Impact of the COVID-19 pandemic on exercise tolerance and patient outcomes with Phase III cardiac rehabilitation in Japan: A multicenter study.

This study aimed to determine how behavioural restrictions due to the emergency declaration following the coronavirus disease 2019 (COVID-19) pandemic affect exercise tolerance and its outcomes in patients in Phase III cardiac rehabilitation programme. This is a multicenter retrospective cohort study. Participants in outpatient cardiac rehabilitation programmes and cardiopulmonary exercise testing before and after the emergency declarations were included. A total of 90 participants were included (median age 75.0 years, 69% male), and the changes in physical function and exercise tolerance were compared before and after the emergency declaration. Patients were divided into a decline-in-peak oxygen uptake (VO2 ) group and a nondecline-in-peak VO2 group. Comparison before and after the emergency declaration showed that the anaerobic threshold declined significantly and peak VO2 exhibited a downward trend. The decline-in-peak VO2 group consisted of 16 patients (17%) with better exercise tolerance, multiple comorbidities, and declined lower extremity muscle strength. These patients also had a higher rate of subsequent composite events (hazard ratio, 5.2; 95% confidence interval, 1.4-18.8, p = 0.01). Before and after the emergency declaration, the patient's exercise tolerance may decline, leading to a poor prognosis. This study suggests the importance of maintaining exercise tolerance during the COVID-19 pandemic.

Effects of cloth face masks on physical and cognitive performance during maximal exercise testing.

Wearing a cloth face mask has been shown to impair exercise performance; it is essential to understand the impact wearing a cloth face mask may have on cognitive performance. Participants completed two maximal cardiopulmonary exercise tests on a cycle ergometer (with and without a cloth face mask) with a concurrent cognitive task. Blood pressure, heart rate, oxygen saturation, perceived exertion, shortness of breath, accuracy, and reaction time were measured at rest, during each exercise stage, and following a 4-minute recovery period. The final sample included 35 adults (age = 26.1 ± 5.8 years; 12 female/23 male). Wearing a cloth face mask was associated with significant decreases in exercise duration (-2:00 ± 3:40 min, P = 0.003), peak measures of maximal oxygen uptake (-818.9 ± 473.3 mL/min, -19.0 ± 48 mL·min-1·kg-1, P < 0.001), respiratory exchange ratio (-0.04 ± 0.08, P = 0.005), minute ventilation (-36.9 ± 18 L/min), oxygen pulse (-3.9 ± 2.3, P < 0.001), heart rate (-7.9 ± 12.6 bpm, P < 0.001), oxygen saturation (-1.5 ± 2.8%, P = 0.004), and blood lactate (-1.7 ± 2.5 mmol/L, P < 0.001). While wearing a cloth face mask significantly impaired exercise performance during maximal exercise testing, cognitive performance was unaffected in this selected group of young, active adults.

[Assessment of the effect of the COVID-19 health crisis on the aerobic capacities of healthy patients]. / Mesure de l'effet de la crise sanitaire COVID-19 sur les capacités aérobies de patients sains.

OBJECTIVES: To measure the impact of the health crisis related to SARS-CoV-2 on the aerobic capacities of healthy patients based on the measurement of VO2 max and VO2 at the first ventilatory threshold (AT). To measure the impact of the introduction of the antibacterial filter on the ventilatory parameter measuring device. MATERIALS AND METHODS: Based on a multicentre (Angers and Cholet), observational and retrospective study, we want to analyze the effect of containment measures and the cessation of sports competitions on the measurement of VO2 max in healthy patients. For each patient, will be collected : the gross value of the max VO2 and indexed to the weight of the patient, as well as its percentage with respect to the expected theoretical value, the value of the VO2 at the aerobic threshold indexed to the wieght of the patient and the usual cardiorespiratory parameters (HR max, RR max, VE max, RER max). Two samples will be analyzed : patients with only one EFX ("unpaired" sample) and patients with multiple successive EFX over three years ("matched" sample). The impact of the antibacterial filter, used in one of the Sports Medicine departments, will be studied as a secondary issue. Statistical analyses were performed with the IBM SPSS 26 software. For all statistical tests, a p value of 0.05 was used in bilateral testing as the significance criterion. RESULTS: There is a significant difference in the value of VO2 max and AT in both the "unpaired" (VO2 max : 36.72 vs 35.08 mL/kg/min, p = 0.014 - AT : 21.03 vs 19.25 mL/kg/min, p < 0.001) and "matched" groups (VO2 max : 2.76 vs 2.64 L/min, p = 0.037 - AT : 1.55 vs 1.38 L/min, p = 0.001), more pronounced in patients over 60 years of age. The impact of the antibacterial filter does not show any particular impact within the "independent" sample. Within the "matched" sample, the significant age difference is not conclusive, but the exclusion of patients over the age of 60 makes the results meaningless.

