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The trigeminal blink response is an easily evoked brainstem reflex. Despite extensive investigation, there has been limited study of how parametric manipulation of the intensity of stimulation modulates the evoked response. The goal of this study was to measure the psychometric trigeminal reflex sensitivity function, test the resulting model parameters for differences between contralateral and ipsilateral reflex responses, and test for individual differences in sensitivity. We measured blink responses in 17 healthy, adult participants using airpuffs delivered to the cornea at five different, log-spaced intensities (3.5 - 60 PSI). Lid position over time was decomposed into amplitude, velocity, and shape components. We found that variation in blink amplitude was well fit with a two-parameter Weibull cumulative density function of log stimulus intensity. There was a reliable decrease in threshold sensitivity of the contralateral as compared to ipsilateral blink response. This decrease was consistent across participants despite substantial individual differences in the threshold and slope of the overall sensitivity function, suggesting that the laterality effect arises in the neural circuit subsequent to individual differences in sensitivity. We conclude that a parametric measure of trigeminal reflex sensitivity is a promising tool for examining neural mechanisms that modulate this response.

Objective Sleep apnea research cites that an oral appliance, which places the mandible in a more forward position and the genioglossus (tongue muscle) on the floor of the mouth, improves aspects of the pharyngeal opening. Exercise science research has cited improvements in airway dynamics and physiological variables with oral appliance use during exercise. Thus, the purpose of this study was to design an oral appliance that would act on the genioglossus and determine if there were effects on respiratory parameters while exercising. Materials and methods Seventeen healthy subjects ages 18–43 participated in this study. Prior to the exercise protocol, the order of the oral applicance (OA) or no oral appliance (no OA) condition was randomly assigned to subjects, with subjects completing both conditions. Respiratory parameters (respiratory rate, ventilation, oxygen, and carbon dioxide) were measured between conditions while subjects ran for 10 min at steady state. Results The results demonstrated that both respiratory rate (25.97 BPM, OA and 28.35 BPM, no OA) and ventilation (47.66 l/min, OA and 50.34 l/min, No OA) were significantly lowered (p < .01) in the OA condition. There were no differences in carbon dioxide (1.89 l/min, no OA and 1.88 l/min, OA) or oxygen outcomes (2.17 l/min, no OA and 2.17 l/min OA). Discussion The outcomes from this study suggest that the design of the oral appliance elicits an effect on the genioglossus, thereby resulting in lowered respiratory rate and ventilation with no negative effects on oxygen uptake during exercise.

Spinal cord injury (SCI) is associated with devastating neurological deficits affecting more than 11,000 Americans each year. Although several therapeutic agents have been proposed and tested, no FDA-approved pharmacotherapy is available for SCI treatment. We have recently demonstrated that estrogen (E2) acts as an antioxidant and anti-inflammatory agent, attenuating gliosis in SCI. We have also demonstrated that nanoparticle-mediated focal delivery of E2 to the injured spinal cord decreases lesion size, reactive gliosis, and glial scar formation. The current study tested in vitro effects of E2 on reactive oxygen species (ROS) and calpain activity in microglia, astroglia, macrophages, and fibroblasts, which are believed to participate in the inflammatory events and glial scar formation after SCI. E2 treatment decreased ROS production and calpain activity in these glial cells, macrophages, and fibroblast cells in vitro. This study also tested the efficacy of fast- and slow-release nanoparticle-E2 constructs in a rat model of SCI. Focal delivery of E2 via nanoparticles increased tissue distribution of E2 over time, attenuated cell death, and improved myelin preservation in injured spinal cord. Specifically, the fast-release nanoparticle-E2 construct reduced the Bax/Bcl-2 ratio in injured spinal cord tissues, and the slow-release nanoparticle-E2 construct prevented gliosis and penumbral demyelination distal to the lesion site. These data suggest this novel E2 delivery strategy to the lesion site may decrease inflammation and improve functional outcomes following SCI.

