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Relation between Teeth Clenching and Grip Force Production Characteristics.
Abstract
This study investigated the possible contributing effect of oral motor function on maximal and explosive grip force production characteristics. Fourteen healthy male subjects (age 22.5 +/- 2.1 years) were asked to exert maximal explosive grip strength with their dominant hands under the following four conditions: 1. Teeth clenching before and during grip strength exertion (C-C), 2. Teeth clenching before grip strength exertion and mandibular resting position during grip strength exertion (C-R), 3. Mandibular resting position before grip strength exertion and teeth clenching during grip strength exertion (R-C), and 4. Mandibular resting position before and during grip strength exertion (R-R). Maximal force (maxF), average force for every 0.1 s (aveF), maximal rate of force development (maxRFD) and time required to reach 90% of maxF (T 90% max) were analyzed for 1 s from the onset of grip force production. MaxF under C-C and R-C were significantly greater than that under R-R by 12.1% and 12.3%, respectively. AveF under C-C was significantly greater by 10.0-41.2% than that under R-R for all ten periods. AveF under C-R was significantly larger by 9.8-19.0% than that under R-R conditions from 0 to 0.4 s. Compared with under R-R conditions, maxRFD under C-C and C-R increased by 15.8% and 8.5%, respectively, and T 90% max under C-C, C-R and R-C decreased by 22.3%, 12.3% and 12.8%, respectively. These findings suggest that oral motor functions such as teeth clenching may influence not only maximal grip strength generation but also the rapidity of grip force production.
... However, numerous studies have demonstrated performance-enhancing effects when mouthguards are worn [2,6,13,21,34,[37][38][39]. Some authors have suspected that performance improvements can be achieved when wearing an mouthguard compared to without [3,6,9,13,16,34,37,38]. Referring to the research of Ebben et al. [15,16], the majority of authors promote the mouthguard-induced concept of concurrent activation potentiation (CAP) [2,3,6,9,13,34,38]. ...
... Some authors have suspected that performance improvements can be achieved when wearing an mouthguard compared to without [3,6,9,13,16,34,37,38]. Referring to the research of Ebben et al. [15,16], the majority of authors promote the mouthguard-induced concept of concurrent activation potentiation (CAP) [2,3,6,9,13,34,38]. The CAP mechanism has a spectrum of theoretical backgrounds associated with potentiation-phenomenon mechanisms [14] and with intercortical communication behavior [11]. ...
... Recent studies, on the other hand, have suggested that increased clenching force through remote voluntary contraction (RVC) may lead to forcing concurrent activation potentiation (CAP) to occur-thus improving an athlete's motor performance when wearing an mouthguard [1,2,5,6,9,38]. Busca et al. [5] demonstrated a significantly higher power and jump height in a CMVJa with a customized mouthguard. The present results show neither a significantly increased jump height nor a significantly improved muscle activation (Σ). ...
Background
Some studies have suggested that a mouthguard is a performance-enhancing device due to a remote voluntary contraction. The extent to which a mouthguard can induce this phenomenon, e.g., by potentially increasing biting, has not been clarified. This study’s aim was to investigate the muscular activity of the maxillary and peripheral musculature and motor performance during a rest and exercise test.
Methods
Our study comprised 12 active, male, professional young handball players (age 18.83 ± 0.39 years). Their performance, electromyographic (EMG) muscle activity ( Σ ), and lateral deviation ( Δ ) of the masticatory and peripheral musculature were measured during rest in a maximum bite force measurement, one-legged stand, a kettlebell swing exercise and a jump test while wearing a customized mouthguard (CMG) or not wearing one (Co).
Results
Maximum bite force measurements did not differ significantly in their mean values of muscle activity ( Σ ) for the masseter and temporalis muscles (Co 647.6 ± 212.8 µV vs. CMG 724.3 ± 257.1 µV p = 0.08) (Co 457.2 ± 135.5 µV vs. CMG 426.6 ± 169.3 µV p = 0.38) with versus without CMG. We found no differences in the mean activation values during a one-legged stand, the kettlebell swing, and jump test ( Σ ) in any of the muscles tested. Lateral deviations ( Δ ) wearing a CMG were significantly less in the erector spinae during the kettlebell swing (Co 5.33 ± 3.4 µV vs. CMG 2.53 ± 1.8 µV p = 0.01) and countermovement jump (Co 37.90 ± 30.6 µV vs. CMG 17.83 ± 22.3 µV p = 0.03) compared to the performance without a CMG. Jump height, rotation moment, and balance were unchanged with versus without CMG.
Conclusion
Our results at rest and during specific motor stress show no differences with or without a CMG. The improved peripheral muscular balance while wearing a CMG indicates improved muscular stabilization.
... T here is a growing body of research demonstrating a relationship between jaw clenching and improvements in force production performance variables during a variety exercise modalities (2,(9)(10)(11)13,15,16). Examples of jaw clenching positively impacting performance include significant increases in force production and rate of force development (RFD) during grip strength assessment (15), improvements in RFD as well as time to peak force (PF) during vertical jump assessment (9), and increased muscle activation during vertical jump (2) and isometric knee extension (13). ...
... T here is a growing body of research demonstrating a relationship between jaw clenching and improvements in force production performance variables during a variety exercise modalities (2,(9)(10)(11)13,15,16). Examples of jaw clenching positively impacting performance include significant increases in force production and rate of force development (RFD) during grip strength assessment (15), improvements in RFD as well as time to peak force (PF) during vertical jump assessment (9), and increased muscle activation during vertical jump (2) and isometric knee extension (13). ...
