Strength and endurance of the respiratory and handgrip muscles after the use of flunisolide in normal subjects

Maximal respiratory pressures: Measurements at functional residual capacity in individuals with different health conditions using a digital manometer

BACKGROUND

Measuring maximal respiratory pressure is a widely used method of investigating the strength of inspiratory and expiratory muscles.

OBJECTIVES

To compare inspiratory pressures obtained at functional residual capacity (FRC) with measures at residual volume (RV), and expiratory pressures obtained at FRC with measures at total lung capacity (TLC) in individuals with different health conditions: post-COVID-19, COPD, idiopathic pulmonary fibrosis (IPF), heart failure (CHF), and stroke; and to compare the mean differences between measurements at FRC and RV/TLC among the groups.

METHODS

Inspiratory and expiratory pressures were obtained randomly at different lung volumes. Mixed factorial analysis of covariance with repeated measures was used to compare measurements at different lung volumes within and among groups.

RESULTS

Seventy-five individuals were included in the final analyses (15 individuals with each health condition). Maximal inspiratory pressures at FRC were lower than RV [mean difference (95% CI): 11.3 (5.8, 16.8); 8.4 (2.3, 14.5); 11.1 (5.5, 16.7); 12.8 (7.1, 18.4); 8.0 (2.6, 13.4) for COVID-19, COPD, IPF, CHF, and stroke, respectively] and maximal expiratory pressures at FRC were lower than TLC [mean difference (95% CI): 51.9 (37.4, 55.5); 60.9 (44.2, 77.7); 62.9 (48.1, 77.8); 58.0 (43.9, 73.8); 57.2 (42.9, 71.6) for COVID-19, COPD, IPF, CHF, and stroke, respectively]. All mean differences were similar among groups.

CONCLUSION

Although inspiratory and expiratory pressures at FRC were lower than measures obtained at RV/TLC for the five groups of health conditions, the mean differences between measurements at different lung volumes were similar among groups, which raises the discussion about the influence of the viscoelastic properties of the lungs on maximal respiratory pressure.

Glucocorticoids and physical performance: A systematic review with meta-analysis of randomized controlled trials

Introduction

This systematic review with meta-analysis investigates the effect of glucocorticoids on maximal and submaximal performance in healthy subjects.

Methods

We searched for randomised controlled trials investigating the effect of glucocorticoids on physical performance in Web of Science, Scopus, Medline, Embase and SportDiscus in March 2021. Risk of bias was assessed with the revised Cochrane Collaboration Risk of Bias Tool (RoB2). Data from random effect models are presented as standardized difference in mean (SDM) with 95% confidence interval. We included 15 studies comprising 175 subjects.

Results

Two studies had high risk of bias. Glucocorticoids had a small positive effect on maximal physical performance compared to placebo (SDM 0.300, 95% CI 0.080 to 0.520) and the SDM for the 13 included comparisons was not heterogeneous (I2= 35%, p = 0.099). Meta regression found no difference in the effect of acute treatment vs. prolonged treatment or oral ingestion vs. inhalation (p > 0.124). In stratified analysis prolonged treatment (SDM 0.428, 95% CI 0.148 to 0.709) and oral ingestion (SDM 0.361, 95% CI 0.124 to 0.598) improved physical performance. Glucocorticoids improved aerobic performance (SDM 0.371, 95% CI 0.173 to 0.569) but not anaerobic performance (p = 0.135). Glucocorticoids did not change energy expenditure during submaximal performance (SDM 0.0.225 95% CI -0.771 to 0.112).

Discussion

This study indicates that glucocorticoids improves maximal performance and aerobic performance. Glucocorticoids did not affect the energy expenditure during submaximal performance. The conclusions are based on relatively few subjects leading to limited statistical power and uncertain estimates. Still, these results are consistent and should be of interest to WADA and anyone concerned about fair play.

Systematic Review Registration

Open Science Framework 2021-04-29 (https://osf.io/fc29t/).

New method for evaluating maximal respiratory pressures: Concurrent validity, test-retest, and inter-rater reliability

BACKGROUND

Maximal respiratory pressures (MRP) obtained at functional residual capacity (FRC) may reflect the real respiratory muscle pressure.

OBJECTIVES

To evaluate concurrent validity, test-retest, and inter-rater reliability of MRP performed with a new instrument in healthy individuals, and to compare values obtained at different volumes in healthy individuals and individuals with COPD.

METHODS

MRP of 100 healthy individuals were obtained using the TrueForce and the MicroRPM® at residual volume (RV) and total lung capacity (TLC) to evaluate concurrent validity. MRP were obtained at FRC using the TrueForce to evaluate reliability. Comparisons of inspiratory pressure values (FRC compared to RV) and expiratory pressure values (FRC compared to TLC) were performed with 100 healthy individuals and 15 individuals with COPD.

RESULTS

The intraclass correlation coefficient (ICC) was 0.77 and 0.86 for concurrent validity for inspiratory and expiratory pressures, respectively. Test-retest reliability showed an ICC of 0.87 for inspiratory pressure, and 0.78 for expiratory pressure; inter-rater reliability showed an ICC of 0.91 for inspiratory pressure, and 0.84 for expiratory pressure. Measurements performed at RV and TLC were higher when compared to FRC [mean difference (95%CI)= -8.30 (-11.82, -4.78) cmH2O; -37.29 (-42.63, -31.96) cmH2O] in healthy individuals, and -11.09 (-15.83, -6.35) cmH2O; -57.14 (-71.05, -43.05) cmH2O in COPD, for inspiratory and expiratory pressures, respectively.

CONCLUSION

MRP performed with the TrueForce presented good concurrent validity, good test-retest reliability, excellent inter-rater reliability for inspiratory pressure and good inter-rater reliability for expiratory pressure. MRP were lower when obtained at FRC for healthy individuals and with COPD.

Classification of postural profiles among mouth-breathing children by learning vector quantization

BACKGROUND

Mouth breathing is a chronic syndrome that may bring about postural changes. Finding characteristic patterns of changes occurring in the complex musculoskeletal system of mouth-breathing children has been a challenge. Learning vector quantization (LVQ) is an artificial neural network model that can be applied for this purpose.

OBJECTIVES

The aim of the present study was to apply LVQ to determine the characteristic postural profiles shown by mouth-breathing children, in order to further understand abnormal posture among mouth breathers.

METHODS

Postural training data on 52 children (30 mouth breathers and 22 nose breathers) and postural validation data on 32 children (22 mouth breathers and 10 nose breathers) were used. The performance of LVQ and other classification models was compared in relation to self-organizing maps, back-propagation applied to multilayer perceptrons, Bayesian networks, naive Bayes, J48 decision trees, k, and k-nearest-neighbor classifiers. Classifier accuracy was assessed by means of leave-one-out cross-validation, area under ROC curve (AUC), and inter-rater agreement (Kappa statistics).

RESULTS

By using the LVQ model, five postural profiles for mouth-breathing children could be determined. LVQ showed satisfactory results for mouth-breathing and nose-breathing classification: sensitivity and specificity rates of 0.90 and 0.95, respectively, when using the training dataset, and 0.95 and 0.90, respectively, when using the validation dataset.

CONCLUSIONS

The five postural profiles for mouth-breathing children suggested by LVQ were incorporated into application software for classifying the severity of mouth breathers' abnormal posture.