Tolerance to physical activity and its changes in children after COVID-19 (literature review, own data)

Purpose - to summarize data from the literature and own experience regarding the course of COVID-19 in children;to determine changes in tolerance to physical activity in children who have experienced COVID-19. The issue of long-term consequences of the transferred COVID-19 is increasingly being raise in connection with the pandemic of COVID-19. The problem of changes in the functional state of the body health and improving the quality of life of children who have infected COVID-19 is relevant. To analyze these parameters, it is advisable to use the assessment of tolerance to physical activity Tolerance to physical activity is a total indicator of the body's physiological capabilities, which allows you to assess the processes of oxygen consumption by the myocardium and myocardial reserves, which are important in the overall adaptation of the body. The «gold standard» of assessing tolerance to physical activity is the determination of the maximum VO2, and other indicators, the control of which in dynamics will allow the development of medical and rehabilitation measures aimed at the elimination of post-COVID symptoms. © 2022 by the Author(s).

COVID-19 and athletes: Endurance sport and activity resilience study-CAESAR study.

Background: The COVID-19 pandemic and imposed restrictions influenced athletic societies, although current knowledge about mild COVID-19 consequences on cardiopulmonary and physiologic parameters remains inconclusive. This study aimed to assess the impact of mild COVID-19 inflection on cardiopulmonary exercise test (CPET) performance among endurance athletes (EA) with varied fitness level. Materials and Methods: 49 EA (nmale = 43, nfemale = 6, mean age = 39.94 ± 7.80 yr, height = 178.45 cm, weight = 76.62 kg; BMI = 24.03 kgm-2) underwent double treadmill or cycle ergometer CPET and body analysis (BA) pre- and post-mild COVID-19 infection. Mild infection was defined as: (1) without hospitalization and (2) without prolonged health complications lasting for >14 days. Speed, power, heart rate (HR), oxygen uptake (VO2), pulmonary ventilation, blood lactate concentration (at the anaerobic threshold (AT)), respiratory compensation point (RCP), and maximum exertion were measured before and after COVID-19 infection. Pearson's and Spearman's r correlation coefficients and Student t-test were applied to assess relationship between physiologic or exercise variables and time. Results: The anthropometric measurements did not differ significantly before and after COVID-19. There was a significant reduction in VO2 at the AT and RCP (both p < 0.001). Pre-COVID-19 VO2 was 34.97 ± 6.43 ml kg·min-1, 43.88 ± 7.31 ml kg·min-1 and 47.81 ± 7.81 ml kg·min-1 respectively for AT, RCP and maximal and post-COVID-19 VO2 was 32.35 ± 5.93 ml kg·min-1, 40.49 ± 6.63 ml kg·min-1 and 44.97 ± 7.00 ml kg·min-1 respectively for AT, RCP and maximal. Differences of HR at AT (p < 0.001) and RCP (p < 0.001) was observed. The HR before infection was 145.08 ± 10.82 bpm for AT and 168.78 ± 9.01 bpm for RCP and HR after infection was 141.12 ± 9.99 bpm for AT and 165.14 ± 9.74 bpm for RCP. Time-adjusted measures showed significance for body fat (r = 0.46, p < 0.001), fat mass (r = 0.33, p = 0.020), cycling power at the AT (r = -0.29, p = 0.045), and HR at RCP (r = -0.30, p = 0.036). Conclusion: A mild COVID-19 infection resulted in a decrease in EA's CPET performance. The most significant changes were observed for VO2 and HR. Medical Professionals and Training Specialists should be aware of the consequences of a mild COVID-19 infection in order to recommend optimal therapeutic methods and properly adjust the intensity of training.