... Clenching the jaw, gripping with the fists, and the Valsalva maneuver all have potential to elicit a phenomenon known as concurrent activation potentiation (CAP) (9)(10)(11). The principle behind CAP has been demonstrated in several recent studies (2,(9)(10)(11)13,15,16) but was first used to describe the ergogenic advantage of increased force production of a muscle group attained through the use of RVCs simultaneously with prime mover activation. ...
This study examined the effects of jaw clenching, and a self-adapted, jaw repositioning mouthpiece on force production during maximum countermovement vertical jump and maximum isometric mid-thigh clean pull assessments in an attempt to determine any ergogenic effects attributable to clenching, jaw repositioning mouthpiece use, or the combination of both. Thirty-six male subjects performed vertical jump and isometric clean pull assessments from a force platform under various mouthpiece and clench conditions. A 3x2 (mouthpiece x clench) repeated measures ANOVA was conducted to analyze each of the following force production variables for both assessments: peak force, normalized peak force, and rate of force development. Additionally, jump height was analyzed for the vertical jump. Results revealed improvements in peak force (F1,35 = 15.84, p < 0.001, ηp= 0.31), normalized peak force (F1,35 = 16.28, p < 0.001, ηp= 0.32), and rate of force development (F1,35 = 12.89, p = 0.001, ηp= 0.27) during the isometric clean pull assessment when participants maximally clenched their jaw, regardless of mouthpiece condition. There were no statistically significant differences in jump height, peak force, normalized peak force, or rate of force development during the vertical jump for any treatment condition. This study supports previous research demonstrating that the implementation of remote voluntary contractions such as jaw clenching can lead to concurrent activation potentiation and a resulting ergogenic effect during activities involving and requiring high force production.
... This methodological approach comprises components of postural control, muscular strength and reaction time. As clenching of the jaw was shown to significantly improve reflex facilitation (Miyahara et al., 1996;Takada et al., 2000), static postural control (Hellmann et al., 2011(Hellmann et al., , 2015Ringhof et al., 2015b), force production, and rate of force development (Forgione et al., 1991;Hiroshi, 2003;Ebben et al., 2008), it was hypothesized that submaximum biting would lead to improved balance recovery in terms of increased dynamic stability. We also hypothesized a concomitant decrease in joint flexion angles of the knee and hip of the recovery limb at touchdown as well as during the subsequent stance phase. ...
... significantly influence recovery behavior of healthy young adults with regard to the variables under investigation. Previous studies on the impact of concurrent jaw clenching activities observed significant improvements in peak force and rate of force development as compared to non-clenching controls (Forgione et al., 1991;Hiroshi, 2003;Ebben et al., 2008). Further, significant reductions in CoP displacements have been described under static conditions (Hellmann et al., 2011;Ringhof et al., 2015b). ...
... Clenching the jaw, hence, seems to be part of a common physiological repertoire used to improve the neural drive to distal body segments and, by this means, to enhance performance in many ways (Ebben, 2006;Ringhof et al., 2015a). This, in turn, would suggest that many studies focusing the ergogenic effects of jaw clenching actually did not observe performance improvements when the jaw was clenched, but rather a decrease in the non-clenching condition (Hiroshi, 2003;Ebben et al., 2008). ...
Postural control is crucial for most tasks of daily living, delineating postural orientation and balance, with its main goal of fall prevention. Nevertheless, falls are common events and have been associated with deficits in muscle strength and dynamic stability. Recent studies reported on improvements in rate of force development and static postural control evoked by jaw clenching activities, potentially induced by facilitation of human motor system excitability. However, there are no studies describing the effects on dynamic stability. The present study, therefore, aimed investigated the effects of submaximum jaw clenching on recovery behavior from forward loss of balance. Participants were twelve healthy young adults, who were instructed to recover balance from a simulated forward fall by taking a single step while either biting at a submaximum force or keeping the mandible at rest. Bite forces were measured by means of hydrostatic splints, whereas a 3D motion capture system was used to analyze spatiotemporal parameters and joint angles, respectively. Additionally, dynamic stability was quantified by the extrapolated CoM concept, designed to determine postural stability in dynamic situations. Paired t-tests revealed that submaximum biting did not significantly influence recovery behavior with respect to any variable under investigation. Therefore, reductions in postural sway evoked by submaximum biting are obviously not transferable to dynamic stability. It is suggested that these contradictions are the result of different motor demands associated with the abovementioned tasks. Furthermore, floor effects and the sample size might be discussed as potential reasons for the absence of significances. Notwithstanding this, the present study also revealed that bite forces under both conditions significantly increased from subjects’ release to touchdown of the recovery limb. Clenching the jaw, hence, seems to be part of a common physiological repertoire used to improve motor performance.
... More precisely, decay of center of pressure displacements induced by submaximum biting has been revealed by posturographic analysis (Hellmann et al., 2011b;Ringhof et al., 2015). Similar to the stabilizing effects, significant increases in force production and rate of force development when clenching the jaw have been described (Forgione et al., 1991;Hiroshi, 2003;Ebben et al., 2008). Ebben et al. (2008) suggested that the effects were caused by concurrent activation potentiation which, in turn, enhanced the neural drive. ...
... Ergogenic effects on muscle strength and power have also been described for jaw-clenching tasks. When the jaw was clenched, Hiroshi (2003) and Ebben et al. (2008) observed significant increases in peak force and rate of force development during grip strength assessments and countermovement jumps, respectively. The latter authors suggested that these improvements were provoked by concurrent activation potentiation, which increased the neural drive to the skeletal muscles, thus, gaining the athlete an ergogenic advantage during strength-related motor tasks (Ebben et al., 2008). ...
