Breathing Resistance Research Articles

Polymer/MOF-derived multilayer fibrous membranes for moisture-wicking and efficient capturing both fine and ultrafine airborne particles

Particulate matter (PM)-induced air pollution has become a serious threat to public health in many regions. There is, therefore, a need for development of advanced respirator materials that can efficiently capture PM and also exhibit both low breathing resistance and good moisture wicking properties to ensure physiological comfort of the wearers. Herein, we report a new type of multilayer membranes that exhibit excellent filtration efficiencies for PM of various sizes, low air resistance and good directional moisture transport properties. We incorporated a type of metal-organic framework, ZIF-8, into polyacrylonitrile (PAN) to prepare microfibers with high surface roughness, and alternatingly stacked layers of rough microfibers with layers of PAN nanofibers via electrospinning, resulting in multi-level structured membranes. Moreover, subsequent acid and base treatments could not only tailor the hydrophilicity of fiber surfaces, but also induce multiscale surface roughness, facilitating both moisture wicking and PM adsorption. This allowed us to construct a unique multilayer membrane composed of a super-hydrophilic outer layer made of PAN fibers with multiscale surface roughness, a hydrophilic composite intermediate layer consisting of porous PAN-ZIF-8 microfibers and PAN nanofibers, and a hydrophobic polystyrene fibrous inner layer, which could offer excellent directional moisture transport performance and a high water vapor transmission rate of 10.56 kg m−2 d−1 due to strong capillary force and push-pull effect. More importantly, benefiting from the large specific surface area, rough fiber surface, and hierarchical pore structure, the membrane exhibits high removal efficiencies of 99.973% for 0.3-μm particles and ≧99.99% for particles of other sizes, including the more harmful ultrafine particles, at a low pressure drop of 80.1 Pa. Moreover, the multilayer composite filter still maintains a high removal efficiency of 99.951% after continuous air purification for 48 h in a high PM2.5 concentration (>300 μg m−3) environment. These make such membranes promising high-performance filtration media for respirator applications.

Impact of structural features on dynamic breathing resistance of healthcare face mask

In order to provide an overall evaluation and characterization of the comfort sensation and performance of face mask related to breathing resistance for healthcare in fog and haze weather, and address the influence of structural features on breathing resistance properties, an experimental set-up was developed, which was able to continuously change the direction and rate of air flow and the breathing frequency to simulate the dynamic breathing process during the actual wearing of face mask. The dynamic changes of airflow rate and the breathing resistance were acquired by a virtual instrument (VI) system and a microelectronics system. Six evaluation indices were defined for the dynamic performance and comfort sensation of face mask, derived from the source data of dynamic breathing resistance. Twelve types of face masks from different department stores with different features such as shape, respiratory valve, brand, main materials and protection level were tested using the experimental set-up. The one-way ANOVA analysis was carried out to identify the significance of the differences of the indices among the test masks. The results showed that each evaluation index was significantly different (P < 0.05) among different test masks. The change rate of breathing resistance could be obtained using the dynamic measurement of breathing resistance and could be applied for the dynamic performance evaluation of face mask compared with the static measurement of breathing resistance under constant airflow rate. The influences of structural features such as respiratory valve, shape and main materials on breathing resistance were evaluated and analyzed. The face masks with respiratory valve had lower change rate of breathing resistance. Moreover, the cup type mask had lower change rate of breathing resistance than the folding mask. Furthermore, the cotton mask had lower change rate of breathing resistance than the nonwoven fabric mask.