A spinal cord injury (SCI) may lead to loss of strength, sensation, locomotion and other body functions distal to the lesion site. Individuals with SCI also develop secondary conditions due to the lack of skeletal muscle activity. As SCI case numbers increase, recent studies have attempted to determine the best options to salvage affected musculature before it is lost. These approaches include pharmacotherapeutic options, immunosuppressants, physical activity or a combination thereof. Associated biomarkers are increasingly used to determine if these treatments aid in the protection and reconstruction of affected musculature.

Qualitative assessments of the blink reflex are used clinically to assess neurological status in critical care, operating room, and rehabilitative settings. Despite decades of literature supporting the use of quantitative measurements of the blink reflex in the evaluation of multiple neurological disorders, clinical adoption has failed. Thus, there remains an unmet clinical need for an objective, portable, non-invasive metric of neurological health that can be used in a variety of settings. We have developed a high-speed videography-based device to trigger, record, and analyze a blink reflex. A pilot study was performed to compare the device’s measurements to the published literature of electromyographic measurements, currently the gold standard. The study results indicate that the device is a viable tool to obtain fast, objective, and quantitative metrics of a blink reflex, and has promise as a non-invasive diagnostic assessment of neurological health., The positions of the right (red) and left (blue) eyelids during a stimulated blink are tracked over time using image processing. The technique produces rapid, non-invasive, and objective measurements of blink parameters, making it a useful tool for assessing neurological function.

Studies have demonstrated positive results for people who practice traditional yoga, specifically in body mass index, depression, cancer, sleeping patterns, and diabetes. Most forms of traditional yoga are held in a temperate climate between 293 Kelvin (K) to 295 K; a temperature that is calming and places little stress on the body. Bikram yoga, however, is a more intense form of yoga performed in a hotter climate, typically at 314 K with 40% humidity. The purpose of this study was to determine how Bikram yoga affected blood pressure, body composition, and sleep patterns in beginner and intermediate/experienced practitioners. Participants (N=16) completed 8 weeks of sessions, ranging between 2 to 7 classes per week in a local Bikram yoga program conducted by certified instructors. All participants were assessed prior to the study and again at the end of the eight weeks. A BOD POD (an air displacement plethysmography) was used for body composition assessments, while a digital blood pressure cuff was used to assess blood pressure. In addition, participants were also surveyed on sleep parameters pre and post yoga participation. In combining all subjects, results showed there was a significant improvement (p=0.054) in faster time to fall asleep (27.66 min pre and 23.967 min post), and a trend (p=0.057) towards improved mean arterial pressure (92.20 mmHg pre and 88.33 mm Hg post). There were no differences in weight loss or percent body fat in subjects. This study indicates that there is a trend towards improved blood pressure and significant improvement in sleep parameters after 8 weeks of Bikram yoga for both intermediate/experienced and beginners, but no differences in body composition.

The Centers for Disease Control and Prevention estimates 1.6–3.8 million concussions occur each year. Research cites that 21% of traumatic brain injury in children/youth results from participation in sports and recreational activities. However, current methods to assess concussion, which includes balance, neurocognitive, and self-report assessments, provide conflicting validity and reliability. Thus, many sports medicine professionals seek more objective measures to assess the severity and outcomes of a concussive event. The purpose of this study was to utilize a novel technology to determine if there were differences in blink reflex parameters among baseline, active, and concussed athletes. Twenty-four Division I football athletes participated in this study. Routine pre-season baseline data were collected on athletes as well as assessments of their blink reflex parameters using a blink reflexometer. Significant differences were found in blink parameters between baseline and active measurements in latency, differential latency, lid velocity, log of time to open, log of number of oscillations, and log of total blink time. In addition, significant differences were found between baseline and post-head impact in latency, differential latency, log of time to open, and log of number of oscillations. In comparing head impact and active play, blink latency decreased with head impact but increased in active play and differential latency and log of number of oscillations increased with head impact but decreased in active play. The results of this study suggest that use of a blink reflexometer provides quantifiable and objective outcomes to complement the concussion assessment protocol for athletes.

Athletes are constantly trying to get an “edge” on competition. As seen in the last chapter, they will turn to dangerous drugs to get such an edge over their competitors to include steroids and doping which are used to improve performance. Dentistry may have a non-pharmacologic solution to this issue. This chapter will review the history and the future of such appliances and discuss their promise and possibilities.

