EFFECTS OF AN OVER-THE-COUNTER VENTED MOUTHGUARD ON CARDIORESPIRATORY RESPONSES TO EXERCISE AND PHYSICAL AGILITY STEPHEN P. BAILEY,1 THOMAS J. WILLAUER,1 GYTIS BALILIONIS,1 LAURA E. WILSON,1 JOHN T. SALLEY,1 ELIZABETH K. BAILEY,2 AND TONY L. STRICKLAND3 Departments of 1Physical Therapy Education; 2Health and Human Performance, Elon University, Elon, North Carolina; and 3 David Geffen School of Medicine, UCLA, Los Angeles, California ABSTRACT Bailey, SP, Willauer, TJ, Balilionis, G, Wilson, LE, Salley, J, Bailey, EK, and Strickland, TL. Effects of an over-the-counter vented mouthguard on cardiorespiratory responses to exercise and physical agility. J Strength Cond Res 29(3): 678–684, 2015— Many athletes avoid using mouthguards because they believe that they impair their ability to breath and negatively affect performance. Recently, some manufacturers have developed “vented” mouthguards (VentMGs) to address this concern. The purposes of this investigation were to describe the impact of a commercially available “vented” boil-and-bite mouthguard on the physiological responses to graded exercise and to determine whether the use of the same mouthguard influences performance during traditional physical agility tests. Recreationally trained males (n = 15) (age = 24 6 1 year; V_ O2max = 43.5 6 1.9 ml$kg21$min21; body mass index = 25.2 6 0.9) completed 3 randomly assigned trials where they wore no mouthguard (control), a traditional mouthguard (TradMG), or a VentMG. During each trial, subjects completed a modified maximal exercise test on a cycle ergometer and a series of physical agility tests (40-m dash, vertical leap, broad jump, 3-cone drill, and shuttle run). No differences were seen between control and the TradMG in any cardiorespiratory measures at any time during the maximal exercise test. Ventilation and blood lactate were lower (p # 0.05) during VentMG at 200 W and at MAX; however, no differences in V_ O2max were observed. Although TradMG had no impact on physical agility, VentMG produced a higher (1.9 cm; p = 0.03) vertical leap than control. Both mouthguard conditions negatively affected perceptions of breathability, comfort, and ability to communicate, but no differences existed between the 2 conditions. These findings confirm that TradMG has no negative impact on physiological function

Address correspondence to Stephen P. Bailey, [email protected]. 29(3)/678–684 Journal of Strength and Conditioning Research Ó 2015 National Strength and Conditioning Association

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during exercise and physical agility; however, VentMG may have a positive impact at higher workload and on vertical leap.

KEY WORDS ventilation, mouthpiece, performance INTRODUCTION

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outhguards have been effectively used for decades to minimize myofacial injury during various sports (1,17,19). Mouthguards have also been proposed to reduce the risk of concussions during sport-related activity; however, the data supporting this claim are not consistent. The National Collegiate Athletic Association requires the use of mouthguards in 4 sports (football, ice hockey, field hockey, and lacrosse), and the American Dental Association recommends the use of mouthguards in 29 sports/activities. Despite the clear potential of mouthguards to reduce the risk of injury, many athletes avoid the use of mouthguards because they believe mouthguards inhibit breathing, gas exchange, and communication. There are several different types of mouthguards available for use including stock mouthguards, boil-and-bite mouthguards, and professionally custom–fitted mouthguards. The type of mouthguard used may impact the athlete’s ability to breath during activity. For example, Garner et al. (13) suggest that a custom-fitted mouthguard can actually improve ventilation and gas exchange, whereas work by Delaney and Montgomery (9) indicates that the use of a boil-and-bite mouthguard may have a negative impact on maximal ventilation and oxygen consumption. Recently, some manufacturers have provided a “vented” version of the boil-and-bite mouthguard in an effort to improve ventilation and gas exchange during sports performance. The impact of this type of mouthguard on physiology during aerobic activity is unclear. The impact of mouthguards on performance of power activities is also frequently discussed. There are several studies that describe improvements in power performance activities when using a mouthguard such as the countermovement vertical jump (4,10). In contrast, there are several

