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Aims: To generate reference values for two inspiratory muscle endurance (IME) protocols in healthy children and adolescents., Materials and Methods: This is an observational, cross-sectional study, in healthy children and adolescents from 4 to 18 years of age. Weight, height, maximal inspiratory pressure (MIP) and IME were measured using two protocols. A fixed load of 30% of MIP with a 10% increment every 2 minutes was used in the incremental threshold loading protocol. As for the maximal loading protocol, a fixed load of 70% of MIP was used and the time limit (Tlim) achieved until fatigue was measured., Results: A total of 462 participants were included, 281 corresponding to the incremental loading protocol and 181 to maximal loading. There were moderate and positive correlations between IME and age, MIP, weight and height in the incremental threshold loading. However, the regression model demonstrated that MIP and age were the best variables to predict the IME. Otherwise, weak and positive correlations with age, weight and height were found in the maximal loading. Only age and height influenced endurance in the regression model. The predictive power (r2) of the incremental threshold loading protocol was 0.65, while the maximal loading was 0.15. The reproducibility measured by the intraclass correlation coefficient (ICC) was higher in the incremental loading (0.96) compared to the maximal loading test (0.69)., Conclusion: IME in healthy children and adolescents can be explained by age, height and MIP. The incremental threshold loading protocol showed more reliable results and should be the model of choice to evaluate IME in the pediatric age group., Competing Interests: The authors have declared that no competing interests exist.

Objective: To compare inspiratory muscle function (strength and endurance) between asthmatics and healthy controls, and the influence of age, nutritional status and physical activity on them., Methods: This is a cross-sectional study. Asthmatic and healthy subjects, aged 6 to 18 years old, recruited from two public schools in Southern Brazil were included in the study. Asthmatic subjects were selected using the criteria presented by the International Study on Asthma and Allergies in Children and control subjects based on the absence of respiratory symptoms. Anthropometric data was measured, body mass index calculated and subjects classified as normal weight, overweight or obese. Physical activity levels, maximum inspiratory pressure (MIP) and inspiratory muscle endurance (IME) were also evaluated., Results: A total of 314 participants were included, separated into control group (181) and asthmatics (133), with a total mean age of 11 years. When both groups were compared, there were no significant differences in both MIP and IME. However, when groups were analyzed subdivided in children and adolescents, IME was significantly reduced (p = 0.003) in asthmatic adolescents. Indeed, when groups were also stratified considering the nutritional status, IME showed a reduction in asthmatic adolescents with overweight (p = 0.042) and obesity (p = 0.041) when compared to healthy controls. No effects of physical activity levels between groups were found., Conclusions: Results demonstrate a reduction in the IME in asthmatic adolescents with overweight and obesity, indicating an association between asthma, nutritional status and respiratory muscle function.

Background: Pulmonary changes that occur in cystic fibrosis may influence inspiratory muscle strength and endurance. We evaluated inspiratory muscle strength and endurance in children and adolescents with cystic fibrosis in comparison with healthy subjects., Methods: This is a cross-sectional observational study with subjects with cystic fibrosis and paired healthy individuals, age 6-18 y. Spirometry, impulse oscillometry, plethysmography, manovacuometry, and a protocol of inspiratory muscle endurance were performed., Results: Subjects with cystic fibrosis (n = 34) had higher maximum percent-of-predicted inspiratory pressure (PImax) than healthy (n = 68) subjects (118.5 ± 25.8% vs 105.8 ± 18.0%) and no significant difference in endurance (60.9 ± 13.3% vs 65.3 ± 12.3%). When restricting the analysis to subjects without Pseudomonas aeruginosa colonization and with FEV1 > 80%, PImax values were significantly higher, and inspiratory muscle endurance was lower, in comparison with the control group. PImax correlated significantly with FVC (r = 0.44, P = .02) and FEV1 (r = 0.41, P = .02), whereas endurance correlated better with total airway resistance (r = 0.35, P = .045) and with central airway resistance (r = 0.48, P = .004)., Conclusions: Children and adolescents with cystic fibrosis with no colonization by P. aeruginosa and normal lung function present increased inspiratory muscle strength and decreased endurance compared with healthy individuals, indicating that changes in the respiratory muscle function seem to be distinctly associated with pulmonary involvement. Strength was related to pulmonary function parameters, whereas endurance was associated with airway resistance., (Copyright © 2016 by Daedalus Enterprises.)

Objective: To determine the success rate of the manovacuometry test in children between 4 and 12 years of age., Methods: Cross-sectional study involving children and adolescents from 4 to 12 years of age, enrolled in three basic education schools. All subjects had the anthropometric and respiratory muscle strength (maximum inspiratory pressure and maximum expiratory pressure) data measured. Students whose parents did not authorize participation or who did not want to undergo the test were excluded. The test was considered successful when the subject reached acceptability (no air leaks) and reproducibility (variation <10% between the two major maneuvers) criteria established by guidelines. Failure was defined when subjects did not meet the above criteria. Data were expressed as mean and standard deviation and in absolute and relative frequency. The comparison between proportions was performed using the chi-square test., Results: We included 196 children and adolescents, mean age of 8.4±2.5 years, 53.1% female. The success rate of the manovacuometry test in children and adolescents evaluated was 92.3%. When comparing the differences between the success rates of preschool children with those children and adolescents of school age, there was a significantly lower success rate in the pre-school (85.1%) group compared to the school group (94.6%) (p=0.032). However, no significant differences (p=0.575) were found when gender comparisons were performed., Conclusions: The manovacuometry test showed a high success rate in both preschool and school population assessed. Furthermore, the rate of success appears to be related to aging., (Copyright © 2015 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.)

Aim: To generate reference values for respiratory muscle strength in healthy children aged three to twelve years., Methods: Participants were recruited from three schools and selected after a respiratory disease questionnaire analysis and written informed consent by parents or guardians. All participants included in the study had normal spirometry, height and weight were measured on the same day. Respiratory muscle strength was evaluated by a single examiner following the guidelines for pulmonary function tests. The association between MIP and MEP values with the potential predictive variables was analyzed using a multiple linear regression model., Results: A total of 171 participants were selected and distributed evenly by age. The age, height, weight and forced vital capacity showed moderate to strong correlations with both respiratory pressures. However, the regression model showed that height and weight were the best variables to predict MIP in both sexes, and age and weight to predict MEP. The power of prediction (R²) ranged from 46 to 58%. The intraclass correlation coefficient was used in a subgroup and demonstrated excellent reproducibility between tests., Conclusion: The results of this study demonstrate that the behavior of respiratory muscle strength in healthy preschool and school children can be explained by age, height and weight., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Unlabelled: The ventilatory mechanic changes that occur in cystic fibrosis (CF) patients may lead to alterations in the respiratory muscle strength levels. However, the findings regarding the strength profile in these patients are still contradictory., Objective: To evaluate, trough a literature review, the respiratory muscle strength behavior in CF patients. We have performed a search in Medline/Pubmed, Scielo, IBECS and LILACS databases selecting observational cross-sectional, prospective or retrospective studies, as well as randomized clinical trials, published between 1981 and 2011, using the following terms: cystic fibrosis, respiratory muscle strength, inspiratory maximal pressure and muscle training. The majority of the studies 71.24% have shown normal or above normal respiratory muscle strength, whilst 28.57% demonstrated reduced or near-normal values. Most of these findings were attributed to an increased work of breathing as a result of airway obstruction and chronic persistent cough. Taken together, the analyses of selected studies have showed conflicting findings regarding respiratory muscle strength behavior in these patients. However, most of the studies seem to indicate that CF patients presented maximum respiratory pressures normal or above predicted values.