Recent reports suggest the use of mouthpieces may be beneficial at improving aerobic and anaerobic exercise performance. However, the mechanisms of these reported improvements have yet to be elucidated. The purpose of this study was to explore the possible mechanisms of improved performance using the ArmourBite® mouthpiece. Using a within subject randomized treatment design, 15 experienced resistance trained males (19–26 years of age) performed 6 sets of 10 repetitions of free weight back squats at 80% of 1RM with and without a mouthpiece. Blood samples were collected before exercise, after 3 sets (Mid), immediately post (Post), 30 min post (Post-30), 60 min post (Post-60) and 120 min post (Post-120) exercise. Samples were analyzed for lactate and ELISA was used to determine cortisol. Mouthpiece use resulted in more repetitions completed without assistance (54.36 ± 0.61 vs. 53.27 ± 0.79, p = 0.046) and fewer assisted repetitions (6.73 ± 0.79 vs. 5.64 ± 0.61 repetitions, p = 0.046) compared to the control group. Lactate concentrations were lower in the treatment vs. control group at the Post (11.54 ± 2.23 vs. 13.07 ± 2.96 mmol/L, p = 0.023) Post- 30 (4.45 ± 1.94 vs. 5.41 ± 1.90 mmol/L, p = 0.021), and Post-60 (2.07 ± 0.94 vs. 2.55 ± 0.96 mmol/L, p = 0.048) sampling periods. Mouthpiece use lowered cortisol levels at Mid and Post-30 (19.39 ± 6.90 vs. 27.84 ± 14.56 μg/dL, p = 0.02 (22.91 ± 8.47 vs. 31.81 ± 10.79 μg/dL, p = 0.04). Cortisol AUC values showed significant differences within the AUC Pre-Post control and treatment (55.16 ± 23.84 vs. 41.95 ± 2.65 μg/dL, p = 0.02) groups. These data suggest that mouthpiece use may increase performance and decrease stress when used during intense resistance exercise.

The purpose of this study is to compare the accuracy of wrist-worn, consumer-grade pedometers and earbud sensor technology in quantifying energy expenditure. Nineteen participants (24.6 ± 3.1 years) performed 5 min exercise stages on a treadmill (80.5 m/min, 107.3 m/min, 134.1 m/min and 160.9 m/min) while measuring energy expenditure via the Fitbit Charge pedometer and Jabra Sport Pulse Wireless Earbuds, comparing with indirect calorimetry. Paired samples t-tests were used to calculate differences and Pearson correlations to examine associations between kcals measured from the Fitbit and Jabra earbuds from indirect calorimetry. Results indicate significant underestimations of kcals for both devices at all speeds except one (Jabra earbuds at 107.3 m/min). Moderate correlations were observed for the Fitbit at 107.3 m/min and 107.3 m/min, and 134.1 m/min for the Jabra earbuds. Both devices considerably underestimated kcals, suggesting that caution be used when incorporating such data into fitness/health goals.

Background The authors conducted a study to assess the effects of custom-fitted mouthpieces on gas exchange parameters, including voluntary oxygen consumption (VO 2 ), voluntary oxygen consumption per kilogram of body weight (VO 2 /kg) and voluntary carbon dioxide production (VCO 2 ). Methods Sixteen physically fit college students aged 18 through 21 years performed two 10-minute treadmill runs (6.5 miles per hour, 0 percent grade) for each of three treatment conditions (mouthpiece, no mouthpiece and nose breathing). The authors assigned the conditions randomly for each participant and for each session. They assessed gas exchange parameters by using a metabolic measurement system. Results The authors used analysis of variance to compare all variables. They set the significance level at α = .05 and used a Tukey post hoc analysis of treatment means to identify differences between groups. The results showed significant improvements ( P 2, VO 2 /kg and VCO 2 in the mouthpiece condition. Conclusions The study findings show that use of a custom-fitted mouthpiece resulted in improved specific gas exchange parameters. The authors are pursuing further studies to explain the mechanisms involved in the improved endurance performance exhibited with mouthpiece use. Clinical Implications Dental care professionals have an obligation to understand the increasing research evidence in support of mouthpiece use during exercise and athletic activity and to educate their patients.