GEP-based predictive modeling of breathing resistances of wearing respirators on human body via sEMG and RSP sensors

PurposeBreathing resistance is the main factor that influences the wearing comfort of respirators. This paper aims to demonstrate the feasibility of using the gene expression programming (GEP) for the purpose of predicting subjective perceptions of breathing resistances of wearing respirators via surface electromyography (sEMG) and respiratory signals (RSP) sensors.Design/methodology/approachThe authors developed a physiological signal monitoring system with a specific garment. The inputs included seven physical measures extracted from (RSP) and (sEMG) signals. The output was the subjective index of breathing resistances of wearing respirators derived from the category partitioning-100 scale with proven levels of reliability and validity. The prediction model was developed and validated using data collected from 30 subjects and 24 test combinations (12 respirator conditions × 2 motion conditions). The subjects evaluated 24 conditions of breathing resistances in repeated measures fashion.FindingsThe results show that the GEP model can provide good prediction performance (R2 = 0.71, RMSE = 0.11). This study demonstrates that subjective perceptions of breathing resistance of wearing respirators on the human body can be predicted using the GEP via sEMG and RSP in real-time, at little cost, non-invasively and automatically.Originality/valueThis is the first paper suggesting that subjective perceptions of subjective breathing resistances can be predicted from sEMG and RSP sensors using a GEP model, which will remain helpful to the scientific community to start further human-centered research work and product development using wearable biosensors and evolutionary algorithms.

Evaluation on the Wear Fit and Activity of Emergency Escape Breathing Devices for Ship Accidents

선박 운항 중 화재나 사고 시에 선박 내부의 복잡한 구조나 침수로 인해 갑판으로의 신속한 피난이 어려울 경우 유해가스나 산소 부족에 대응하기 위해서는 비상탈출용 호흡구난장비가 필수적이다. 최근 국내에서도 비상탈출호흡 구가 개발 보급되고 있으나, 기본 성능만 만족할 뿐 실제 사용시의 착용성 및 활동성에 대한 평가 사례가 없어 그효용성에 대해 의혹이 크다. 본 연구에서는 선박사고에 적합한 비상탈출호흡구에 대한 착용성 및 활동성 평가 항목을 제반 국제 기준으로부터 도출하였고, 개방식과 폐쇄식 각각의 국산 제품 샘플에 대한 평가를 수행하였다. 개방식은 시인성, 착용시간, 호흡저항 및 호스 걸림 부분에서, 폐쇄식은 정화통 방해, 무게 불균형, 호흡백 시야 가림 부분에서 개선이 필요한 것으로 평가되었다. ABSTRThe use of emergency escape breathing devices (EEBD) is strongly required to protect against toxic gas or flooding caused by ship fires or accidents. Recently developed domestic EEBD products only satisfy the basic performance requirements, but no wear fit and activity performance evaluation has been done for real usage. In this study, the global level test requirements for wear comfort and activity of EEBDs were developed and the open and closed type of domestic EEBD products were evaluated. Poor visibility, longer wear time, breathing resistance, and hose obstruction in an open type and canister obstruction, weight unbalance, and an invisible black breathing bag in the closed type EEBD were estimated to be the main problems that need to be improved.

Within-breath changes in respiratory system impedance in children with cystic fibrosis.

The aim of this study was to assess within-breath respiratory system impedance by the forced oscillation technique (FOT) in children with cystic fibrosis (CF) and relate it to the underlying lung disease. Thirty-three children with CF (median [range] age 12.0 [6-17] years) underwent FOT at 8 Hz during tidal breathing, multiple breath nitrogen washout (LCI), spirometry (FEV1), body plethysmography (RV/TLC), and magnetic resonance imaging (MRI). FOT outcomes included: mean inspiratory, expiratory, and whole breath resistance (R8INSP , R8EXP , R8TOT ) and reactance (X8INSP , X8EXP , X8TOT ), and the differences between X8INSP and X8EXP (ΔX8). Morphological changes were evaluated by MRI using CF-specific morphological scores. Spearman correlation was performed to examine the correlation between FOT indices and other parameters. FEV1 was negatively correlated with R8EXP (r = -0.52, P = 0.002) and ΔX8 (r = -0.55, P = 0.001), and positively correlated with and X8EXP (r = 0.56, P < 0.001). RV/TLC was positively correlated with R8EXP (r = 0.43, P = 0.013), and ΔX8 (r = 0.54, P = 0.001) and negatively correlated with X8EXP (r = -0.54, P = 0.001). We found poor correlation between FOT parameters and LCI and no correlation between FOT parameters and MRI scores. In children with CF, changes in within-breath FOT parameters are consistent with peripheral obstruction and dynamic airway compression, while they are not associated with ventilation heterogeneities and morphological alterations.