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other studies that do not show improvements in power activities when using a mouthguard (8). It does seem that positive improvements in power activities tended to occur when a custom-fitted mouthguard was used in competitive athletes. As a consequence, the impact of a “vented” mouthguard (VentMG) on power activities has yet to be described. The “vented” boil-and-bite mouthguard may be used more frequently than a custom-fitted mouthguard because of dramatic differences in cost and accessibility. The purposes of this investigation were (a) to describe the impact of a commercially available “vented” boil-andbite mouthguard on the physiological responses to graded exercise and (b) to determine whether the use of the same mouthguard influences performance during traditional power performance activities. It is hypothesized that the use of a “vented” boil-and-bite mouthguard will improve ventilation and gas exchange as compared with a traditional mouthguard (TradMG) during graded exercise. It is also hypothesized that the use of a “vented” boil-and-bite mouthguard will have no different impact than a TradMG on performance of power activities.

METHODS

Figure 1. Traditional and vented boil-and-bite mouthguards.

Experimental Approach to the Problem

This investigation used a within-subject repeated-measures design that required subjects to report to the laboratory on 4 occasions. On the first occasion, subjects were oriented to all of the experimental procedures and fitted with both mouthguards used in the investigation. The subsequent 3 sessions were completed under 3 different experimental conditions: No mouthguard (control), TradMG, or VentMG (Figure 1). These experimental sessions occurred at least 1 week apart and were applied in a randomized counterbalanced fashion. Subjects completed all experimental sessions at the same time of the day and were instructed to maintain the same dietary habits but were to abstain from consumption of anything other than water for the 2 hours before testing. Subjects also abstained from participating in any other physical activity for 24 hours before each experimental session. During each experimental session, subjects completed a series of physical agility tests and a modified maximal exercise test. After completion of the physical agility tests, subjects rested for 30 minutes before completing the modified maximal exercise test. During all activities, subjects wore the predetermined mouthguard assigned to that experimental session. Subjects

Fifteen males (age = 24 6 1 year; V_ O2max = 43.5 6 1.9 ml$kg21$min21; body mass index = 25.2 6 0.9) served as subjects in this investigation. All subjects exercised on a regular basis (.5 times a week for at least 30 minutes per session) and had experience wearing a traditional boil-andbite mouthguard during at least 3 athletic seasons. None of the subjects had used a mouthguard during the previous

year. According to ACSM’s Guidelines for Exercise Testing and Prescription, the aerobic fitness of subjects ranged from poor to excellent (poor = 4, fair = 4, good = 3, excellent = 4) (3). Subjects were excluded from the investigation if they had any orthopedic, metabolic, or cardiorespiratory issues that prevented them from safely completing the experimental procedures. Before participation, subjects had the experimental risks and benefits explained to them and then read and signed an informed consent form. This investigation was approved by the University’s Institutional Review Board for Protection of Human Subjects in Research. Procedures

Physical Agility Tests. The physical agility tests included 5 tests often used to assess physical performance abilities in athletes: 40-m dash, vertical jump, broad jump, 3-cone drill, and shuttle run. Before these tests, the subjects warmed up by running approximately 800 m at a self-selected pace. Blood lactate was measured immediately before the warmup and after completion of all the tests. Subjects were given 1-minute rest between each test, and the tests were applied in the order described below. After completion of the tests, subjects completed a Mouth Guard Satisfaction Questionnaire (MGS-Q).

Forty-Meter Dash. Time to run 40 m was evaluated with a traditional stopwatch. Subjects started in the same position each time and sprinted the predetermined distance (22). The evaluator positioned the subject at the start line and then moved to the finish line. The investigator started the test by saying “Ready?.Go!” with a consistent VOLUME 29 | NUMBER 3 | MARCH 2015 |

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Effects of Vented Mouthguard on Physiology and Performance cadence between the 2 instructions. Subjects completed 3 trials and rested 30 seconds between each 40-m dash.