Effect of BNT162b2 mRNA booster vaccination on VO2 max in recreational athletes: A prospective cohort study.

Background and Aims: The goal of the present study was to systematically evaluate the effect of a booster vaccination with the BNT162b2 messenger RNA (mRNA; Pfizer-BioNTech®) vaccine on maximum oxygen uptake (VO2 max), potential signs of (peri)myocarditis, and sports participation. Methods: Recreational athletes who were scheduled to undergo booster vaccination were evaluated with transthoracic echocardiography, serum measurements of high-sensitivity C-reactive protein(hsCRP) and high-sensitivity troponin I, and a bicycle cardiopulmonary exercise test (CPET) with serum lactate evaluation before the booster vaccine administration. Seven days postvaccination the test battery was repeated. Additionally, the subjects were asked to fill in a questionnaire on side effects and a subjective evaluation of their relative training volume and intensity as compared to the weeks before vaccination. Results: A group of 42 analysed athletes showed a statistically significant 2.7% decrease in VO2 max after vaccination (mean standard error of mean pre: 48.6 (1.4) ml/kg/min; post: 47.3 (1.4) ml/kg/min; p = 0.004). A potentially clinically relevant decrease of 8.6% or more occurred in 8 (19%) athletes. Other CPET parameters and lactate curves were comparable. We found no serological or echocardiographic evidence of (peri)myocarditis. A slight but significant increase in hsCRP was noted 1 week after vaccination. Side effects were mild and sports participation was generally unchanged or mildly decreased after vaccination. Conclusion: In our population of recreational endurance athletes, booster vaccination with the BNT162b2 mRNA vaccine resulted in a statistically significant decrease in VO2max 7 days after vaccination. The clinical impact hereof needs to be further determined. No major adverse events were observed.

Impact of wearing a FFP2 mask on cardiopulmonary fitness in school-aged children

Background and Aim: Wearing face masks to detain the COVID 19 pandemic in schools has become an integral part of fighting the virus. The most effective mask is the FFP2 mask. There is a lot of public concern, especially regarding wearing a face mask at school and especially during school sports. It is therefore important to determine whether wearing a FFP2-mask during physical activ-ity leads to changes measurable in cardiopulmonary exercise test-ing in children. Method(s): Cardiopulmonary exercise testing was performed two times by children aged 8-10 years as an incremental step test on a treadmill with and without a FFP2 within an interval of 2 weeks. A general questionnaire included medical history and sports par-ticipation since childhood. Result(s): We included 10 children (mean age 8.4 +/- 0.7 years, 6 males, 4 females). The mean parameters measured at peak exercise were comparable between both examinations (mean Peak VO2 = 39.3 +/- 3.4 vs 45.6 +/- 13.9 ml/min/kg;mean Peak HR 192/min +/- 9 vs 188/min +/- 12, mean O2pulse 6 +/- 1.4 ml/min vs. 7 +/- 1.8, mean VE 43.2 +/- 12.9 ml/min vs. 41.5 +/- 12.7 ml/min). Neither did the respiratory gases (O2 and CO2) measured 1 min into each step differ significantly (s. figure). This study is cur-rently ongoing. Conclusion(s): Since there were no significant differences with respect to peak parameters as well as with respect to the respiratory param-eters measured during each step, there is no indication to withhold physical activity even at peak capacity from children during a pan-demic which makes wearing face masks mandatory.