Respiratory muscle dysfunction and chronic obstructive pulmonary disease.

The review presents literature data on the problem of respiratory muscle (RM) dysfunction in patients with chronic obstructive pulmonary disease (COPD). In the development of RM dysfunction, both local and systemic factors of the pathogenesis of COPD are important. Local factors are associated with lung remodelling and the need to overcome RM excessive breathing resistance, which increases the intensity of their work, contributes to the development of hypertrophy and insufficiency. Chronic systemic inflammation, oxidative stress, excessive proteolysis and other systemic manifestations of COPD change the metabolism and structural and functional organisation of RM. Low nutritional status, increasing protein-energy deficiency, electrolyte imbalance, endocrine disorders against the background of progressive respiratory insufficiency and tissue hypoxia contribute to the development of RM weakness. The combination of COPD, acute disorders of cerebral circulation and chronic heart failure sharply worsens the function of RM and the prognosis of comorbid diseases. Also, the dysfunction of RM in patients with COPD is significantly aggravated at the age of senility. The review discusses the possibilities of pharmacological correction of RM dysfunction and other clinical aspects of this problem.

Validity and reliability of rating scales for subjective breathing resistance of wearing respirators

Purpose Investigating the subjective breathing resistance of wearing respirators requires a valid and reliable technique to measure breathing resistance. The purpose of this study is to test the validity and reliability of several rating scales and select the best for investigation of breathing resistance. Design/methodology/approach The authors designed three scales, that is, BRX scale, CP-100 scale and RVAS scale, and 30 subjects were separated into three groups, each group with a different scale. They sat for 5 min and walked for 5 min while wearing three models of respirators. After each trial, subjects were asked to complete subjective ratings of breathing resistance. Reliability was examined by the coefficient of Cronbach’s α, and validity was examined through content validity, discriminant validity and criterion validity. Generally, subjects were capable of reporting their sensation of breathing resistance by using the rating scale technique. However, the accuracy of rating strongly depended upon the properties of the scale. Findings The CP-100 scale was found to be highly reliable and most valid for rating subjective breath resistance. The validated CP-100 scale is very sensitive and accurate. Originality/value This is the first paper to select the best subjective scale for investigation of breathing resistance of respirators. The CP-100 scale will find wide applications in subjective breathing resistance evaluation for the use of respirators in industrial benchmarking activities. It will introduce the human factor engineering into the respirator manufacturing to improve the comfort of respirators.

Autonomic Nervous System Dysfunction in Pediatric Sepsis.

The autonomic nervous system (ANS) plays a major role in maintaining homeostasis through key adaptive responses to stress, including severe infections and sepsis. The ANS-mediated processes most relevant during sepsis include regulation of cardiac output and vascular tone, control of breathing and airway resistance, inflammation and immune modulation, gastrointestinal motility and digestion, and regulation of body temperature. ANS dysfunction (ANSD) represents an imbalanced or maladaptive response to injury and is prevalent in pediatric sepsis. Most of the evidence on ANSD comes from studies of heart rate variability, which is a marker of ANS function and is inversely correlated with organ dysfunction and mortality. In addition, there is evidence that other measures of ANSD, such as respiratory rate variability, skin thermoregulation, and baroreflex and chemoreflex sensitivity, are associated with outcomes in critical illness. The relevance of understanding ANSD in the context of pediatric sepsis stems from the fact that it might play an important role in the pathophysiology of sepsis, is associated with outcomes, and can be measured continuously and noninvasively. Here we review the physiology and dysfunction of the ANS during critical illness, discuss methods for measuring ANS function in the intensive care unit, and review the diagnostic, prognostic, and therapeutic value of understanding ANSD in pediatric sepsis.