Vertical Jump Test. Vertical leap height was measured using the Vertec jump training system (18). Participants completed 3 jumps separated by 30 seconds. Standing next to Vertec system, subjects were asked to raise their dominant arm above their head as high as possible. Participants were then instructed to assume a squat position with arms by their hips before jumping. Participants then jumped as high as they could and tapped the highest vane on the Vertec system. Vertical leap was measured to the nearest centimeter. Broad Jump Test. Participants stood on a tiled floor with legs shoulder width apart. The participant was then instructed to jump forward as far as possible so that they could land without moving. Participants completed 3 jumps separated by 30 seconds. Distance jumped was measured to the nearest 1 cm (20). Three-Cone Drill. For this test, 3 cones were placed in an L-shape, each 5 m apart (22). The participant completed 3 trials separated by 30 seconds. During each trial, subjects ran from the first cone, circled the second cone, ran around the third cone, and then returned to the first cone using the same pattern. For this test, subjects initiated the start on their own and the investigator started timing with the initiation of movement. Shuttle Run. For this test, the participant started in a 3-point stance (1 hand on the ground). Upon a whistle blown by the investigator, the participant moved as fast as possible 5 m to his right, returned 10 m to the left, pivoted, and then ran forward for 5 m. The participant completed 3 trials separated by 30 seconds (20). Modified Maximal Exercise Test. After a 30-minute rest, subjects completed a modified maximal exercise test on a Lode Corival electronically braked cycle ergometer (Groningen, the Netherlands). After a 1-minute warm-up at 25 W, participants began exercising at 50 W, and the workload was increased 50 W every 5 minutes for the first 4 stages. After these initial 4 stages, the workload was increased 25 W per minute until the subject was unable to maintain a workload within 10% of desired for 30 seconds. During the maximal exercise test, respiratory gas analysis was performed using a Parvo Medics True One 2400 Metabolic Cart (Sandy, UT, USA). To complete these measurements, subjects wore a Hans Rudolph 7450 V2 mask, which was fitted to their face size (Hans Rudolph, Shawnee, KS, USA). The accuracy and reliability of the Parvo Medics Metabolic Cart has been established by Bassett et al. (5). Heart rate and the amount of oxygen in the blood (pulse oximetry, O2sat) were recorded every minute during the test, and ratings of perceived exertion (RPE) were collected at the middle of each exercise stage. Blood lactate concentrations were recorded during the last minute of the 4 initial exercise stages and when subjects achieved their maximal workload.

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All testing was completed in a normal environment (228 C and 50% humidity). After dismounting the cycle ergometer, subjects again completed a MGS-Q. Mouthguard Conditions. As described previously, subjects completed the experimental sessions under 3 different experimental conditions: control, TradMG, or VentMG. During the VentMG condition, subjects wore a Nike adult intake convertible mouthguard (Nike, Beaverton, OR, USA). This mouthguard has breathing channels designed to facilitate gas exchange. During the TradMG condition, subjects wore a Nike Mouthguard identical to the VentMG except it does not have the breathing channels. All mouthguards were fitted to the participant using the instructions provided on the packaging. Specifically, the mouthguard was placed in boiling water for 30 seconds. It was then removed and the water gently shaken off. The mouthguard was then carefully placed in the mouth so it covered the upper teeth and then the subject was instructed to firmly bite down. Moderate pressure was then placed on the lips and cheeks for 30 seconds. The subject then opened and closed their mouth several times, and a proper fit was ensured if the mouthguard stayed in place and was not easily dislodged by normal mouth movement. Mouthguards were applied in a blinded fashion so the participant was not aware which mouthguard he was wearing. To do so, the mouthguard was placed into the subject’s mouth by an investigator wearing protective gloves while the subject’s eyes were covered with a blindfold. Analytical Procedures