Background: Lack of physical activity has been noted in breast cancer survivors and been attributed to decreased physical function. Purpose: This study assessed the effects of a moderate-to-vigorous physical exercise program on body fat percentage, maximal oxygen consumption (VO2 max), body mass index, and bone mineral density (BMD) of breast cancer survivors. Methods: Eleven stage I and II breast cancer patients, 40-65 years old, were recruited to assess VO2 max, BMD, weight, and percentage of body fat before and after an 8-week exercise (aerobic and resistance training) intervention. Results: Supervised exercise signifcantly improved aerobic capacity (+4.227 ml/kg/min; P=0.004) and increased, though not signifcantly, bone mass densities of hip (+0.433 SD units; P=0.061) and spine (+0.224 SD units; P=0.350). No significant changes were observed for body mass index (+0.0196 kg/m2; P=0.927) or body fat percentage (-0.737%; P=0.639). Discussion: Understanding how breast cancer survivors tolerate an...

Protective mouthpieces have been used in a variety of sports to decrease the risk of orofacial injury. There are limited data to suggest that mouthpiece use during exercise may also provide an ergogenic effect. The aim of the present study was to investigate the effects of 3 different mouthpiece designs-boil-and-bite (BB) mouthpiece, ethylene vinyl acetate (EVA) custom mandibular mouthpiece, and polypropylene (Poly) custom mandibular mouthpiece-on respiratory physiology parameters and compare them with results of a no-mouthpiece (NM) condition. Sixteen college-aged, recreationally fit subjects ran for 10 minutes in 4 separate trials; mouthpiece conditions were randomly assigned to each trial for all subjects. Respiratory and cardiorespiratory measures, including oxygen uptake, carbon dioxide exhalation, ventilation, heart rate, tidal volume, and respiratory rate (RR), were assessed throughout testing. A repeated-measures analysis of variance indicated that RR was significantly lower (P = 0.04) in the BB mouthpiece condition (27.92 breaths per minute [BPM]) than in the NM condition (30.63 BPM). In paired t tests between conditions, the RR demonstrated in the BB condition (27.92 BPM) was significantly lower (P = 0.04) than that of each other condition (NM, 30.63 BPM; EVA, 29.92 BPM; and Poly, 29.92 BPM). The outcomes of the present study demonstrate that the use of the BB mouthpiece decreased RR during exercise. The differences cited between conditions may be attributed to the design of the mouthpiece and its mandibular placement as well as the activity of the genioglossus muscle. However, future studies should assess these parameters to determine the plausibility of these theories.

The aim of this study was to assess the relationships between human muscle fiber hypertrophy, protein isoform content, and maximal Ca2+-activated contractile function following a short-term period of resistance exercise training. Six male subjects (age 27 ± 2 yr) participated in a 12-wk progressive resistance exercise training program that increased voluntary lower limb extension strength by >60%. Single chemically skinned fibers were prepared from pre- and posttraining vastus lateralis muscle biopsies. Training increased the cross-sectional area (CSA) and peak Ca2+-activated force (Po) of fibers containing type I, IIa, or IIa/IIx myosin heavy chain by 30–40% without affecting fiber-specific force (Po/CSA) or unloaded shortening velocity (Vo). Absolute fiber peak power rose as a result of the increase in Po, whereas power normalized to fiber volume was unchanged. At the level of the cross bridge, the effects of short-term resistance training were quantitative (fiber hypertrophy and proportional increases in fiber Poand absolute power) rather than qualitative (no change in Po/CSA, Vo, or power/fiber volume).