... The last, and probably most conclusive, factor to be considered is that the abovementioned research on the impact of jaw clenching on muscular force development used an open mouth, non-clenching condition as control (Hiroshi, 2003;Ebben et al., 2008). Specifically, the participants in the investigations of Hiroshi (2003) and Ebben et al. (2008) were instructed to clench their jaw to the maximum extent or to keep their mouth open while performing the grip strength tests and countermovement jumps, respectively. ...
Human motor control is based on complex sensorimotor processes. Recent research has shown that neuromuscular activity of the craniomandibular system (CMS) might affect human motor control. In particular, improvements in postural stability and muscle strength have been observed as a result of voluntary jaw clenching. Potential benefits of jaw aligning appliances on muscle strength and golf performance have also been described. These reports are highly contradictory, however, and the oral motor task performed is often unclear. The purpose of our study was, therefore, to investigate the effect of submaximum biting on golf performance via shot precision and shot length over three different distances. Participants were 14 male professional golfers – seven with sleep bruxism and seven without – randomly performing golf shots over 60 m, 160 m, or driving distance while either biting on an oral splint or biting on their teeth; habitual jaw position served as the control condition. Statistical analysis revealed that oral motor activity did not systematically affect golf performance in respect of shot precision or shot length for 60 m, 160 m, or driving distance. These findings were reinforced by impact variables such as club head speed and ball speed, which were also not indicative of significant effects. The results thus showed that the strength improvements and stabilizing effects described previously are, apparently, not transferable to such coordination-demanding sports as golf. This could be due to the divergent motor demands associated with postural control and muscle strength on the one hand and the complex coordination of a golf swing on the other. Interestingly, subjects without sleep bruxism performed significantly better at the short distance (60 m) than those with bruxism. Because of the multifactorial etiology of parafunctional CMS activity, conclusions about the need for dental treatment to improve sports performance are, however, completely unwarranted.
... Przyczyn otrzymanych wyników można doszukiwać się w czynnikach mechanicznych oraz psychologicznych. Jak wyżej wspomniano, zaciskanie zębów, będące istotą bruksizmu, jest także sposobem na poprawę kontroli motorycznej narządu ruchu, stabilizacji posturalnej oraz skutkuje wzrostem zdolności generowania siły maksymalnej [19,25,26]. Jako, że na wyniki we wspinaczce sportowej wpływają takie umiejętności fizyczne, jak siła i moc kończyn górnych, zaciskanie zębów może stanowić próbę zwiększenia tych parametrów [15,27]. ...
... The reasons for the results obtained can be found in the mechanical and psychological factors. As mentioned above, tooth clenching, which is the essence of bruxism, is also a way to improve motor control of the musculoskeletal system, postural stabilization, and results in an increase in the ability to generate maximum force [19,25,26]. As the results in sports climbing are influenced by physical skills such as strength and power of the upper limbs, gritting the teeth may be an attempt to increase these parameters [15,27]. ...
Background. The consequences of the COVID-19 pandemic include the emergence or intensification of negative emotional states, such as anxiety disorders or depression. The deterioration of the emotional state in human population can be explained by the severe increase in the level of psychological stress related to the pandemic. In turn, mental stress can lead to the appearance or exacerbation of psychosomatic symptoms. Mental stress is one of the risk factors for bruxism. Due to the current pandemic situation, there is an increase in the frequency of bruxism symptoms in the population. The aim of this study was to analyze the occurrence of bruxism symptoms in sports climbers during the COVID-19 pandemic. Material and methods. The study consisted of two stages - the first one was carried out in August 2019 and the second one was repeated in May 2020, three months after the national quarantine in Poland had been announced . 67 people in the control group and 67 in the studied group were qualified for the study. The occurrence of awake and sleep bruxism was determined using a questionnaire. Results. The collective analysis showed that the studied group had a lower percentage of respondents with awake bruxism compared to the control group - the results reached the required threshold of statistical significance. The prevalence of sleep bruxism between the groups was similar - the differences did not reach the assumed significance threshold. Conclusions. The level of bruxism symptoms among climbers was significantly lower during the COVID-19 pandemic than before it. The obtained results and possible adaptation mechanisms in climbers require further analysis.
... On the other hand, teeth clenching can cause an increase in some physical parameters, such as, e.g., muscle activity and force production [11]. This fact may suggest that in athletes practicing strength sports changes can be observed in the bioelectric potentials of the masticatory muscles. ...
... Moreover, in this study, increased clamping force was associated with the activation of relevant parts of the cerebral cortex in response to the clenching of teeth [21]. Churei's research, on the other hand, reports that the motor functions of the stomatognathic system, such as clenching teeth, not only increase the maximum gripping force, but also the speed of gripping force [11]. According to the literature on the subject, the impact of the neuromuscular activity of the stomatognathic system also affects motor control of movement and an increase in postural stability [22]. ...
Masticatory muscle activity during teeth clenching is associated with changes in many physiological parameters throughout the body. Clenching can improve muscle activity, force production, rate of force development, and joint fixation. Hence, teeth clenching and masticatory muscle activity can be important in competitive sports activities. Sport climbing is becoming increasingly popular and will be included for the first time in the Summer Olympic Games, Tokyo, 2020. However, masticatory muscle activity in sport climbers has not yet been studied. The aim of the presented study is to compare the bioelectrical activity of the masticatory muscles in sport climbers and non-climbers in order to determine the relationship between these muscles and climbing activity. 44 subjects without masticatory system disorders (16 women and 28 men, average age 26.3) were divided into two groups of 22 sport climbers (8 women, 14 men, climbing experience >4 years), while 22 people (8 women, 14 men, with no regular sports activity) were assigned to the control group. Electromyographic examination of temporalis anterior (TA) and masseter muscle (MM) was evaluated in three conditions: during resting mandibular position, during maximum intercuspation clenching, and during maximum voluntary clenching with cotton rolls between teeth. For statistical analysis, the W Shapiro-Wilk test and the Mann-Whitney U test were used. Sport climbers showed significantly higher bioelectrical activities of MM during maximum intercuspation clenching (238.45 µV vs. 83.87 µV, p = 0.002), and during maximum voluntary clenching with cotton rolls between teeth (300.01 µV vs. 101.38 µV, p = 0.001) compared to controls. The differences between groups in relation to the resting bioelectrical activity of the MM muscles, and TA muscles in all conditions were not statistically significant (p > 0.05). Higher bioelectrical activity of masseter muscles during clenching in climbers can be associated with this sports activity. However, the mechanism remains unknown and requires future research.