Heart Rate and Pulse Oximetry. Heart rate and the amount of oxygen in the blood (pulse oximetry) were monitored during all testing using a Nonin Model 3150 wrist-worn pulse oximeter (measurement error below 0.3%) (Nonin, Plymouth, MN, USA). Blood Lactate. Blood lactate was measured using a Nova Biomedical Lactate Plus Blood Lactate Measuring Meter (Waltham, MA, USA) (23). Blood was collected by fingertip lancing using a single-use sterile 28-G lancet to collect 0.7 ml of blood for each measurement. Hart et al. (16) have reported the reliability of the Lactate Plus to be very strong (r = 0.99). Mouth Guard Satisfaction Questionnaire. Subjects completed a MGS-Q 2 times during each experimental session, after completion of the physical agility tests and after completion of the modified maximal exercise test. The MGS-Q asked subjects to rate the mouthguard on a scale from 0 (poor) to 10 (excellent) for comfort, breathability, and ability to communicate. These procedures are similar to those used by Delaney and Montgomery (9). Statistical Analyses

All data are presented as mean 6 SE. Test-retest reliability of the physical agility tests demonstrated excellent intraclass

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TABLE 1. Cardiorespiratory responses to graded exercise under the 3 mouthguard conditions.*

Workload Rest 50 W 100 W 150 W 200 W Max

Cond Control TradMG VentMG Con TradMG VentMG Control TradMG VentMG Control TradMG VentMG Control TradMG VentMG Control TradMG VentMG

V_ O2 (L$min21) 0.45 0.48 0.50 1.09 1.07 1.06 1.61 1.67 1.63 2.33 2.31 2.33 3.16 3.16 3.11 3.49 3.48 3.48

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

0.02 0.04 0.04 0.02 0.02 0.02 0.03 0.02 0.04 0.05 0.03 0.04 0.07 0.06 0.06 0.13 0.13 0.17

V_ CO2 (L$min21) 0.32 0.34 0.34 0.85 0.82 0.82 1.38 1.44 1.40 2.17 2.16 2.16 3.09 3.13 3.03 3.63 3.62 3.62

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

Ve (L$min21)

0.02 12.22 6 0.66 0.02 12.73 6 0.87 0.02 12.69 6 0.52 0.03 26.33 6 0.67 0.02 25.21 6 0.76 0.01 24.81 6 0.43 0.03 38.92 6 1.12 0.03 39.88 6 1.30 0.03 38.70 6 0.84 0.04 60.22 6 2.26 0.03 60.48 6 1.87 0.04 58.46 6 1.83 0.07 91.92 6 4.82 0.07 94.28 6 3.23 0.05 86.91 6 2.85† 0.15 123.29 6 6.21 0.15 121.94 6 6.45 0.20 113.16 6 7.66†

RER 0.72 0.69 0.70 0.77 0.77 0.78 0.86 0.87 0.87 0.93 0.94 0.92 0.98 0.99 0.97 1.04 1.04 1.03

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

0.02 0.02 0.01 0.02 0.01 0.02 0.02 0.02 0.03 0.02 0.02 0.02 0.01 0.03 0.02 0.02 0.01 0.02

Heart rate (b$min21) 98 101 95 110 111 110 129 128 126 153 153 150 174 173 170 180 181 178

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

2 2 3 2 2 3 3 3 3 3 4 4 3 4 3 4 3 4

RPE NA NA NA 1.6 6 0.2 1.6 6 0.2 1.6 6 0.3 2.9 6 0.2 3.0 6 0.3 2.8 6 0.3 4.2 6 0.3 4.8 6 0.4 4.3 6 0.3 6.5 6 0.4 6.9 6 0.4 6.5 6 0.4 9.8 6 0.1 9.9 6 0.1 9.9 6 0.2

O2Sat (%) 95.4 94.3 94.6 94.9 94.3 95.0 95.1 94.6 95.2 95.0 94.6 95.4 94.6 94.6 95.3 94.6 94.2 93.4

6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6

0.6 0.5 0.3 0.5 0.4 0.4 0.4 0.4 0.4 0.5 0.4 0.4 0.5 0.5 0.3 0.4 0.6 0.4

*Control = no mouthguard; TradMG = traditional mouthguard; VentMG = vented mouthguard; RER = respiratory exchange rate; RPE = rating of perceived exertion. †Indicates significant differences between VentMG and other mouthguard conditions at specific workload.

