev Cardiovasc Ther, 12, 9–11.

Churei, H. (2003) [Relation between teeth clenching and grip force production characteristics]. Kokubyo Gakkai Zasshi, 70, 82–88.

Claudino, J.G., Gabbett, T.J., Bourgeois, F., Souza, H. de S., Miranda, R.C., Mezêncio, B., Soncin, R., Cardoso Filho, C.A., Bottaro, M., Hernandez, A.J., Amadio, A.C., & Serrão, J.C. (2018) CrossFit Overview: Systematic Review and Meta-analysis. Sports Med - Open, 4, 11.

Cole, C.R., Blackstone, E.H., Pashkow, F.J., Snader, C.E., & Lauer, M.S. (1999) Heart-rate re-covery immediately after exercise as a predictor of mortality. N Engl J Med, 341, 1351–1357.

D’Angelo, M., Zanfrini, S., Tonlorenzi, D., & Traina, G. (2014) The influence of mandibular stretching in athletes subjected to high intensity workout and in cyclists. Journal of Biotechnol-ogy, 185, S100.

de Oliveira, T.P., de Alvarenga Mattos, R., da Silva, R.B.F., Rezende, R.A., & de Lima, J.R.P. (2013) Absence of parasympathetic reactivation after maximal exercise. Clin Physiol Funct Im-aging, 33, 143–149.

Del Seppia, C., Ghione, S., Foresi, P., Lapi, D., Fommei, E., Colantuoni, A., & Scuri, R. (2017) Evidence in the human of a hypotensive and a bradycardic effect after mouth opening main-tained for 10 min. Eur J Appl Physiol, 117, 1485–1491.

Dudgeon, W.D., Buchanan, L.A., Strickland, A.E., Scheett, T.P., & Garner, D.P. (2017) Mouth-piece use during heavy resistance exercise affects serum cortisol and lactate. Cogent Medicine, 4, 1403728.

Dunn-Lewis, C., Luk, H.-Y., Comstock, B.A., Szivak, T.K., Hooper, D.R., Kupchak, B.R., Watts, A.M., Putney, B.J., Hydren, J.R., Volek, J.S., Denegar, C.R., & Kraemer, W.J. (2012) The effects of a customized over-the-counter mouth guard on neuromuscular force and power production in trained men and women. J Strength Cond Res, 26, 1085–1093.

Ebben, W.P. (2006) A brief review of concurrent activation potentiation: theoretical and practi-cal constructs. J Strength Cond Res, 20, 985–991.

Ebben, W.P., Flanagan, E.P., & Jensen, R.L. (2008) Jaw clenching results in concurrent activa-tion potentiation during the countermovement jump. J Strength Cond Res, 22, 1850–1854.

Forgione, A.G., Mehta, N.R., McQuade, C.F., & Westcott, W.L. (1992) Strength and bite, Part 2: Testing isometric strength using a MORA set to a functional criterion. Cranio, 10, 13–20.

Forgione, A.G., Mehta, N.R., & Westcott, W.L. (1991) Strength and bite, Part 1: An analytical review. Cranio, 9, 305–315.

Francis, K.T. & Brasher, J. (1991) Physiological effects of wearing mouthguards. Br J Sports Med, 25, 227–231.

Fry, A.C. & Kraemer, W.J. (1997) Resistance exercise overtraining and overreaching. Neuroen-docrine responses. Sports Med, 23, 106–129.

Furubayashi, T., Sugawara, K., Kasai, T., Hayashi, A., Hanajima, R., Shiio, Y., Iwata, N.K., & Ugawa, Y. (2003) Remote effects of self-paced teeth clenching on the excitability of hand mo-tor area. Exp Brain Res, 148, 261–265.

Gage, C.C., Huxel Bliven, K.C., Bay, R.C., Sturgill, J.S., & Park, J.H. (2015) Effects of mouthguards on vertical dimension, muscle activation, and athlete preference: a prospective cross-sectional study. Gen Dent, 63, 48–55.

Garner, D. & McDivitt, E. (2015) Effects of Mouthpiece Use on Lactate and Cortisol Levels During and After 30 Minutes of Treadmill Running. The Open Access Journal of Science and Technology, 3.

Garner, D.P. (2018) Oral Appliances and Athletic Performance. In Roettger, M. (ed), Modern Sports Dentistry, Textbooks in Contemporary Dentistry. Springer International Publishing, Cham, pp. 195–211.

Garner, D.P., Dudgeon, W.D., Scheett, T.P., & McDivitt, E.J. (2011) The effects of mouthpiece use on gas exchange parameters during steady-state exercise in college-aged men and women. J Am Dent Assoc, 142, 1041–1047.

Gelb, H., Mehta, N.R., & Forgione, A.G. (1996) The relationship between jaw posture and muscular strength in sports dentistry: a reappraisal. Cranio, 14, 320–325.

Glassman G. (2017) Understanding CrossFit. CrossFit Journal, Available at

Kandel, E.R. (2013) Principles of Neural Science, 5th ed. edn. McGraw-Hill, New York.