Microorganism-ionizing respirator with reduced breathing resistance suitable for removing airborne bacteria

In this paper, we have demonstrated the feasibility of using microorganism-ionizing respirators with reduced breathing resistance to remove airborne bacteria. Using a miniaturized corona ionizer and two pairs of separator electrodes, airborne bacteria were ionized and removed from the airflow. Two microorganism-ionizing respirator designs were experimentally evaluated with flow rates ranging from ∼10 to 20 L/min and yielded airborne bacterial removal efficiencies of ∼75%–100%. Further, they were in close agreement with the analytical airborne particle removal efficiencies, at a similar range of flow rates. These flow rates also correspond to the breathing rates of standing and walking adults. More importantly, the breathing resistance could be reduced by more than 50% for flow rates of ∼200 L/min. Using manganese (IV) oxide coated mesh, the ozone concentration in the air outflow was reduced to less than 0.1 ppm, at a flow rate of ∼20 L/min, thus enabling safe use. The power consumption was less than 1 W.

Assessing the breathing resistance of filtering-facepiece respirators in Polish coal mines: A survey and laboratory study

Hard coal miners most commonly use filtering-facepiece respirators to protect themselves from hazardous air particles. Prolonged exposure to coal mine dust is the cause of various pulmonary diseases, particularly coal workers' pneumoconiosis. This article presents the results of an assessment of the breathing resistance of filtering-facepiece respirators (FFRs), which are commonly used in underground hard coal mine workings. The results include survey studies and laboratory examinations of the effect of an increase in dust and moisture mass on the breathing resistance of FFRs. The survey was conducted among 150 respondents, who represented three groups of miners: workers who directly handle the material, workers who handle the transport of materials, and technical mining staff. The age of the employees was 21–50 years. In the study, we obtained the miners' opinions on the relevance of the application of respirators, their structural strength and the maximum use period in the arduous conditions of the mine. The laboratory examination results show that both dust and the moisture absorbed by the FFRs considerably affect the increase in breathing resistance. For this reason the time of use of the respirators in underground coal mining conditions is much shorter than expected.Our study may result in developing technologies to produce new and improved filtering materials and respiratory protection equipment in the mining industry, which will better secure miners against the harmful effect of mine dust.

Sleep-disordered Breathing in Uncontrolled Blood Pressure: Our Experience

Introduction: Sleep-disordered breathing is one of the greatest health problems. It comprises of obstructive sleep apnea, central sleep apnea, periodic breathing, and upper airway resistance syndrome. There are several studies reporting association of uncontrolled blood pressurewith individuals having sleep disordered breathing. Data regarding this were sparse in developing countries. Therefore this study was performed to find out the sleep-disordered breathing among uncontrolled hypertensive patients.Materials and Methods: Study was performed from January, 2014 to January, 2017 in sleep center in Kathmandu, Nepal. Patient with uncontrolled BP were included. Uncontrolled BP was defined as blood pressure&gt;130/80mmHg not on intensive antihypertensive regimen and resistant elevated BP was defined as blood pressure &gt;130/80 mmHg despite intensive antihypertensive regimen. These patients were subjected for polysomnography.Results: Three hundred patients were selected out of which 250 patients with uncontrolled blood pressure were included. They were subjected for overnight polysomnography. Among them, 70patients (28%)were found to have mild obstructive sleep apnea, 20 patients had moderate obstructive sleep apnea (8%)&amp;15 had severe obstructive sleep apnea (6%).Conclusions: This study concludes that those individuals having uncontrolled blood pressure has obstructive sleep apnea and these individuals have to undergo polysomnography.Nepalese Medical Journal, vol.1, No. 1, 2018, page: 36-38

Inspiratory and expiratory resistance cause right-to-left bubble passage through the foramen ovale.