correlation coefficients of R $ 0.95 (21). Differences between mouthguard conditions in performance of the physical agility tests and questionnaire responses were analyzed using a multiple analysis of variance (MANOVA). Differences between mouthguard conditions in measurements taken during the modified maximal exercise test were analyzed using a 2-way MANOVA with repeated

measures (mouthguard condition 3 time). When differences between conditions or across time were observed, specific differences between conditions were evaluated using the Tukey post hoc test. Data were analyzed using the IBM Statistics package software version 21.0 (IBM Statistics, Armonk, NY, USA). Significance in this study was set a priori at p # 0.05.

RESULTS

Figure 2. Impact of mouthguard condition on blood lactate during graded exercise. *Indicates significant differences between VentMG and other mouthguard conditions at specific workload.

cardiorespiratory responses to graded exercise are presented in Table 1. No differences between the 3 conditions were observed for V_ O2, V_ CO2, RER, O2sat, and heart rate at any workload. Ve was observed to be lower during VentMG as compared with control and TradMG at 200 W and at Max (p # 0.05) (Table 1). Similarly, blood lactate was observed to be lower during VentMG as compared with control and TradMG at 200 W and at Max (p # 0.05) (Figure 2). The effect of the mouthguard treatment on RPE VOLUME 29 | NUMBER 3 | MARCH 2015 |

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Effects of Vented Mouthguard on Physiology and Performance 0.7; VentMG = 4.5 6 0.5), and ability to communicate (TradMG = 3.2 6 0.8; VentMG = 3.1 6 0.6).

TABLE 2. Performance during physical agility tests under the 3 mouthguard conditions.* 40-m sprint (s) Control TradMG VentMG Vertical leap (cm) Control TradMG VentMG Broad jump (cm) Control TradMG VentMG Three-cone drill (s) Control TradMG VentMG Shuttle run (s) Control TradMG VentMG

DISCUSSION

5.78 6 0.13 5.81 6 0.12 5.82 6 0.12 56.9 6 2.1 56.6 6 2.3 58.8 6 2.0† 220.3 6 5.8 219.7 6 6.1 221.9 6 5.7 9.65 6 0.11 9.64 6 0.13 9.71 6 0.13 5.05 6 0.10 5.10 6 0.08 5.05 6 0.06

*Control = no mouthguard; TradMG = traditional mouthguard; VentMG = vented mouthguard. †Indicates difference between VentMg and other mouthguard conditions.

during exercise approached significance (p = 0.08). Although not statistically significant, these potential differences can be seen while subjects were exercising at 150 and 200 W, where the TradMG tended to result in higher RPE than the control and VentMG conditions (Table 1). Performance during the physical agility tests is presented in Table 2. No differences between the 3 conditions were observed in the 40-m dash, broad jump, 3-cone drill, and shuttle run. Performance during the vertical jump test was observed to be greater during VentMG compared with control and TradMG (p # 0.05) (Table 2). In comparison, blood lactate was not different between the conditions after completion of the physical agility tests (control = 9.3 6 0.7 mmol, TradMG = 8.6 6 0.5 mmol, VentMG = 9.1 6 0.8 mmol). Perceptions of comfort, breathability, and ability to communicate were consistently negatively affected by wearing a mouthguard during the physical agility tests and graded exercise (p # 0.05). No differences were observed after completion of the physical agility tests between the 2 mouthguard conditions in comfort (TradMG = 4.7 6 0.8; VentMG = 4.9 6 0.6), breathability (TradMG = 5.4 6 0.7; VentMG = 5.1 6 0.5), and ability to communicate (TradMG = 3.8 6 0.7; VentMG = 3.4 6 0.6). Similarly, no differences were observed after completion of the graded exercise test between the 2 mouthguard conditions in comfort (TradMG = 5.8 6 0.8; VentMG = 4.9 6 0.6), breathability (TradMG = 4.8 6