Laborde, S., Mosley, E., & Mertgen, A. (2018) Vagal Tank Theory: The Three Rs of Cardiac Vagal Control Functioning – Resting, Reactivity, and Recovery. Frontiers in Neuroscience, 12, 458.

Lapi, D., Federighi, G., Fantozzi, M.P., Seppia, C. del, Ghione, S., Colantuoni, A., & Scuri, R. (2014) Trigeminocardiac Reflex by Mandibular Extension on Rat Pial Microcirculation: Role of Nitric Oxide. PLOS ONE, 9, e115767.

Lazarov, N.E. (2000) The mesencephalic trigeminal nucleus in the cat. Adv Anat Embryol Cell Biol, 153, iii–xiv, 1–103.

Mazzeo, F., Monda, V., Santamaria, S., Nigro, E., Valenzano, A., Villano, I., Cibelli, G., Messi-na, A., & Messina, G. (2018) Antidoping program: an important factor in the promotion and protection of the integrity of sport and athlete’s health. J Sports Med Phys Fitness, 58, 1135–1145.

Miyahara, T., Hagiya, N., Ohyama, T., & Nakamura, Y. (1996) Modulation of human soleus H reflex in association with voluntary clenching of the teeth. J Neurophysiol, 76, 2033–2041.

Mor, A., Yılmaz, A.K., Acar, K., Birinci, M.C., & Ipekoglu, G. (2020) Does Nitric Oxide Intake Affect Post-Exercise Recovery in Athletes? A Study on Cocoa, Caffeine and Nitric Oxide Sup-plement: Effect of Nitric Oxide Intake in Athletes. Progress in Nutrition, 22, e2020007.

Rassaf, T., Lauer, T., Heiss, C., Balzer, J., Mangold, S., Leyendecker, T., Rottler, J., Drexhage, C., Meyer, C., & Kelm, M. (2007) Nitric oxide synthase-derived plasma nitrite predicts exer-cise capacity. Br J Sports Med, 41, 669–673; discussion 673.

Ruggiero, D.A., Ross, C.A., Kumada, M., & Reis, D.J. (1982) Reevaluation of projections from the mesencephalic trigeminal nucleus to the medulla and spinal cord: New projections. A com-bined retrograde and anterograde horseradish peroxidase study. Journal of Comparative Neu-rology, 206, 278–292.

Schaal, K., Le Meur, Y., Bieuzen, F., Petit, O., Hellard, P., Toussaint, J.-F., & Hausswirth, C. (2013) Effect of recovery mode on postexercise vagal reactivation in elite synchronized swim-mers. Appl Physiol Nutr Metab, 38, 126–133.

Schaller, B., Cornelius, J.F., Sandu, N., Ottaviani, G., & Perez-Pinzon, M.A. (2009) Oxygen-conserving reflexes of the brain: the current molecular knowledge. J Cell Mol Med, 13, 644–647.

Sforza, C., Tartaglia, G.M., Solimene, U., Morgun, V., Kaspranskiy, R.R., & Ferrario, V.F. (2006) Occlusion, sternocleidomastoid muscle activity, and body sway: a pilot study in male astronauts. Cranio, 24, 43–49.

Stanley, J., Peake, J.M., & Buchheit, M. (2013) Cardiac parasympathetic reactivation following exercise: implications for training prescription. Sports Med, 43, 1259–1277.

Stenger, J.M., Lawton, E.A., Wright, J.M., & Ricketts, J. (1987) Mouthguards: protection against shock to head, neck and teeth. Basal Facts, 9, 133–139.

Takahashi, T., Ueno, T., Taniguchi, H., Ohyama, T., & Nakamura, Y. (2001) Modulation of H reflex of pretibial and soleus muscles during mastication in humans. Muscle Nerve, 24, 1142–1148.

Tonlorenzi, D., Brunelli, M., Conti, M., Covani, U., & Traina, G. (2019a) An observational study of the effects of using an high oral splint on pain control. Arch Ital Biol, 157, 66–75.

Tonlorenzi, D., Conti, M., Giovannoni, F., Righini, G., Musetti, M., Costa, M., & Traina, G. (2019b) Training bradycardia increase in one elite cyclist following the use of a high oral splint [Paper presentation]. XXVIII Isokinetic Medical Group Conference, London, England.

Totzeck, M., Hendgen-Cotta, U.B., Rammos, C., Frommke, L.-M., Knackstedt, C., Predel, H.-G., Kelm, M., & Rassaf, T. (2012) Higher endogenous nitrite levels are associated with superi-or exercise capacity in highly trained athletes. Nitric Oxide, 27, 75–81.

Tsukimura, N. (1992) Study on the Relation between the Stomatognatic System and the Sys-temic Condition. Influences of Postural Changes in Vertical Maxillomandibular Relation on the Back Strength. Nihon Hotetsu Shika Gakkai Zasshi, 36, 705–719.



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