Impact of lockdown on cardiopulmonary function in children with heart disease

Background and Aim: The COVID-19 lockdown in Germany has led to the closure of sports facilities and to the closure of schools with their curricular physical activities (PA). However, physical activity is essential for improving or at least maintaining cardiopulmonary function assessed by VO2peak. VO2peak represents the best pre-dictor for mortality and morbidity in patients with congenital heart disease (CHD). It is therefore essential to evaluate the effect of lock-downs on this important parameter in children with heart disease. Method(s): We evaluated data from cardiopulmonary exercise data from before lockdown with twin-paired data from during lockdown. The statistically approved twin-pairing was achieved by matching patients with similar heart disease, age, sex, and test method. The subjects con-sisted of a variety of patients who had received cardiopulmonary exer-cise testing in our department in the past 3 years. Result(s): We were able to twin-pair 52 tests leading to 27 twins. A mean RER of more than 1.1 was achieved in both groups with comparable exercise times. There was a significant decrease of cardiopulmonary function (VO2peak: 35.7 +/- 9.8 vs.30.4 +/- 10.6) in our patient cohort along with a significant decrease in peak O2pulse (13.3 +/- 4.1 vs. 11.4 +/- 4.5), a surrogate parameter for stroke volume and most pronounced in peak minute ventilation (VE: 83.05 +/- 29.08 vs.71,49 +/- 24.96). Conclusion(s): We observed a significant decline of V O-2peak during lockdown. This involved a loss of cardiac function assessed by O2pulse as well as a loss of pulmonary function assessed by V E. We believe that the decline of these important predictive param-eters could be explained by the limited access to sports facilities as well as the restriction of regular daily movement as a consequence of closing schools and thus curricular PA. Measures need to be established to ensure access to physical activity for children suffer-ing from heart disease during lockdowns.

An Exercise Prescription as a Novel Management Strategy for Treatment of Long COVID.

Mechanisms causing the post-acute sequelae of SARS-CoV-2 (long COVID) remain elusive, but the clinical phenotype is consistent with cardiac deconditioning. We report a case series of patients with long COVID whose symptoms improved/resolved with exercise and present exercise training as a novel therapeutic strategy for management of long COVID syndrome. (Level of Difficulty: Intermediate.).

Cardiopulmonary Exercise Testing in Patients with Post-COVID-19 Syndrome.

BACKGROUND AND AIM: Several reports have shown the persistence of long term symptoms after the initial COVID-19 infection (post-COVID-19 syndrome). The objective of this study was to analyze the characteristics of cardiopulmonary exercise testing (CPET) performed in patients with a history of COVID-19, comparing subjects according to the presence of post-COVID-19 syndrome. METHODS: A cross-sectional study was performed. Consecutive patients >18 years with history of SARS-CoV-2 infection confirmed by polymerase chain reaction test and a CPET performed between 45 and 120 days after the viral episode were included. The association between variables related to CPET and post-COVID-19 syndrome was assessed using univariate and multivariate analysis. RESULTS: A total of 200 patients (mean age 48.8±14.3 years, 51% men) were included. Patients with post-COVID-19 syndrome showed significantly lower main peak VO2 (25.8±8.1mL/min/kg vs. 28.8±9.6mL/min/kg, p=0.017) as compared to asymptomatic subjects. Moreover, patients with post-COVID-19 syndrome developed symptoms more frequently during CPET (52.7% vs. 13.7%, p<0.001) and were less likely to reach the anaerobic threshold (50.9% vs. 72.7%, p=0.002) when compared to asymptomatic subjects. These findings were not modified when adjusting for confounders. CONCLUSION: Our data suggest that post-COVID-19 syndrome was associated with less peak VO2, a lower probability of achieving the anaerobic threshold and a higher probability of presenting symptoms during the CPET. Future studies are needed to determine if these abnormalities during CPET would have prognostic value.

Persistent dyspnea after COVID-19 is not related to cardiopulmonary impairment; a cross-sectional study of persistently dyspneic COVID-19, non-dyspneic COVID-19 and controls.