Research has suggested mouthpiece use during exercise results in an increase in muscle strength and endurance. However, the research is difficult to replicate, and the methodology suggested measures that were too subjective to determine a mouthpiece effect. Thus, the purpose of this study was to use an objective measure to determine a possible physiological mechanism occurring during and after exercise with mouthpiece use. A within-subjects design was used in which 28 division I football players, aged 18-22 years, performed 2 identical bouts of a 1-hour intense resistance exercise, with each subject being randomly assigned the use of a custom-fit mouthpiece either during the first or second session. During both exercise sessions, saliva was analyzed for cortisol at the following time points: pre-exercise, 25, 45, and 60 minutes of exercise, and 10 minutes postexercise. The results revealed a significant difference in cortisol levels with the use of a mouthpiece vs. no mouthpiece (p = 0.019) at 10 minutes postexercise. Additionally, although the expected increase in cortisol levels from pre to 10 minutes postexercise was present in the no-mouthpiece group (p = 0.01), no such increase was observed in the mouthpiece group. These observations are most likely because of the decrease in cortisol from post to 10 minutes post (p = 0.04) in the mouthpiece group. These data demonstrate that although cortisol continued to increase in the no-mouthpiece session, there was a significant decrease in cortisol in the no-mouthpiece condition 10 minutes postexercise.

Research has described the use of mouthpieces not only in preventing oral-facial injuries, but linking use to improvements in muscular strength and endurance. However, the mechanisms by which these improvements occur have not been elucidated. The purpose of this study was to understand possible physiological explanations for improvements in exercise performance with the use of a mouthpiece. Specifically, this study focused on differences in lactate levels after 30 minutes of endurance exercise with and without a mouthpiece. In addition, computed tomography (CT) scans were taken of the cross-sectional area of the oropharynx in each participant (N = 10) with and without a mouthpiece. CT scans showed a significant difference in mean width (28.27 mm with the mouthpiece vs 25.93 mm without the mouthpiece, P = .029) and an increase in mean diameter with a mouthpiece (12.17 mm vs 11.21 mm, P = .096). Lactate levels were lowered with the mouthpiece at 1.86 mmol/L vs 2.72 mmol/L without mouthpiece. This research suggests that there is an improvement in endurance performance that may be linked to improved airway openings resulting from the use of a mouthpiece. Future studies should continue to clarify the possible mechanisms for these exercise outcomes as well as to understand the optimal mandibular advancement to elicit these exercise improvements.

Studies in exercise science have suggested that the use of a mouthpiece can improve performance, and these improvements may be linked to an enhancement in temporomandibular joint (TMJ) positioning. Studies have suggested that by improving TMJ positioning, there is improved blood flow in the area of the TMJ. Changes in TMJ positioning may be improved with an oral device. The purpose of this study was to determine if there were improvements in auditory and visual reaction time with the use of a boil and bite mouthpiece. Using a BIOPAC system, study participants (N = 34) were asked to respond to an auditory signal during 40 trials. In the visual reaction time test, participants (N = 13) were assessed on how quickly they responded to a computer cue for a total of 30 trials. Auditory results showed a significant improvement with the use of a mouthpiece (241.44 ms) vs without a mouthpiece (249.94 ms). Visual results showed that participants performed slightly better with the mouthpiece (285.55 ms) vs without the mouthpiece (287.55 ms). These findings suggest that the use of mouthpiece positively affects visual and auditory reaction time, which is a vital aspect to optimal sport and exercise performance. Future studies should continue to shed light on possible reasons for the improvements in auditory and visual reaction time with the use of a mouthpeice. In addition, future studies should further illuminate what, if any, connection these improvements have with enhanced TMJ positioning.

Apoptosis of retinal ganglion cells (RGCs) impairs vision in glaucoma patients. RGCs are also degenerated in multiple sclerosis (MS), resulting in loss of visual perception in MS patients. We examined the involvement of calpain and caspase cascades in apoptosis of the rat retinal ganglion cell line RGC-5 following 24 h of exposure to 250 nM ionomycin (IMN) or 300 units/ml interferon-gamma (IFN-gamma) and then evaluated functional neuroprotection with 2 microM calpeptin (CP, a calpain-specific inhibitor). Morphological and biochemical features of apoptosis were detected in RGC-5 cells following exposure to IMN or IFN-gamma. Fura-2 assay determined significant increases in intracellular free [Ca2+] following exposure to IMN or IFN-gamma. Pretreatment with CP for 1 h prevented Ca2+ influx, proteolytic activities, and apoptosis in RGC-5 cells. Western blot analyses showed an increase in activities of calpain and caspase-12, upregulation of Bax:Bcl-2 ratio, release of cytochrome c from mitochondria, and increase in caspase-9 and caspase-3 activities during apoptosis. Increased caspase-3 activity was also confirmed by a colorimetric assay. Activation of caspase-8 and cleavage of Bid to tBid in RGC-5 cells following exposure to IFN-gamma indicated co-operation between extrinsic and intrinsic pathways of apoptosis. Patch-clamp recordings showed that pretreatment with CP attenuated apoptosis and maintained normal whole-cell membrane potential, indicating functional neuroprotection. Taken together, our results demonstrated that Ca2+ overload could be responsible for activation of calpain and caspase cascades leading to apoptotic death of RGC-5 cells and CP provided functional neuroprotection.