A patent foramen ovale (PFO) is linked to increased risk of decompression illness in divers. One theory is that venous gas emboli crossing the PFO can be minimized by avoiding lifting, straining and Valsalva maneuvers. Alternatively, we hypothesized that mild increases in external inspiratory and expiratory resistance, similar to that provided by a SCUBA regulator, recruit the PFO. Nine healthy adults with a Valsalva‐proven PFO completed three randomized trials (inspiratory, expiratory, and combined external loading) with six levels of increasing external resistance (2–20 cmH2O/L/sec). An agitated saline contrast echocardiogram was performed at each level to determine foramen ovale patency. Contrary to our hypothesis, there was no relationship between the number of subjects recruiting their PFO and the level of external resistance. In fact, at least 50% of participants recruited their PFO during 14 of 18 trials and there was no difference between the combined inspiratory, expiratory, or combined external resistance trials (P > 0.05). We further examined the relationship between PFO recruitment and intrathoracic pressure, estimated from esophageal pressure. Esophageal pressure was not different between participants with and without a recruited PFO. Intrasubject variability was the most important predictor of PFO patency, suggesting that some individuals are more likely to recruit their PFO in the face of even mild external resistance. Right‐to‐left bubble passage through the PFO occurs in conditions that are physiologically relevant to divers. Transthoracic echocardiography with mild external breathing resistance may be a tool to identify divers that are at risk of PFO‐related decompression illness.

Computer vision-based objective evaluation of increase in breathing resistances of respirators on human subjects

The purpose of this study was to evaluate objectively the impact of wearing respirators on breathing resistances of actual human subjects. We designed a monitor of the nasal airflow, which was composed of a full facepiece mask, a pipe for gathering nasal airflow, a monitoring line and a camera. A total of 5 normal adult volunteers were recruited in this study. Wearing the monitor, the subjects were required to sit for 1 min and walk for 1 min during wearing eight different models of respirators and without a respirator. Subsequently, the swing video of the monitoring line was collected by the camera during each breath of the subjects. The mean value of maximum swing angles of the monitoring line and the swing angle ratio were calculated through the image processing of the experimental videos. The experimental results show that the swing angle ratio during exhalation and inhalation are effective for representing exhalation resistances and inhalation resistances respectively. This is the first reported study that combines computer vision and the self-developed nasal airflow monitor to demonstrate quantitatively and objectively the exhalation resistances and inhalation resistances with the use of different respirators on actual human subjects.

The Physiological Effects of Combined Training with Breathing Resistance and Sustained Physical Exertion in Healthy Young Adults

Purpose: The aim of the present study was to describe the physiological effects of a combined training with breathing resistance and sustained physical exertion (CBS) program, which is a respiratory muscle training program designed to improve respiratory function and cardiorespiratory endurance, in young adults.Methods: Pre-and post-intervention measurements were comparatively examined between a group that completed an endurance exercise training program combined with a breathing resistance component (CBS group) and a group that underwent an endurance exercise training program only (control group). Data for these participants were analyzed together with similar data obtained in a previous study, where the effects of the CBS program on the respiratory and circulatory systems of nine healthy young subjects were evaluated with preliminary position of present research. The participants of the present study additionally underwent measurements related to respiratory muscle endurance. All participants were healthy young men and women.Results: In total, 18 participants were analyzed. After the 6-week program, the maximum oxygen uptake and peak ventilatory threshold in the CBS group showed a significant improvement relative to the baseline measurements. The maximal voluntary ventilation and respiratory muscle endurance capacity also exhibited an improvement.Conclusions: The results of this study indicate that our CBS program improves respiratory function more effectively than conventional training programs. Furthermore, they strongly support the findings of our previous study, where it was reported that CBS improves cardiorespiratory endurance more effectively than conventional training programs. Condensed AbstractWe described the physiological effects of a combined training with breathing resistance and sustained physical exertion program in healthy young adults. The obtained data were combined with existing comparable data. We found that the improvements in respiratory muscle function and cardiorespiratory endurance were greater with our combined program than with conventional programs.

Cardiovascular and Cutaneous Responses to the Combination of Alcohol and Soft Drinks: The Way to Orthostatic Intolerance?