Background: Up to 53% of individuals who had mild COVID-19 experience symptoms for >3-month following infection (Long-CoV). Dyspnea is reported in 60% of Long-CoV cases and may be secondary to impaired exercise capacity (VO2peak) as a result of pulmonary, pulmonary vascular, or cardiac insult. This study examined whether cardiopulmonary mechanisms could explain exertional dyspnea in Long-CoV. Methods: A cross-sectional study of participants with Long-CoV (n = 28, age 40 ± 11 years, 214 ± 85 days post-infection) and age- sex- and body mass index-matched COVID-19 naïve controls (Con, n = 24, age 41 ± 12 years) and participants fully recovered from COVID-19 (ns-CoV, n = 14, age 37 ± 9 years, 198 ± 89 days post-infection) was conducted. Participants self-reported symptoms and baseline dyspnea (modified Medical Research Council, mMRC, dyspnea grade), then underwent a comprehensive pulmonary function test, cardiopulmonary exercise test, exercise pulmonary diffusing capacity measurement, and rest and exercise echocardiography. Results: VO2peak, pulmonary function and cardiac/pulmonary vascular parameters were not impaired in Long- or ns-CoV compared to normative values (VO2peak: 106 ± 25 and 107 ± 25%predicted, respectively) and cardiopulmonary responses to exercise were otherwise normal. When Long-CoV were stratified by clinical dyspnea severity (mMRC = 0 vs mMRC≥1), there were no between-group differences in VO2peak. During submaximal exercise, dyspnea and ventilation were increased in the mMRC≥1 group, despite normal operating lung volumes, arterial saturation, diffusing capacity and indicators of pulmonary vascular pressures. Interpretation: Persistent dyspnea after COVID-19 was not associated with overt cardiopulmonary impairment or exercise intolerance. Interventions focusing on dyspnea management may be appropriate for Long-CoV patients who report dyspnea without cardiopulmonary impairment.

Obese patients with long COVID-19 display abnormal hyperventilatory response and impaired gas exchange at peak exercise.

Aim: To analyze the impact of obesity on cardiopulmonary response to exercise in people with chronic post-COVID-19 syndrome. Patients & methods: Consecutive subjects with chronic post-COVID syndrome 6 months after nonsevere acute infection were included. All patients received a complete clinical evaluation, lung function tests and cardiopulmonary exercise testing. A total of 51 consecutive patients diagnosed with chronic post-COVID-19 were enrolled in this study. Results: More than half of patients with chronic post-COVID-19 had a significant alteration in aerobic exercise capacity (VO2peak) 6 months after hospital discharge. Obese long-COVID-19 patients also displayed a marked reduction of oxygen pulse (O2pulse). Conclusion: Obese patients were more prone to have pathological pulmonary limitation and pulmonary gas exchange impairment to exercise compared with nonobese COVID-19 patients.

In this study, the cardiopulmonary response to exercise in people with chronic post-COVID-19 syndrome was analyzed. More than half of patients diagnosed with chronic post-COVID-19 had reduced exercise capacity 6 months after hospital discharge. In addition, patients with chronic post-COVID-19 syndrome who were overweight or obese displayed exaggerated hyperventilation along with an impairment of oxygenation at peak exercise.

Effect of an Active Video Game Intervention Combined With Multicomponent Exercise for Cardiorespiratory Fitness in Children With Overweight and Obesity: Randomized Controlled Trial.

BACKGROUND: Childhood overweight and obesity have become major global health problems and are negatively related with the cardiorespiratory fitness (CRF) level in school children and adolescents. Exercise, specifically multicomponent training, is effective for CRF improvement, but the main challenge is to ensure adherence to exercise in children with overweight and obesity. Therefore, new ways of exercising that are more attractive and motivational for this population are needed and playing or training with active video games (AVGs) has been proposed as an effective alternative because they require full-body movement and therefore increase energy expenditure. OBJECTIVE: The main aim of this study was to investigate the effects of an AVG intervention combined with multicomponent training on CRF at maximal and submaximal intensities in children with overweight or obesity. METHODS: We recruited 28 children (13 girls and 15 boys) aged 9 to 11 years with overweight or obesity from medical centers and divided them into 2 groups, an intervention group (n=20) that participated in a 5-month supervised AVG exercise program combined with multicomponent exercise, and a control group (n=8) that continued daily activities without modification. A maximal stress test to measure CRF using a walking-graded protocol with respiratory gas exchange was performed by the participants. RESULTS: The AVG group showed a significant decrease in heart rate and oxygen uptake for the same intensities in the submaximal stages of the maximal treadmill test, as well as a lower oxygen uptake percentage according to the individual maximal oxygen uptake, whereas the control group did not show overall changes. No change in the peak oxygen uptake (VO2peak) was found. CONCLUSIONS: A 5-month AVG intervention combined with multicomponent exercise had positive effects on CRF at submaximal intensity, showing a lower heart rate and oxygen uptake at the same intensities and displaying a lower oxygen uptake percentage according to the individual (VO2peak). Greater benefits were found in children with the highest fat percentage. TRIAL REGISTRATION: ClinicalTrials.gov NCT04418713; https://clinicaltrials.gov/show/NCT04418713.