... Le paramètre mesuré est la puissance maximale (Peak Power, PP). Des études montrent que le port d'un protège-dents de performance permet d'augmenter le PP mais aussi de l'atteindre plus rapidement et de le maintenir plus longtemps [9,17,18]. Cependant des résultats contraires ont également été publiés [19,20]. Les différences de résultats obtenus entre les études en termes d'amélioration de la résistance chez les porteurs de protège-dents soulignent l'inhomogénéité de ces études notamment parce qu'elles portent sur des exercices physiques très différents. ...
... Plusieurs études ont confirmé l'effet neuromusculaire de l'activité motrice orale et des différentes positions de la mandibule sur le contrôle postural [50]. Des études suggèrent que l'augmentation de la force musculaire lors du serrement des dents serait la conséquence du concurrent activation potentiation ou en français la « potentialisation par activation simultanée » qui optimiserait la commande descendante [18,19,51]. Le principe de cette potentialisation est que la force d'un muscle A devient plus importante si les muscles B (les muscles masticateurs par exemple) sont contractés en même temps. ...
Introduction: Since their appearance in the 1890s, mouthguards have been the subject of numerous research studies. Based on the results of these studies, the use of mouthguard is recommended for the prevention of orofacial lesions in some sports. Since the mid-1960, a new type of mouthguard appeared: the performance mouthguard. According to its manufacturers and creators, this appliance particularly enables to improve endurance, strength, muscular power, reaction time, precision of movements, recovery capacity, range of motion, concentration and proprioception, and to decrease fatigue and stress.
Literature review: A review of 50 years of medical research on performance mouthguards shows contradictory results. This reflects the inhomogeneity of studies which focus on different mouthguards, parameters recorded, muscular groups and sports.
Conclusion: At the moment, the enhancement of performance by using a mouthguard is an assumption. However, the latest blinded controlled clinical trials tend to validate this assumption. Harmonization of research protocols would allow this assumption to become evidence.
... Recent research examined the effect of CAP on isometric strength. Hiroshi studied the effects of different concurrent jaw clenching maneuvers before and/or during a handgrip maximal voluntary contraction (29). The author found a significant 12% increase in maximal force with the 2 conditions when jaw clenching was concurrently performed. ...
... Benefits were observed in both handgrip and BRW when comparing the 3 conditions used in this study (i.e., no jaw clenching, jaw clenching, and jaw clenching with mouthpiece). According to Hiroshi, statistically significant improvements were found when the subjects performed the handgrip test while clenching their jaw (JAW and MP, in this study) with respect to NON-JAW (29). In this respect, the H-reflexes' facilitation of the forearm muscles during a voluntary jaw clenching could explain the differences found in the handgrip test (40). ...
Recent studies have investigated the ergogenic effects of different types of mouthguards. There is evidence of the benefits of clenching customized mouthpieces on force and power development. The phenomenon called concurrent activation potentiation (CAP) promoted in jaw clenching seems to enhance the muscular strength and power in maximal isometric contractions and powerful actions in sport. Moreover, a bite-aligning mouthpiece may promote a more aligned and powerful clench. The objective of the present study was to investigate the effects of jaw clenching while wearing a customized bite-aligning mouthpiece (MP) on jump ability and isometric maximal strength tests in contrast to two other conditions: non-jaw clenching (NON-JAW) and jaw clenching without the mouthpiece (JAW). A within-subjects design was used to assess the jump performance and the maximal isometric force in 28 physically-active male subjects. Statistical analysis revealed significantly higher performance in JAW and NON-JAW conditions for handgrip force (HG-peakforce) as well as all variables of the back-row exercise (BRW) and countermovement vertical jump (CMVJ) (p<=0.05). Significant differences between NON-JAW and JAW were found for HG-peakforce (p<=0.05). These findings suggest that it is advisable to use a customized bite-aligning mouthpiece to improve strength and power performance.
... It has been reported that jaw position affects biceps brachii muscle endurance time, forearm muscle motor activity, isometric strength during shoulder abduction, and deltoid muscle isometric strength (Abdallah et al., 2004;Ferrario et al., 2001;Takahashi et al., 2003;Wang et al., 1996). Churei et al. demonstrated that jaw clenching increased grip strength (Churei, 2003). These studies appear to evaluate isometric strength and endurance, and the results can be explained by the facilitation of Hreflexes during jaw clenching (Takahashi et al., 2003). ...
The jaw sensorimotor system has functional relationships with other parts of the body through neuroanatomical and biomechanical interactions. The aim of this study was to examine the effects of different jaw positions on upper extremity performance, core endurance, and postural stability. This cross-sectional study included 49 healthy young adults aged 18-28 years. Upper extremity performance was evaluated using the push-up test, core endurance was evaluated using the McGill’s Trunk Flexion and Extension Test and postural stability was evaluated using the Balance Error Scoring System. All assessments were made with resting jaw and clenching jaw positions. There was no significant difference in the Push-up test and Balance Error Scoring System scores in different jaw positions (p>0.05). The Mcgill trunk flexion test and extension test performance were found to be better in the clenched jaw position (p=0.017, p=0.035, respectively). The results of this study showed that jaw clenching increases core endurance time. This result should be taken into account when planning an evaluation and rehabilitation program for the core area.