Aim: Acute ingestion of alcohol is often accompanied by cardiovascular dysregulation, malaise and even syncope. The full hemodynamic and cutaneous responses to the combination of alcohol and sugar (i.e., alcopops), a common combination in young people, and the mechanisms for the propensity to orthostatic intolerance are not well established. Thus, the purpose of this study was to evaluate the cardiovascular and cutaneous responses to alcopops in young subjects.Methods: Cardiovascular and cutaneous responses were assessed in 24 healthy young subjects (12 men, 12 women) sitting comfortably and during prolonged active standing with a 30-min baseline and 130 min following ingestion of 400 mL of either: water, water + 48 g sugar, water + vodka (1.28 mL.kg−1 of body weight, providing 0.4 g alcohol.kg−1), water + sugar + vodka, according to a randomized cross-over design.Results: Compared to alcohol alone, vodka + sugar induced a lower breath alcohol concentration (BrAC), blood pressure and total peripheral resistance (p < 0.05), a higher cardiac output and heart rate (p < 0.05) both in sitting position and during active standing. In sitting position vodka + sugar consumption also led to a greater increase in skin blood flow and hand temperature (p < 0.05) and a decrease in baroreflex sensitivity (p < 0.05). We observed similar results between men and women both in sitting position and during active standing.Conclusion: Despite lower BrAC, ingestion of alcopops induced acute vasodilation and hypotension in sitting position and an encroach of the hemodynamic reserve during active standing. Even if subjects did not feel any signs of syncope these results could be of clinical importance with higher doses of alcohol or if combined to other hypotensive challenges.

Obstructive sleep apnea and rhonchopathy are associated with downregulation of trefoil factor family peptide 3 (TFF3)-Implications of changes in oral mucus composition.

Study objectivesTrefoil factor family (TFF) peptides belong to the family of mucin-associated peptides and are expressed in most mucosal surfaces. TFF peptides carry out functions such as proliferation and migration enhancement, anti-apoptosis, and wound healing. Moreover, TFFs are associated with mucins and interact with them as “linker peptides”, thereby influencing mucus viscosity.To test the hypothesis that in rhonchopathy and obstructive sleep apnea (OSA) changes occur in the expression of TFF3 and -2 that could contribute to changes in mucus viscosity, leading to an increase in upper airway resistance during breathing.MethodsRT-PCR, Western-blot, immunohistochemistry and ELISA were performed to detect and quantify TFF3 and -2 in uvula samples. In addition, 99 saliva samples from patients with mild, moderate or severe OSA, as well as samples from rhonchopathy patients and from healthy volunteers, were analyzed by ELISA.ResultsTFF3 was detected in all uvula samples. Immunohistochemistry revealed a subjectively decreasing antibody reactivity of the uvula epithelia with increasing disease severity. ELISA demonstrated significantly higher TFF3 saliva protein concentrations in the healthy control group compared to cases with rhonchopathy and OSA. Predisposing factors of OSA such as BMI or age showed no correlation with TFF3. No significant changes were observed with regard to TFF2.ConclusionsThe results suggest the involvement of TFF3 in the pathogenesis of rhonchopathy and OSA and lead to the hypothesis that reduction of TFF3 production by the epithelium and subepithelial mucous glands of the uvula contribute to an increase in breathing resistance due to a change in mucus organization.

POSSIBILITIES OF THE USE OF WORKING SELF-CONTAINED BREATHING APPARATUSES FILTRATING CARBON MONOXIDE IN THE PRACTICE OF MINE RESCUE SERVICES

Abstract In the current practice of the Mining Rescue Service of the Czech Republic, since 2005, the insulated overpressure regenerative breathing apparatuses with a closed circuit and supply of medicinal oxygen are used as the backbone working breathing apparatuses. At the end of the year 2010, the compressed-air breathing apparatuses were introduced into the practice of the Mining Rescue Service of the Czech Republic, which, in precisely defined types of mine rescue service interventions and under precisely defined conditions, can replace the aforementioned backbone working insulated overpressure regenerative breathing apparatuses. Recently, mining rescue services in deep coal mines have been more and more often conducted under conditions of an irrespirable mine atmosphere containing high concentrations of carbon monoxide, but at the same time containing sufficient oxygen for the breathing physiology of mine rescuer (for example, interventions dealing with the disposal of machinery under conditions of occurrence of endogenous mining fire of coal). This fact, after a long time, has resumed again the discussion of miners' rescue experts about whether it would be possible to implement the use of breathing apparatuses filtrating carbon monoxide into practice by the Mining Rescue Services of the Czech Republic in order to ensure a sufficient level of safety for mining rescuers even in an unexpected and rapid decline of the oxygen amount in the mine air at the site of the mine rescue service. The benefit of the breathing apparatuses filtrating carbon monoxide is their significantly lower weight, long protection period and also significantly smaller dimensions and design variability of the device. The disadvantages are higher breathing resistances and a higher temperature of the air mass inhaled from the breathing apparatus filtrating carbon monoxide.