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This investigation sought to examine the impact of 2 different boil-and-bite mouthguards on physical agility and cardiorespiratory responses to graded exercise. This investigation is unique for several reasons. Many previous experiments compare the effects of a TradMG to a control condition (no mouthguard) or a comparatively expensive custom-designed mouthguard. This is the first investigation to examine the effect of a relatively inexpensive (;US$ 15) and accessible mouthguard that is specifically designed to facilitate airflow. This investigation is also unique in that it examined the impact of the mouthguards on both cardiorespiratory responses to exercise and the ability to perform common physical agility tests. This investigation also made a special effort to blind subjects from the treatment condition. Similar to the results from previous investigations, our data also suggest that the use of a regular boil-and-bite mouthguard has no negative effects on cardiorespiratory function during graded exercise (6,15). Similar findings were observed for the VentMG except in ventilation and blood lactate. Ventilation and blood lactate were both lower in the VentMG condition at the 2 highest workloads (200 W and max) compared with the control and TradMG conditions. Because V_ O2, V_ O2max, and all other measures were unchanged as a result of the mouthguard condition, these findings could suggest that at the higher workloads subjects were better able to maintain aerobic energy production in the VentMG condition. Although the result was not significant, RPE also tended to be lower at the higher workloads in the VentMG. Together these findings imply that a VentMG may be advantageous at higher workloads compared with a TradMG. The impact of these differences on aerobic performance remains unclear. The only measure of aerobic performance in this investigation is V_ O2max, and no differences _ O2max between the treatment conditions. As were observed in V a result, we cannot conclude that the differences seen here in ventilation and blood lactate would have an impact on aerobic performance. Garner et al. (13) completed an investigation examining the effects of a custom-fitted mandibular mouthguard (designed to create an opening between the maxillary and mandibular teeth) on gas exchange parameters while running at 6.5 mph and 0% grade. These authors found that the use of this mouthguard increased V_ O2 and V_ CO2 during running and hypothesized that the use of this mouthguard improved airway dynamics during exercise (13). This conclusion does seem plausible because these authors previously demonstrated that the use of this specific mouthguard increased airway diameter by 9% (14). An alternative conclusion from these data may be that application of this specific mouthguard increased the work of breathing demanding greater

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Journal of Strength and Conditioning Research metabolic activity. We have no information regarding the impact of the VentMG on airway diameter, and it is certainly possible that the differences seen in gas exchange could be due to specific mouthguard construction. It is also possible that the different modes of exercise (running vs. cycling) used in these investigations facilitated slightly different responses. The mechanisms underlying the reduction in ventilation at the higher workloads seen here remain unclear. Francis and Brasher (12) also observed decreases in ventilation during cycle ergometry while wearing a mouthguard and hypothesized that the mouthguard prompted subjects to “pursed lip breath,” which has been shown to improve respiratory efficiency during exercise in people with lung disease (7). Pursed lip breathing prevents airways from closing too early and trapping “stale” air by creating back pressure inside the airways. Although it is unclear if pursed lip breathing has similar effects in people with normal lung function, the design of the VentMG seems to be ideally suited to facilitate this behavior during exercise. Of particular interest in this investigation was the impact of VentMG on blood lactate levels. Our results are similar to Garner and McDivitt (14) who found blood lactate to be lower after a 30-minute run when subjects wore a mandibular mouthguard. During this investigation, these authors also found airway diameter to be increased (14). As a result, they hypothesized that lactate was reduced because subjects had increased ventilation and thus were better able to eliminate CO2. However, Garner and McDivitt were not able to measure gas exchange parameters during the run, so it is unclear whether ventilation was increased or decreased during their investigation. Use of the 2 different mouthguards had no impact on performance of various physical agility tests that are often used to assess physical performance. The only exception was that vertical leap height was found to be greater in the VentMG group than in the control and TradMG groups. Previous investigations examining the impact of mouthguards on activities relying on muscular power have produced mixed results. Most recently, an investigation by Allen et al. (2) found that the use of a mouthguard had no impact on power-related performance. These results are of particular interest to this investigation because the types of subjects used in that investigation (recreational athletes) were similar to those used in our investigation. In contrast, Dunn-Lewis et al. found an improvement in vertical leap height and other power measures when using an over-the-counter mouthguard (10). Jaw clenching alone has been found to improve performance of power activities (11), and it is possible that application of a mouthguard could influence position of the jaw and facilitate effective jaw clenching. We provided no instructions to our subjects regarding jaw clenching in this investigation; however, it does seem that natural jaw clenching may have most likely occurred during the vertical leap test. As a consequence, it may be possible that the VentMG influenced this phenomenon. This possibility will need to be examined in future investigations.

