The primary aim of this study was to determine the minimal clinically important difference (MCID) for the EuroQol-5D questionnaire (EQ-5D-5L) index and visual analogic scale (VAS) in individuals experiencing long-term post-COVID-19 symptoms. In addition, it was pretended to determine which variable discriminates better and to compare changes between individuals classified by the MCID. Design: Secondary analysis of a randomized controlled trial involving 42 individuals who underwent an 8-week intervention in a respiratory muscle training program. Results: A change of at least 0.262 and 7.5 for the EQ-5D-5L index and VAS represented the MCID, respectively. Only the EQ-5D-5L VAS showed acceptable discrimination between individuals who were classified as “improved” and those classified as “stable/not improved” (area under the curve = 0.78), although with a low Youden index (Youden index, 0.39; sensitivity, 46.2%; specificity, 93.1%). Those individuals who exceeded the established MCID for EQ-5D-5L VAS had significantly greater improvements in inspiratory muscle function, exercise tolerance, and peripheral muscle strength compared to participants classified as “stable/not improved”. Conclusions: Only the EQ-5D-5L VAS, especially when MCID was exceeded, showed an acceptable discriminative ability to evaluate the efficacy of an intervention in individuals with long-term post-COVID-19 symptoms.

Background: There is clinical interest in determining the effects of low-load blood flow restriction (LL-BFR) resistance training on muscle strength and hypertrophy compared with traditional high- and low-load (HL and LL) resistance training in healthy older adults and the influence of LL-BFR training cuff-pressure on these outcomes. Methods: A search was performed on the MEDLINE, PEDro, CINHAL, Web of Science, Science Direct, Scopus, and CENTRAL databases. Results: The analysis included 14 studies. HL resistance training produces a small increase in muscle strength (eight studies; SMD, −0.23 [−0.41; −0.05]) but not in muscle hypertrophy (six studies; (SMD, 0.08 [−0.22; 0.38]) when compared with LL-BFR resistance training. Compared with traditional LL resistance training, LL-BFR resistance training produces small–moderate increases in muscle strength (seven studies; SMD, 0.44 [0.28; 0.60]) and hypertrophy (two studies; SMD, 0.51 [0.06; 0.96]). There were greater improvements in muscle strength when higher cuff pressures were applied versus traditional LL resistance training but not versus HL resistance training. Conclusions: LL-BFR resistance training results in lower muscle strength gains than HL resistance training and greater than traditional LL resistance training in healthy adults older than 60 years. LL-BFR resistance training promotes a similar muscle hypertrophy to HL resistance training but is greater than that of traditional LL resistance training. Applying cuff pressures above the limb occlusion pressure could enhance the increases in muscle strength compared with traditional LL resistance training.

Objective: To establish the minimal clinically important difference (MCID) for inspiratory muscle strength (MIP) and endurance (IME) in individuals with long-term post-COVID-19 symptoms, as well as to ascertain which of the variables has a greater discriminatory capacity and to compare changes between individuals classified by the MCID. Design: Secondary analysis of randomised controlled trial of data from 42 individuals who performed an 8-week intervention of respiratory muscle training programme. Results: A change of at least 18 cmH₂O and 22.1% of that predicted for MIP and 328.5s for IME represented the MCID. All variables showed acceptable discrimination between individuals who classified as “improved” and those classified as “stable/not improved” (area under the curve ≥0.73). MIP was the variable with the best discriminative ability when expressed as a percentage of prediction (Youden index, 0.67; sensitivity, 76.9%; specificity, 89.7%). Participants classified as “improved” had significantly greater improvements in quality of life and lung function compared with the participants classified as “stable/not improved”. Conclusion: In individuals with long-term post-COVID-19 symptoms, the inspiratory muscle function variables had an acceptable discriminative ability to assess the efficacy of a respiratory muscle training programme. MIP was the variable with the best discriminative ability, showing better overall performance when expressed as a percentage of prediction.

Inspiratory and expiratory muscle training (RMT) has been shown to have beneficial effects in individuals with long-term post-COVID-19 symptoms. To assess the effects of adding RMT to an aerobic exercise (AE) training program for health-related quality of life (HRQoL) and exercise tolerance in individuals with long-term post-COVID-19 symptoms, and to evaluate the effects on physical and lung function, and psychological status. 64 individuals with long-term post-COVID-19 symptoms of fatigue and dyspnoea were randomly assigned to AE+RMT or AE+RMT_sham groups for an 8-wk intervention (AE: 50min/day, 2 times/wk; RMT: 40min/day, 3 times/wk). Primary outcomes were HRQoL (EuroQol-5D questionnaire) and exercise tolerance (cardiopulmonary exercise test). Secondary outcomes were physical function: respiratory muscle function (inspiratory/expiratory muscle strength and inspiratory muscle endurance), lower and upper limb strength (1-min Sit-to-Stand and handgrip force); lung function: spirometry testing and lung diffusing capacity; and psychological status (anxiety/depressive levels). Postintervention, there were no statistically significant improvements in HRQoL or exercise tolerance in the AE+RMT compared with the AE+RMT_sham group. In the AE+RMT group, large improvements in respiratory muscle function (d = 0.7 to 1.3) and low-moderate improvements in peak expiratory flow (d = 0.4) occurred compared with the AE+RMT_sham group. Lung function outcomes, lower and upper limb strength and psychological status did not increase more in the AE+RMT group than in the AE+RMT_sham group. For individuals with long-term post-COVID-19 symptoms, combining RMT with an AE training program resulted in improvements in respiratory muscle strength, inspiratory muscle endurance and peak expiratory flow; however, the differences between groups were not statistically significant for HRQoL, exercise tolerance, psychological distress, and lung diffusing capacity. United States Clinical Trials Registry (NCT05597774).

Objectives: The aim of this meta-analysis was to determine the effects of respiratory muscle training (RMT) on functional ability, pain-related outcomes, and respiratory function in individuals with sub-acute and chronic low back pain (LBP). Methods: The study selection was as follows: (participants) adult individuals with >4 weeks of LBP; (intervention) RMT; (comparison) any comparison RMT (inspiratory or expiratory or mixed) versus control; (outcomes) postural control, lumbar disability, pain-related outcomes, pain-related fear-avoidance beliefs, respiratory muscle function, and pulmonary function; and (study design) randomized controlled trials. Results: 11 studies were included in the meta-analysis showing that RMT produces a statistically significant increase in postural control (mean difference (MD) = 21.71 [12.22; 31.21]; decrease in lumbar disability (standardized mean difference (SMD) = 0.55 [0.001; 1.09]); decrease in lumbar pain intensity (SMD = 0.77 [0.15; 1.38]; increase in expiratory muscle strength (MD = 8.05 [5.34; 10.76]); and increase in forced vital capacity (FVC) (MD = 0.30 [0.03; 0.58]) compared with a control group. However, RMT does not produce an increase in inspiratory muscle strength (MD = 18.36 [−1.61; 38.34]) and in forced expiratory volume at the first second (FEV1) (MD = 0.36 [−0.02; 0.75]; and in the FEV1/FVC ratio (MD = 1.55 [−5.87; 8.96]) compared with the control group. Conclusions: RMT could improve expiratory muscle strength and FVC, with a moderate quality of evidence, whereas a low quality of evidence suggests that RMT could improve postural control, lumbar disability, and pain intensity in individuals with sub-acute and chronic LBP. However, more studies of high methodological quality are needed to strengthen the results of this meta-analysis.