From the Lab to Real Life: Monitoring Cardiorespiratory Fitness during the COVID-19 Pandemic through Wearable Devices. An Exploratory Longitudinal Study on Healthy Participants.

COVID-19 containment measures hampered population cardiorespiratory fitness (which can be quantified as peak oxygen consumption (V.O2peak)) and the possibility to assess it using laboratory-based techniques. Although it is useful to ascertain the V.O2peak recovery after lockdowns, the community and most scientific institutions were unable to evaluate it. Wearable devices may provide the opportunity to estimate cardiorespiratory fitness outside of the laboratory, without breaking self-isolation; herein, we explore the feasibility of this approach. Fifteen healthy participants were tested every 2 weeks for 10 weeks during a reduction of containment measures after a strict lockdown. Physical activity levels were measured using the International Physical Activity Questionnaire-Short Form (IPAQ-SF). V.O2peak was estimated through a previously validated test based on the speed of a 60 m sprint run, the baseline-to-peak heart rate (HR) variation, and the velocity of HR decay after the sprint, and measured through a wearable HR monitor. Participants increased physical activity from the end of lockdown (1833 [917-2594] MET-min/week; median [1st quartile-3rd quartile]) until the end of follow-up (2730 [1325-3380] MET-min/week). The estimated V.O2peak increased by 0.24 ± 0.19 mL/(min*kg*week) (regression coefficient ± standard error). Based on previous knowledge on the impact of inactivity on V.O2peak, our study indicates that a 10-week period of reducing the stringency of containment measures may not be sufficient to counteract the detrimental effects of the preceding lockdown.

Aging, VO2 max, entropy, and COVID-19.

The decline in human performance with age at 5000 m, an athletic event requiring high VO2 max, is remarkably precise, and unavoidable, and related to entropy, even at an individual level. Women and men show an identical age-related decline, up to ~100 years old. The precision of the decline shows the limitations for therapy of aging. Mortality incidence for COVID-19 shows a similar relationship. We propose that initial VO2 max has a critical role in COVID sensitivity because of the direct relationship of disease severity with oxygen use, and the parallel decline in aging.

Deconditioning in COVID-19 survivors with reduced exercise performance: A role for endothelial dysfunction?

Recent studies have reported an impaired exercise response at cardiopulmonary exercise testing (CPET) during convalescence from coronavirus disease 2019 (COVID-19). In detail, these previous reports suggest the presence of functional limitations in a consistent proportion of COVID-19 survivors, in the absence of relevant alterations of ventilatory and gas exchange parameters at CPET. Therefore, deconditioning has been proposed as the main mechanism of the reduced peak oxygen uptake in this clinical setting. This interpretation of the results is supported by the evidence that deconditioning is a recognized aspect of the post-intensive care syndrome, with acute sarcopenia being frequently observed among COVID-19 survivors. Here, we hypothesized the role of endothelial dysfunction as a key pathogenic mechanism of the functional limitations of COVID-19, including multisystem deconditioning and subsequent exercise intolerance.

Consequence of acute lack of exercise: detraining and overall decrease in functional capacity

Almost everyone will experience a short-term lack of physical activity during their lifetime. In athletes who train regularly, the rea-son is most often an acute illness or injury. In the untrained population, restrictions on physical activity at any age are most often linked to health problems, but may also be related to anti-pandemic measures, as we have recently seen in the global fight against the COVID-19 pandemic. As "detraining" we mean a condition that occurs with such an extraordinary reducing of physical activity. It is manifested mainly by a decrease or loss of adaptive abilities, achieved by previous training or previous normal daily physical activity. In athletes there is a decrease in performance, in average fit people there is a weakening of the state of health, which requi-res convalescence. For people who have previously suffered from health problems, "detraining" can lead to loss of independence and deepening of their frailty to complete dependence on the environment. In the prevention of these negative consequences, it is necessary to reduce the period of restriction of movement to a minimum, ensure sufficient protein in the diet, minimize time spent in bed or sedentary and use online instruction on how to exercise at home. Otherwise, only a few weeks without optimal movement leads to a very significant reduction in physical condition, manifested in particular by a very significant decrease of adaptations earned from training especialy of cardiorespiratory capacity. © 2021, Czech Medical Association J.E. Purkyne. All rights reserved.