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Subjects using mouthguards consistently indicate that they feel that their breathing is impaired and they are uncomfortable (9). Findings from this investigation support this conclusion, and no perceptual differences were reported between the 2 mouthguard conditions. All of our subjects had previous experience wearing a mouthguard during sport activity; however, it is possible that regular or everyday use of a mouthguard could influence these perceptions. The findings of this investigation are limited in several ways. Inclusion of a more applicable aerobic performance measure (e.g., 1-mile run time) would have been valuable to determine if the physiological differences observed during graded exercise had any practical significance. Furthermore, the methods used to evaluate physical agility were similar to those used in the field, and it is possible that more precise measurement of performance may have yielded different results. Imaging of the upper airways while wearing the 2 different mouthguards may have also been valuable in the interpretation of the results seen here.

PRACTICAL APPLICATIONS The results of this investigation confirm that the use of a TradMG does not have deleterious effects on gas exchange during exercise or performance of various physical agility tests. Use of an over-the-counter VentMG may positively influence ventilation and lactate production at higher workloads; however, no impact on aerobic performance was observed in this investigation. Use of a VentMG also improved vertical leap height but had no other impact on performance of various physical agility tests. The potential impact of a VentMG on physical performance should be further examined. Thus, the use of an over-the-counter VentMG does not seem to provide any extraordinary benefit to the athlete as compared with a TradMG.

ACKNOWLEDGMENTS The funding for this project was provided by the Sports Concussion Institute Global Inc, Los Angeles, CA. The authors also wish to thank their subjects for their consistent participation. This was an independent investigation and the results of this study do not constitute endorsement of the product by the National Strength and Conditioning Association.

REFERENCES 1. ADA Council on Access, Prevention and Interprofessional Relations, and ADA Council on Scientific Affairs. Using mouthguards to reduce the incidence and severity of sports-related oral injuries. J Am Dent Assoc 137: 1712–1720, 2006. quiz 1731. 2. Allen, CR, Dabbs, NC, Zachary, CS, and Garner, JC. The acute effect of a commercial bite-aligning mouthpiece on strength and power in recreationally trained men. J Strength Cond Res 28: 499– 503, 2014. 3. American Collge of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription. Baltimore, MD: Lippincott, Williams, & Wilkins, 2013. VOLUME 29 | NUMBER 3 | MARCH 2015 |

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Effects of Vented Mouthguard on Physiology and Performance 4. Arent, SM, McKenna, J, and Golem, DL. Effects of a neuromuscular dentistry-designed mouthguard on muscular endurance and anaerobic power. Comperative Exerc Physiol 7: 73–79, 2010.

14. Garner, DP and McDivitt, E. Effects of mouthpiece use on airway openings and lactate levels in healthy college males. Compend Contin Educ Dent 30 Spec No 2: 9–13, 2009.

5. Bassett, DR Jr, Howley, ET, Thompson, DL, King, GA, Strath, SJ, McLaughlin, JE, and Parr, BB. Validity of inspiratory and expiratory methods of measuring gas exchange with a computerized system. J Appl Physiol (1985) 91: 218–224, 2001.

15. Gebauer, DP, Williamson, RA, Wallman, KE, and Dawson, BT. The effect of mouthguard design on respiratory function in athletes. Clin J Sport Med 21: 95–100, 2011.

