Pulmonary Rehabilitation Outcomes of Post-Acute COVID-19 Patients during Different Waves of the Pandemic.

(1) Background: Between the beginning of the coronavirus pandemic and summer 2022, we distinguished four pandemic waves, with different characteristics of the affected patients. This study investigated the impact of patient characteristics on the outcome of inpatient pulmonary rehabilitation (PR). (2) Methods: Using a prospective approach, the characteristics of post-acute COVID-19 patients of the different waves who participated in inpatient PR were compared based on their assessments and results collected as part of PR (Cumulative Illness Rating Scale (CIRS), six-minute walk test (6-MWT), Pulmonary Function Testing (PFT), and Functional Independent Measurement (FIM). (3) Results: A total of 483 patients were included in the analysis (Wave 1 n = 51, Wave 2 n = 202, Wave 3 n = 84, Wave 4 n = 146). Compared to Wave 3 + 4, patients of Wave 1 + 2 were older (69 vs. 63 years; p < 0.001), had a significantly lower CIRS (13.0 vs. 14.7 points; p = 0.004), had significant better PFT (FVC: 73 vs. 68%pred; p = 0.009; DLCOSB: 58 ± 18 vs. 50 ± 17%pred; p = 0.001), and showed significantly more comorbidities (2.0 vs. 1.6 n/pers.; p = 0.009). Wave 3 + 4 showed significantly greater improvements according to the 6-MWT (147 vs. 188 m; p < 0.001) and the FIM (5.6 vs. 21.1 points; p < 0.001). (4) Conclusions: Patients of the COVID-19 infection waves differed significantly according to their anthropometric data, incidence of comorbidities, and impact of the infection. All cohorts achieved clinically relevant and significant functional improvements during PR, with significant higher improvements in Wave 3 + 4.

Effects of Sprint Interval and Endurance Respiratory Muscle Training on Postcycling Inspiratory and Quadriceps Fatigue.

PURPOSE: We investigated whether a 4-wk period of respiratory muscle endurance training (RMET) or respiratory muscle sprint interval training (RMSIT) would lead to an attenuation of inspiratory muscle and quadriceps fatigue after a bout of high-intensity cycling compared with a placebo intervention (PLAT), as predicted by the respiratory metaboreflex model. METHODS: Thirty-three active, young healthy adults performed RMET, RMSIT, or PLAT. Changes in inspiratory muscle and quadriceps twitches in response to a cycling test at 90% of peak work capacity were assessed before and after training. EMG activity and deoxyhemoglobin (HHb, via near-infrared spectroscopy) of the quadriceps and inspiratory muscles were also monitored during the cycling test, along with cardiorespiratory and perceptual variables. RESULTS: At pretraining, cycling reduced the twitch force of the inspiratory muscles (86% ± 11% baseline) and quadriceps (66% ± 16% baseline). Training did not attenuate the drop in twitch force of the inspiratory muscles (PLAT, -3.5 ± 4.9 percent-points [p.p.]; RMET, 2.7 ± 11.3 p.p.; RMSIT, 4.1 ± 8.5 p.p.; group-training interaction, P = 0.394) or quadriceps (PLAT, 3.8 ± 18.6 p.p.; RMET, -2.6 ± 14.0 p.p.; RMSIT, 5.2 ± 9.8 p.p.; group-training interaction P = 0.432). EMG activity and HHb levels during cycling did not change after training for either group. Only RMSIT showed a within-group decrease in the perception of respiratory exertion with training. CONCLUSIONS: Four weeks of RMET or RMSIT did not attenuate the development of exercise-induced inspiratory or quadriceps fatigue. The ergogenic effects of respiratory muscle training during whole-body exercise might be related to an attenuation of perceptual responses.

Sex differences in quadriceps and inspiratory muscle fatigability following high-intensity cycling.

OBJECTIVES: As females have been hypothesized to have more fatigue resistant inspiratory muscles, this study aimed to compare the development of inspiratory and leg muscle fatigue between males and females following high-intensity cycling. DESIGN: Cross-sectional comparison. METHODS: 17 healthy young males (27 ±â€¯6 years, V̇O2peak 55 ±â€¯10 mlï½¥min-1ï½¥kg-1) and females (25 ±â€¯4 years, V̇O2peak 45 ±â€¯7 mlï½¥min-1ï½¥kg-1) cycled until exhaustion at 90% of the peak power output achieved during an incremental test. Changes in quadriceps and inspiratory muscle function were assessed via maximal voluntary contractions (MVC) and assessments of contractility via electrical stimulation of the femoral nerve and cervical magnetic stimulation of the phrenic nerves. RESULTS: Time to exhaustion was similar between sexes (p = 0.270, 95% CI -2.4 - 0.7 min). MVC of the quadriceps was lower after cycling for males (83.9 ±â€¯11.5% vs. 94.0 ±â€¯12.0% of baseline for females, p = 0.018). Reductions in twitch forces were not different between sexes for the quadriceps (p = 0.314, 95% CI -5.5 - 16.6 percent-points) or inspiratory muscles (p = 0.312, 95% CI -4.0 - 2.3 percent-points). Changes in inspiratory muscle twitches were unrelated to the different measures of quadriceps fatigue. CONCLUSION: Females incur similar peripheral fatigue in the quadriceps and inspiratory muscles compared with men following high-intensity cycling, despite smaller reduction in voluntary force. This small difference alone does not seem sufficient to warrant different training strategies to be recommended for women.

Effects of Sprint-Interval and Endurance Respiratory Muscle Training Regimens.

INTRODUCTION: Recently a novel, time-saving respiratory muscle sprint-interval training (RMSIT) was developed. To test the extent to which RMSIT improves respiratory muscle performance compared with a conventional respiratory muscle endurance training (RMET), a novel incremental respiratory muscle test (IncRMT), loading inspiratory and expiratory muscles, was designed to assess performance changes associated with respiratory muscle training (RMT). METHODS: Healthy, moderately trained males and females (age: 26 ± 5 yr, V˙O2peak: 47 ± 12 mL·min·kg) were randomized and balanced to three groups (RMSIT 5m/5f; RMET 6m/6f; PLAT 5m/6f). Lung function, respiratory muscle strength, and IncRMT performance were tested before and after 1 month of RMT. During the IncRMT, muscle activity and muscle deoxygenation were assessed via surface EMG and near-infrared spectroscopy of sternocleidomastoid (STERNO), intercostal (INTER), and abdominal (ABDO) muscles. RESULTS: Two-way ANOVA revealed a main effect of training for increased maximal voluntary ventilation (P = 0.001) and maximal inspiratory pressure (P = 0.017). Both RMT groups increased work of breathing during training sessions to the same extent (RMSIT: +17.4 ± 8.9 kJ; RMET: +26.2 ± 16.1 kJ; P = 0.143) with a larger increase in average mouth pressure in RMSIT (RMSIT: +20.0 ± 15.0 cm H2O; RMET: +3.3 ± 1.5 cm H2O; P = 0.001). After training, IncRMT duration increased in both RMT groups compared with PLAT (RMSIT: +5.6 ± 2.1 min, P = 0.0006 vs PLAT; RMET: +3.8 ± 4.2 min, P = 0.020 vs PLAT). At similar work, only INTER activity during inspiration increased after RMET. Higher performance after RMSIT was associated with higher activity in STERNO and ABDO, but after RMET, STERNO, INTER, and ABDO showed higher activity. CONCLUSION: One month of RMSIT and RMET shows similar improvements in respiratory muscle performance despite different duration of training sessions. Also, muscular adaptations might differ.