... Th e similar facilitation of H-refl ex induced by teeth clenching has been found in the forearm muscles [14]. Hiroshi [7] reported that teeth clenching before and during hand griping elicits a signifi cant increase of maximal force and rate of force development as compared with no clenching conditions. Furthermore, a number of studies evaluated the potentiation eff ect of RVC combined with the performance of various speed-strength exercises, termed Concurrent Activation Potentiation (CAP) [2]. ...
Concurrent activation potentiation (CAP) is recently developed method for enhancing athletic performance in speed-strength exercises. Th is phenomenon is based on the stimulatory eff ect of the voluntary contraction of remote mus-cles, which facilitates activation of prime movers and synergists for targeted exercise. Physiological prerequisites for this ergogenic eff ect are associated with the integrative function of the cerebral motor cortex and increased excit-ability of spinal motor neurons. Th e present study was aimed at evaluating the ergogenic eff ect producing by CAP treatment on the performance of the race start in competitive swimming. Th e CAP modifi ed start technique presupposed the teeth clenching and voluntary contraction of abdominal muscles aft er the preliminary starting command. Eight elite and sub-elite swimmers executed four crawl stroke starts: two CAP modifi ed and two conventional trials with objective registration of start reaction and time to complete a 15-m segment. Statistical analysis included a repeated measures two-way ANOVA test and size eff ect. Both the p-value and d-value between experimental and control sets were calculated. Th e average benefi t of the CAP modifi ed technique was equal to 0.08 s, which includes an advantage in start reaction equal to 0.05 s. As a result, application of the CAP modifi ed technique to swimming race start resulted in a signifi cant ergogenic eff ect, which was evaluated by start reaction and performance time on the 15-m segment of distance.
INTRODUÇÃO: O levantamento de peso tem sido associado ao hábito do apertamento dentário e, consequentemente, à predisposição de disfunção temporomandibular (DTM). Mesmo o CrossFit® sendo uma modalidade que trabalha com levantamento de peso, não foram encontrados artigos que investigaram a DTM em seus praticantes. OBJETIVO: Estimar a frequência e severidade dos sintomas de disfunções temporomandibulares em praticantes de CrossFit® e verificar se há relação com a participação em competições ou o tempo de prática da modalidade. MATERIAIS E MÉTODOS: Estudo transversal realizado nos três boxes de CrossFit® existentes no município de Jaú/SP. Praticantes pertencentes ao sexo masculino, com idade entre 20 e 40 anos, foram avaliados utilizando-se o Índice Anamnésico de Fonseca. As variáveis de desfecho foram o escore de sintomas e grau de severidade da DTM, além da participação em competições e o tempo de prática da modalidade. Houve aprovação da pesquisa pelo Comitê de Ética das Faculdades Integradas de Jaú (CAAE 91712418.3.0000.5427). RESULTADOS: Dos 52 participantes da pesquisa, 40,4% possuem sintomas de DTM. Desses, 38,4% de grau leve e 2,0% de grau moderado. Não foi encontrada diferença estatística comparando-se o tempo de prática ou competidores e não competidores. CONCLUSÃO: A frequência de sintomas de DTM em praticantes de CrossFit é de 40,4%. O grau de severidade predominante foi o leve. Não foi encontrada relação entre o aumento da frequência e o tempo de prática da modalidade ou o fato de ser competidor.
Introdução: O uso de protetores bucais (PB) na prática de esportes tem sido de enorme importância para a prevenção de traumas bucais. No entanto, atletas hesitam em usar protetores bucais por causa da redução no desempenho. Objetivo: Avaliar a influência aguda do uso de diferentes protetores bucais na capacidade cardiorrespiratória, potência muscular e metabólica em atleta de basquetebol profissional. Método: Foi realizado um estudo randomizado cruzado: sem protetor bucal (Controle), protetor bucal universal (PBU) e protetor bucal personalizado (PBP). O atleta realizou 2 baterias de teste constituído por 30 saltos verticais. Os saltos verticais foram realizados antes (AN) e imediatamente após (IA) a execução do teste da capacidade cardiorrespiratória (YO-YO Intermittent Recovery). Foi analisada a concentração de lactato sanguíneo AN e IA a execução dos dois protocolos. Resultado: O presente estudo evidencia de forma descritiva que o uso do PBP pode impactar no aumento da distância máxima percorrida pelo atleta, que consequentemente pode ter elevado à concentração de lactato sanguíneo. Já a manutenção da potência muscular foi similar entre os ensaios experimentais. Conclusão: Estes achados fornecem evidências adicionais para treinadores que defendem o uso de protetores bucais personalizados, não só para proteção orofacial, mas também na indução de modificações positivas em determinados parâmetros específicos como a capacidade cardiorrespiratória e metabólica do atleta de basquetebol classificado como respirador nasal.