Purpose: We compared the functional properties of muscle fibers from two groups of subjects that differed widely in their training history to investigate whether long-term resistance exercise alters the intrinsic contractile properties of skeletal muscle fibers. Methods: Vastus lateralis muscle biopsies were obtained from six sedentary males (NT group, age = 23 ′ 1 yr) and six males who had participated in regular resistance exercise training over the preceding 7.6 ′ 1.6 yr (RT group, 22 ′ 1 yr). Chemically skinned muscle fiber segments were activated with a saturating free [Ca 2 + ] to quantify fiber peak Ca 2 + -activated force (P o ), unloaded shortening velocity (V o ), and peak power. Fiber segment myosin heavy chain (MHC) isoform content was identified by gel electrophoresis. Results: Slow and fast fibers from the RT group were larger in CSA and produced greater absolute P o and absolute peak power in comparison with fibers from the NT group. However, these differences were no longer evident after P o and peak power were normalized to fiber CSA and fiber volume, respectively. V o /fiber length was dependent on fiber MHC content but independent of training status. Conclusion: Fiber hypertrophy was sufficient to account for intergroup differences in P o and peak power of slow and fast fibers. There was no evidence that the intrinsic contractility of slow or fast fibers, as evaluated by force, shortening velocity, and power normalized to the appropriate fiber dimensions, differed between RT and NT groups.

Vastus lateralis muscle biopsies were obtained from six individuals with multiple sclerosis (MS) having an Expanded Disability Status Score of 4.75 +/- 0.28, and from six age- and gender-matched individuals without MS. Biopsies from the MS group showed fewer fibers (31 +/- 4 vs. 46 +/- 4%) containing the type IIa myosin heavy chain (MHC) isoform exclusively. However, the percentage of fibers coexpressing type IIa and IIx MHC increased in direct proportion with MS disability status. The average unloaded shortening velocity of skinned fibers containing type I or IIa MHC did not differ between subject groups. Peak Ca(2+)-activated force was 11-13% lower in fibers from the MS group due to atrophy (type I and IIa fibers) and reduced specific force (type I fibers). Increasing intracellular inorganic phosphate (0-30 mM) or hydrogen ion (pH 7.0-6.2) reduced Ca(2+)-activated force in a manner that was independent of MS status. Thus, fibers from the MS group showed a subtle shift in fast MHC isoform coexpression and a modest reduction in cross-bridge number, density, or average force, with no change in maximal cross-bridge cycling rate or susceptibility to intracellular metabolites. These changes explain part of the muscle weakness and fatigue experienced by individuals with MS.

We tested the hypothesis that cross-bridge mechanisms of contraction differed in early postmenopausal women who did or did not receive hormone replacement therapy (HRT). Vastus lateralis biopsies were obtained from 17 postmenopausal women (49–57 years old), 8 of whom were on HRT for the previous 24 ± 5 months and 9 of whom were never on HRT. Electrophoresis and enzyme histochemistry revealed that fiber myosin heavy chain (MHC) isoform distribution, the cross-sectional area (CSA) of slow and fast fibers, and the relative CSA occupied by each, were similar for HRT and non-HRT groups. Single permeabilized fibers containing type IIa MHC had greater Ca2+-activated peak specific force, unloaded shortening velocity, and peak power than fibers containing type I MHC, but in all cases the values for HRT and non-HRT groups were similar. In this cross-sectional study, we found no evidence that Ca2+-activated fiber function, MHC isoform distribution, or relative CSA occupied by slow and fast fibers differed between HRT and non-HRT groups.