New COVID protocol for elite athletes to returning to sport

The COVID-Sars19 virus was a big problem in sports too. Before the Olympics, lots of Athletes lost motivation and the infected athletes lost some time from the preparation or missed the last qualification chance. The most important question how can we reduce the recovery time after the infection what is safety, without any cardiac risk. In our research, we create one new protocol that can reduce this time and the athletes don't lose too much time and don't lose their performance. © 2021 IEEE.

The impact of COVID-19 lockdown on professional soccer players' body composition and physical fitness.

During the COVID-19 lockdown, professional soccer players ceased their regular team training sessions and were provided with exercise programs to follow independently. This investigation assessed the impact of a 7-week COVID-19 lockdown and home-based individual physical training on professional soccer players' body composition and physical fitness. The study consisted of nineteen division 1 elite soccer players (age 27.68 ± 5.99 years, height 178.47 ± 5.44 cm) and compared the anthropometric and physical fitness parameters obtained post-transition period to those obtained post-COVID-19 lockdown. The statistical analysis indicated that body fat percentage was significantly higher after the lockdown period [t(18) = -5.59, p < 0.01, d = 0.56]. Furthermore, VO2max [t(17) = -11.54, p < 0.01, d = 0.57] and running time [t(17) = 3.94, p < 0.01, d = 0.76] values were significantly higher after the COVID-19 lockdown than those obtained after the transition period. In addition, significantly higher level of performance was demonstrated on squat jump [t(18) = -4.10, p < 0.01, d = 0.30], countermovement jump [t(18) = -7.43, p < 0.01, d = 1.11] and sit and reach tests [t(19) = -5.33, p < 0.01, d = 0.32]. Concurrently, lower body strength was indicated to be significantly greater (p < 0.01) following the COVID-19 lockdown. The training protocol provided during the confinement, due to the COVID-19 outbreak, was effective in keeping physical fitness at a significantly higher level compared to the transition period. Coaches and trainers are encouraged to examine the effectiveness of this protocol, as it may help them develop effective periodization programs during the transition period. This protocol may aid in the development of effective periodization programs that require minimal equipment and can be followed in similar situations.

Angiotensin-Converting Enzyme 2 (SARS-CoV-2 receptor) expression in human skeletal muscle.

The study aimed to determine the levels of skeletal muscle angiotensin-converting enzyme 2 (ACE2, the SARS-CoV-2 receptor) protein expression in men and women and assess whether ACE2 expression in skeletal muscle is associated with cardiorespiratory fitness and adiposity. The level of ACE2 in vastus lateralis muscle biopsies collected in previous studies from 170 men (age: 19-65 years, weight: 56-137 kg, BMI: 23-44) and 69 women (age: 18-55 years, weight: 41-126 kg, BMI: 22-39) was analyzed in duplicate by western blot. VO2 max was determined by ergospirometry and body composition by DXA. ACE2 protein expression was 1.8-fold higher in women than men (p = 0.001, n = 239). This sex difference disappeared after accounting for the percentage of body fat (fat %), VO2 max per kg of legs lean mass (VO2 max-LLM) and age (p = 0.47). Multiple regression analysis showed that the fat % (ß = 0.47) is the main predictor of the variability in ACE2 protein expression in skeletal muscle, explaining 5.2% of the variance. VO2 max-LLM had also predictive value (ß = 0.09). There was a significant fat % by VO2 max-LLM interaction, such that for subjects with low fat %, VO2 max-LLM was positively associated with ACE2 expression while as fat % increased the slope of the positive association between VO2 max-LLM and ACE2 was reduced. In conclusion, women express higher amounts of ACE2 in their skeletal muscles than men. This sexual dimorphism is mainly explained by sex differences in fat % and cardiorespiratory fitness. The percentage of body fat is the main predictor of the variability in ACE2 protein expression in human skeletal muscle.