Background: In contact sports, such as martial arts, protection from oral injuries is generally recommended. Several authors have focused on the effects of wearing such oral protective gear on sports performances and, in particular, occlusal devices. Although many studies have shown improvements in athletic performance, especially in maximal isometric strength, to date there is still no consensus on the issue. Objectives: The aim of our study was to evaluate differences in isometric handgrip before and after the application of an occlusal splint (OS) in martial arts athletes. Methods: A repeated measures within-subjects design was adopted for the study. Twenty-five young martial arts athletes, specifically of taekwondo (n = 9), ju-jitsu (n = 10) and karate (n = 6), were enrolled in order to study the effects on handgrip peak force while wearing an occlusal splint under two different handgrip test conditions (OS: with occlusal splint vs. NOOS: without occlusal splint), testing both dominant and non-dominant hands. Results: For the dominant hand, comparisons showed a significant increase in handgrip strength under the OS condition (P = 0.01), whereas no significant differences were found for the non-dominant hand for the whole sample. The differences between the OS and NO OS conditions for the dominant hand were present in taekwondo (+8.33%), ju-jitsu (+1.05%) and karate (+2.97%). However, Bonferroni post hoc test showed statistical significance (P = 0.04) only for the taekwondo group. Conclusions: The benefits found with the occlusal splint were statistically significant only during dominant-hand handgrip tasks. Therefore, realignment of the temporomandibular joint (TMJ) via occlusal splints could play a significant role in increasing handgrip peak force only for the dominant hand.
Background:
People clench their teeth to activate facial, neck and abdominal muscles when they need to generate heavy muscle force against large resistance like lifting heavy objects, in order to gain possible ergogenic advantage. These are termed as remote voluntary contractions. Aim of this study was to evaluate the effect of voluntary teeth clenching on maximal voluntary contraction of extensors and flexors of the knee, shoulder and elbow joints of the dominant side during slouch and unsupported upright sitting.
Methods:
One hundred healthy young male adults (mean age 23.3 years) participated in this study. Maximal voluntary contraction was measured using a hand held dynamometer.
Results:
Jaw clenching caused different ergogenic effect during slouch versus unsupported sitting postures. The data revealed that during unsupported upright sitting, the effect of jaw clenching consistently results in larger maximal voluntary contraction of both extensor and flexor muscles of all the three studied joints. However, during slouch sitting, only the maximal voluntary contraction of extensors of elbow and flexors of knee were larger with clenched teeth position.
Conclusions:
Jaw clenching can affect the maximal voluntary contraction of limb muscles which is sitting posture dependent. Jaw clenching can consistently facilitate certain muscles of the upper and lower limbs to generate greater force production during upright sitting.
There appears to be much confusion or misinformation worldwide regarding mouthguards and their use in sports. In an effort to clarify where the international dental community stands on mouthguards and mouthguard research, the workshop looked at some important questions. The goal is to one day formulate consensus statements related to these questions, which will be based on current scientific evidence-based research, to motivate the international community of the importance of dentally fitted laminated mouthguards and the wearing of them by athletes of all sports. There are only five sports in the USA that require the use of mouthguards. If through workshops such as this, the importance of wearing dentally fitted laminated mouthguards can be demonstrated, then more sports may require their athletes to wear them. This article is protected by copyright. All rights reserved.
Background:
Estimation of handgrip strength (HGS) is routinely used by clinicians and epidemiologists for objective assessment of functional status of hand and upper extremity. It is also used as an indirect indicator of overall physical strength and health status in variety of clinical situations and chronic general medical conditions.
Objective:
The present study was conducted to examine the effects of upright and slouch sitting postures and voluntary teeth clenching on hand grip strength in healthy young male subjects.
Methods:
One hundred healthy young males (aged 18-30 years) participated in this study. The HGS was measured using a commercially available dynamometer for the dominant hand. The HGS was measured during four test conditions; (a) slouch sitting without teeth contact, (b) slouch sitting with teeth clenching, (c) upright sitting without teeth contact, and (d) upright sitting with teeth clenching.
Results:
The HGS values were significantly higher during slouch than upright sitting posture, both during similar and opposite teeth related conditions (p< 0.001). Teeth clenching had no effect on the in HGS values during slouch or upright sitting posture (P> 0.05).
Conclusions:
As compared to upright sitting, higher HGS values can be obtained during slouch sitting in young healthy males. Teeth clenching does not affect the HGS values during slouch or upright sitting posture.
This study was performed with the aim of assessing dispositional optimism (DO) in a sample of Parkinson's disease (PD) patients, in order to evaluate its association with clinical outcomes and its impact on rehabilitation. Before entering an outpatient rehabilitation program, 58 participants suffering from idiopathic PD completed the Life Orientation Test-Revised (LOT-R) to evaluate their level of DO, the WHO-5 scale to evaluate their health-related quality of life (HR-QoL), the Hospital Anxiety and De ression Scale (HADS) to identify emotional distress, and the Barthel Index to evaluate their level of disability. All the measures were repeated four months later, at their discharge from the program. Disease stage and severity measures (Unified Parkinson's Disease Rating Scale) were also taken into consideration. Correlations and multivariate regression analyses compared DO with the health-related variables. On admission a high level of DO was found to be associated with less severe disease, a better quality of life (QoL) and lower emotional distress, but not with level of disability (Barthel Index). Consistent results were found at discharge. The level of DO did not change after rehabilitation, while anxiety was significantly reduced, especially in subjects with low LOT-R and high HADS scores. The Barthel Index values significantly improved. At discharge, participants with high DO showed the best improvements in disability and in QoL. Effects of dispositional optimism on quality of life, emotional distress and disability in Parkinson's disease outpatients under rehabilitation In conclusion, a high level of DO was associated with QoL, HADS and UPDRS both on admission and at discharge. The level of DO remained stable after rehabilitation, while disability and anxiety were reduced. Participants with high DO generally had better QoL, and better clinical and psychological performances.