Breathing resistance in automated metabolic systems is high in comparison with the Douglas Bag method and previous recommendations

The purpose of this study was to investigate the resistance to breathing in metabolic systems used for the distribution and measurement of pulmonary gas exchange. A mechanical lung simulator was used to standardize selected air flow rates ([Formula: see text], L/s). The delta pressure (Δ p, Pa) between the ambient air and the air inside the equipment was measured in the breathing valve’s mouthpiece adapter for four metabolic systems and four types of breathing valves. Resistance for the inspiratory and expiratory sides was calculated as RES = (Δ p/[Formula: see text]) Pa/L/s. The results for resistance showed significant ( p &lt; 0.05) between-group variance among the tested metabolic systems, breathing valves, and between most of the completed [Formula: see text]. The lowest resistance among the metabolic systems was found for a Douglas Bag system which had approximately half of the resistance compared to the automated metabolic systems. The automated systems were found to have higher resistance even at low [Formula: see text] in comparison with previous findings and recommendations. For the hardware components, the highest resistance was found for the breathing valves, while the lowest resistance was found for the hoses. The results showed that resistance in metabolic systems can be minimized through conscious choices of system design and hardware components.

Year in review 2016: Interstitial lung disease, pulmonary vascular disease, pulmonary function, paediatric lung disease, cystic fibrosis and sleep.

Year in review 2016: Interstitial lung disease, pulmonary vascular disease, pulmonary function, paediatric lung disease, cystic fibrosis and sleep.

Assessment of Sprint Performance Following the Use of Resistance Training Masks During Dynamic Warm-Up

A proposed method of increasing warm-up intensity without inducing muscular fatigue is using a respiratory training mask to provide breathing resistance. Despite the lack of research-based evidence and equivocal anecdotal evidence, this particular warm-up strategy does appear to be of increasing popularity among both athletes and active individuals. PURPOSE: The purpose of this study was to investigate sprint performance following the use of training masks during dynamic warm-up in Division I American football athletes. METHODS: Seventeen male (mean±SD: age = 17.94±.75 years, weight = 104.43±23.02 kg, height 184.93±7.06 cm) NCAA Divison I, American football athletes from a Midwestern university were recruited to participate in this study. Athletes were informed of risks, and completed 3 testing sessions separated by 7 days each. All testing sessions took place at the same time of day on artificial turf in the university’s indoor training facility. Testing sessions began with a warm-up (WU) under the instruction of a member of the university’s Strength and Conditioning staff. The WU consisted of dynamic exercises targeting the lower body musculature. During the initial visit, participants completed the dynamic WU and tested on 5x10-meter sprints without a respiratory training mask and all data collected during the initial visit were used to establish baseline measurements. During the second and third visits, participants were randomly selected to complete the WU with the respiratory training mask set to simulate an altitude 3,657.6 (EXP) m or 914.4 m (SHAM). Upon completion of the WU, participants removed the mask and performed 5 × 10-meter sprints. A one-way repeated measures analysis of variance (ANOVA) design was used to assess differences between control and experimental results. All statistical analyses were performed using SPSS (Version 21.0 for Windows; SPSS, Chicago, Illinois) with statistical significance set a p < .05. RESULTS: No significant differences were found between control, sham, and experimental measures (P = 0.7-0.874). CONCLUSION: These findings suggest that the use of respiratory training masks during WU does not improve sprint times in Division I football athletes.