6. Bourdin, M, Brunet-Patru, I, Hager, PE, Allard, Y, Hager, JP, Lacour, JR, and Moyen, B. Influence of maxillary mouthguards on physiological parameters. Med Sci Sports Exerc 38: 1500–1504, 2006. 7. Cabral, LF, D’Elia, TC, Marins, DS, Zin, WA, and Guimaraes, FS. Pursed lip breathing improves exercise tolerance in copd: A randomized crossover study. Eur J Phys Rehabil Med 2014. Epub ahead of print. 8. Cetin, C, Kececi, AD, Erdogan, A, and Baydar, ML. Influence of custom-made mouth guards on strength, speed and anaerobic performance of taekwondo athletes. Dent Traumatol 25: 272–276, 2009. 9. Delaney, JS and Montgomery, DL. Effect of noncustom bimolar mouthguards on peak ventilation in ice hockey players. Clin J Sport Med 15: 154–157, 2005. 10. Dunn-Lewis, C, Luk, HY, Comstock, BA, Szivak, TK, Hooper, DR, Kupchak, BR, Watts, AM, Putney, BJ, Hydren, JR, Volek, JS, Denegar, CR, and Kraemer, WJ. The effects of a customized overthe-counter mouth guard on neuromuscular force and power production in trained men and women. J Strength Cond Res 26: 1085–1093, 2012.

16. Hart, S, Drevets, K, Alford, M, Salacinski, A, and Hunt, BE. A method-comparison study regarding the validity and reliability of the Lactate Plus analyzer. BMJ Open 3: e001899, 2013. 17. Knapik, JJ, Marshall, SW, Lee, RB, Darakjy, SS, Jones, SB, Mitchener, TA, delaCruz, GG, and Jones, BH. Mouthguards in sport activities: History, physical properties and injury prevention effectiveness. Sports Med 37: 117–144, 2007. 18. Leard, JS, Cirillo, MA, Katsnelson, E, Kimiatek, DA, Miller, TW, Trebincevic, K, and Garbalosa, JC. Validity of two alternative systems for measuring vertical jump height. J Strength Cond Res 21: 1296–1299, 2007. 19. Mihalik, JP, McCaffrey, MA, Rivera, EM, Pardini, JE, Guskiewicz, KM, Collins, MW, and Lovell, MR. Effectiveness of mouthguards in reducing neurocognitive deficits following sportsrelated cerebral concussion. Dent Traumatol 23: 14–20, 2007. 20. Myer, GD, Schmitt, LC, Brent, JL, Ford, KR, Barber Foss, KD, Scherer, BJ, Heidt, RS Jr, Divine, JG, and Hewett, TE. Utilization of modified NFL combine testing to identify functional deficits in athletes following ACL reconstruction. J Orthop Sports Phys Ther 41: 377–387, 2011.

11. Ebben, WP, Flanagan, EP, and Jensen, RL. Jaw clenching results in concurrent activation potentiation during the countermovement jump. J Strength Cond Res 22: 1850–1854, 2008.

21. Portney, LG and Watkins, MP. Foundations of Clinical Research: Applications to Practice. Upper Saddle River, NJ: Pearson Prentice Hall, 2009.

12. Francis, KT and Brasher, J. Physiological effects of wearing mouthguards. Br J Sports Med 25: 227–231, 1991.

22. Robbins, DW, Goodale, TL, Kuzmits, FE, and Adams, AJ. Changes in the athletic profile of elite college American football players. J Strength Cond Res 27: 861–874, 2013.

13. Garner, DP, Dudgeon, WD, Scheett, TP, and McDivitt, EJ. 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, 2011.

684

the

23. Tanner, RK, Fuller, KL, and Ross, ML. Evaluation of three portable blood lactate analysers: Lactate Pro, Lactate Scout and Lactate Plus. Eur J Appl Physiol 109: 551–559, 2010.

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Effects of an over-the-counter vented mouthguard on cardiorespiratory responses to exercise and physical agility.

Many athletes avoid using mouthguards because they believe that they impair their ability to breath and negatively affect performance. Recently, some ...
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