Studies in the literature show that jaw and neck regions are linked anatomically, biomechanically and neurologically. Voluntary clenching has been shown to improve muscle strength and performance of various motor tasks. Information from the neck sensory-motor system is reported to be important for posture. Hence it is reasonable to believe that activation of the jaw sensorymotor system has the potential to modulate posture. In a sample of 116 healthy subjects, we compared center of gravity (COG) velocity during quiet standing on a foam surface during three test positions: i) resting jaw, ii) open jaw, and iii) clenching; these were tested in two conditions: with eyes open and with eyes closed. The COG velocity decreased significantly during clenching in comparison to both open and resting jaw positions (p<0.0001). This suggests that the jaw sensory-motor system can modulate postural mechanisms. We conclude that jaw clenching can enhance postural stability during standing on an unstable surface in both the presence and absence of visual input in healthy adults and suggest that this should be taken into consideration in treatment and rehabilitation planning for patients with postural instability.
The purpose of this study was to assess the effects of concurrent activation potentiation (CAP) on countermovement jump (CMJ) performance. Twenty-four resistance trained males (mean ± SD, age 25 ± 4 years; body mass: 78.7 ± 10.3 kg) performed a CMJ on a force plate under four different conditions: a) a control condition where the CMJ was performed with hands on hips and lips pursed, thus preventing jaw or fist contraction from occurring, b) a jaw condition where the CMJ was performed with maximal contraction of the jaw, c) a fist condition where the CMJ was performed with maximal contraction of the fists, and d) a combined condition where the CMJ was performed with maximal contraction of both jaw and fists. Jump height (JH), peak force (PF), rate of force development (RFD) and time to peak force (TTPF) were calculated from the vertical force trace. There was no significant difference in PF (P = 0.88), TTPF (P = 0.96), JH (P = 0.45), or RFD (P = 0.06) between the four conditions. Effect size (ES) comparisons suggests a potential for the BOTH condition to augment both PF (2.4%; ES: 0.62) and RFD (9.9%; ES: 0.94) over NORM. It is concluded that CAP via singular and combined contractions has no significant impact on CMJ performance, however, substantial inter-individual variation in the response to CAP was observed and such techniques may therefore warrant consideration on an individual basis.This is an open access article distributed under the terms of the Creative Commons Attribution-Noncommercial No Derivatives 3.0 License, which permits downloading and sharing the work provided it is properly cited. The work cannot be changed in any way or used commercially.
Due to the relative newness of such products, there are few investigations into using performance mouthpieces during sport and physical activity to substantiate claims of performance enhancement. The purpose of this study was to investigate the acute effect of a commercially available, non-injury preventive, performance mouthpiece on practical, acute performance measures of power and strength. A within subjects design was used to evaluate twenty one (N=21) recreationally trained, college aged males on the performance of a maximum countermovement vertical jump (CMVJ) from a force platform and one repetition maximum (1RM) bench press exercise for the following conditions: with mouthpiece (MP) and without mouthpiece (noMP). Rate of force development (RFD) and peak vertical force (PF) were derived from force platform data. Statistical analysis revealed no significant differences between conditions for CMVJ height (p=0.13), RFD @ 200ms (p=0.09), PF (p=0.08), and 1RM Bench Press (p=0.45). These data indicate that the use of this particular jaw aligning mouthpiece specifically in an attempt to produce an ergogenic effect on performance is unwarranted.
Although mouth guards were originally designed for injury prevention, even elite athletes are now using performance mouth guards to improve athletic success. Both expensive custom models and over-the-counter models are available, but the efficacy is not well known. Some athletes remain wary of the perceived potential for detriments using a mouth guard to their performance. Thus, the purpose of this study was to examine various physical performance tests when using a mouth guard including a customized over-the-counter mouth guard. Twenty-six trained men (25 ± 4 years; 1.78 ± 0.07 m; 83.3 ± 11.4 kg) and 24 trained women (23 ± 3 years; 1.65 ± 0.08 m; 62.6 ± 7.8 kg) volunteered for the investigation. The subjects completed a familiarization period and then balanced and randomized treatment conditions that included: (a) a customized Power Balance performance mouth guard (PB MG); (b) a regular over the counter boil-and-bite mouth guard (Reg MG); and (c) a no mouth guard (No MG) treatment condition. At each visit, the subjects completed a testing protocol that was sequenced in the following order: sit-and-reach flexibility, medial-lateral balance, visual reaction time, vertical jump, 10-m sprint, bench throw, and plyo press power quotient (3PQ). Heart rate and rating of perceived exertion (RPE) were recorded around the 3PQ. Significance was set at p ≤ 0.05. Expected significant sex differences existed for all power, strength, and speed variables. Bench throw power (watts) and force (newtons) were significantly higher under PB MG than either Reg MG or No MG or in both men and women. The 3PQ power and force production were higher than that for the other 2 treatments for the PB MG for men only. There were no significant differences for treatment conditions in the heart rate or RPE after the 3PQ test. Men were better able to maintain significantly higher 3PQ power production under PB MG treatment condition compared with the other 2 treatment conditions. Rate of power development was significantly higher in men for the vertical jump when using the PB MG compared with that for other treatment conditions in men only. No differences were observed in flexibility, balance, visual reaction time, or sprint time. The PB MG performance mouth guard improves performance of upper-body loaded power exercises in both men and women and lower body power exercise in men without compromising performance on any other performance parameters.
To cite this article: Int J Dent Hygiene9, 2011; 127–131 DOI: 10.1111/j.1601-5037.2010.00458.x Kibayashi M. The relationships among child’s ability of mastication, dietary behaviour and physical fitness.
Abstract: To investigate the relationships between the ability of mastication and physical fitness, and between the ability of mastication and dietary behaviour in children, I examined these parameters using the data of sugar elution rate, physical fitness and athletic ability survey and self-administered questionnaire on dietary behaviour on 171 sixth grade children (88 boys and 83 girls). The sugar elution rate was the index of the ability of mastication and was evaluated by the chewing gum method. The results of self-administered questionnaire on dietary behaviour were used as an index of dietary behaviour. Physical fitness was evaluated by the physical fitness and athletic ability survey of the Ministry of Education, Culture, Sports, Science and Technology, Japan. Regression analysis revealed that the sugar elution rate had significantly positive correlations with the mean grip strength, sit-up, sit-and-reach, repetition side steps and ball throw. The results of self-administered questionnaire on dietary behaviour revealed that the sugar elution rate was significantly higher in children, who had high expectation of food intake and high frequency of vegetable intake, than those with lower parameters. These results suggest that the ability of mastication correlates with physical fitness and dietary behaviour in children.
Concurrent activation potentiation enhances muscular force during open kinetic chain isometric and isokinetic exercises via remote voluntary contractions (RVCs). The purpose of this study was to evaluate the effect of RVCs on the performance of closed kinetic chain ground-based exercises. Subjects included 13 men (21.4+/-1.5 years) who performed the back squat and jump squat in 2 test conditions. The RVC condition included performing the test exercises while clenching the jaw on a mouth guard, forcefully gripping and pulling the barbell down into the trapezius, and performing a Valsalva maneuver. The normal condition (NO-RVC) included performing the test exercises without RVCs. Exercises were assessed with a force platform. Peak ground reaction force (GRF), rate of force development (RFD) during the first 100 milliseconds (RFD-100), RFD to peak GRF (RFD-P), and jump squat height (JH) were calculated from the force-time records. Data were analyzed using an analysis of variance. Results reveal that GRF and RFD-100 were higher in the RVC compared with the NO-RVC condition for both the back squat and jump squat (p<or=0.05). The RFD-P was higher in the RVC compared with NO-RVC condition for the jump squat (p<or=0.05) but not for the back squat (p=0.82). The JH was higher in the RVC compared to the NO-RVC condition for the jump squat (p<or=0.05). This study demonstrates that RVCs enhance the performance of closed kinetic chain exercises for most of the outcome variables assessed, yielding a 2.9-32.3% greater performance. Practitioners should encourage athletes to use RVCs to improve the acute training effect of exercises such as those used in this study.
This study evaluated the effect of remote voluntary contractions(RVC) on concentric isokinetic knee extensor and flexor peak torque, rate of torque development, power, and work, the activation of the affected muscles, and gender differences therein.
Eleven men and 12 women were evaluated with EMG and isokinetic dynamometry during knee extension and flexion tests in RVC and baseline (NO-RVC) test conditions. The RVC condition included jaw clenching, hand gripping, and the Valsalva maneuver. A two-way mixed ANOVA with repeated measures for test condition was used to evaluate the main effects for each isokinetic measure, as well as the EMG of the prime movers, their antagonist,and the muscles involved in the RVC, and the interaction between test condition and gender.
Significant interactions between test condition and gender indicate differences in response to RVC during knee extension tests for power and work (P < or = 0.05) and for knee flexion tests for peak torque and power (P < or = 0.05). All subjects produced higher peak torque and power during knee extension in the RVC condition (P < or = 0.05). Men produced a higher rate of torque development and work during knee extension (P < or = 0.05) and a higher peak torque and power during knee flexion in the RVC condition (P < or = 0.05). Prime mover activation was greater in the RVC condition for most tests (P < or = 0.05). Women demonstrated lower bilateral flexor digitorum superficialis activation than men during all tests in the RVC condition (P < or = 0.05).
RVC increased the performance of several outcome variables assessed, which coincides with the concomitant increase in EMG of the prime movers.
The study assessed the effect of current activation potentiation by evaluating jaw clenching and its effect on the rate of force development (RFD), time to peak force (TTPF), and peak force (PF) during the countermovement jump. Fourteen subjects performed the countermovement jump on a force platform while maximally clenching their jaw on a dental vinyl mouthguard (JAW) as well as without clenching their jaw by jumping with an open mouth (NON-JAW). Results reveal that the RFD was 19.5% greater in the JAW compared with the NON-JAW condition (p < 0.05). The TTPF was 20.15% less in the JAW compared with the NON-JAW condition (p < 0.05). There were no significant differences (p = 0.60) in PF between the JAW and NON-JAW conditions. These findings indicate that concurrent activation potentiation is manifested through jaw clenching during the countermovement jump. As a result, athletes may employ this strategy of maximally clenching their jaws to gain an ergogenic advantage during the countermovement jump.
Concurrent activation potentiation (CAP) is purported to enhance the force capabilities of muscles via the contraction of muscles remote to the prime mover. This phenomenon has been described as remote voluntary contractions (RVC). The objective of this study was to assess a variety of RVC and their effect on isometric knee extensor torque to evaluate the existence of CAP.
Twelve males who regularly participated in lower body resistance training served as subjects. Subjects performed maximum voluntary isometric contractions (MVIC) of the knee extensors without RVC, as well as in a variety of conditions that included RVC, in a randomized order. The RVC conditions included jaw clenching, bilateral gripping, jaw clenching combined with contralateral gripping and the Valsalva maneuver, and the combination of jaw clenching, bilateral gripping, and the Valsalva maneuver.
A repeated-measures ANOVA revealed significant main effects (P = 0.001) for RVC condition. Bonferroni-adjusted post hoc analysis identified several differences in RVC compared with the NO-RVC condition (P < 0.05). The RVC condition including jaw clenching, bilateral gripping, and the Valsalva maneuver resulted in approximately 14.6% and 14.8% greater average and peak torque, respectively, compared with the NO-RVC condition.
These findings indicate that RVC augment torque, which may be useful during the performance of resistance training as well as athletic tasks that require acute maximal strength. These findings support the existence of the CAP phenomenon.
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