Impact of (long) COVID on athletes' performance: a prospective study in elite football players.

OBJECTIVES: To investigate possible persistent performance deficits after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in elite athletes. METHODS: A prospective cohort study in three Belgian professional male football teams was performed during the 2020 - 2021 season. Participants were submitted to strength, jump, and sprint tests and an aerobic performance test (the Yo-Yo Intermittent Recovery test (YYIR)). These tests were repeated at fixed time intervals throughout the season. Assessment of SARS-CoV-2 infection was performed by a polymerase chain reaction (PCR) test before each official game. RESULTS: Of the 84 included participants, 22 were infected with SARS-CoV-2 during follow-up. At the first testing after infection (52.0 ± 11.2 days after positive PCR testing) significantly higher percentages of maximal heart rate (%HRmax) were seen - within the isolated group of infected players- during (p = .006) and after the YYIR (2 min after, p = .013), compared to pre-infection data. This increase in %HRmax was resolved at the second YYIR testing after infection (127.6 ± 33.1 days after positive PCR testing). Additionally, when comparing the first test after infection in formerly infected to non-infected athletes, significantly higher %HRmax were found during (p < .001) and after the YYIR test (p < .001),No significant deficits were found for the jump, muscular strength or sprint tests.Aerobic performance seems compromised even weeks after infection. Simultaneously, anaerobic performance seemed to be spared. Because of the potential detrimental effects on the immune system, caution might be advised with high-intensity exposure until aerobic performance is restored.KEY MESSAGESElite football players' aerobic performance seems to be affected for weeks after they return to sports after a SARS-CoV-2 infection.Similarly, anaerobic performance tests showed no discernible changes between both before and after SARS-CoV-2 infections.Regular YYIR testing is recommended to monitor aerobic performance after SARS-CoV-2 infection.

The Impact of COVID-19 on Male Semiprofessional Cricket Player's Mental Health and Performance Following the Resumption of Sporting Events.

The ability of a cricket player to manage their mental health helps them to perform optimally. This study investigated how mental health is related to performance of male cricket players during the resumption of sporting events after coronavirus disease 2019 (COVID-19) restrictions. Mental health profiles were established using the Depression, Anxiety, Stress Scale-21 (DASS-21), Athlete Burnout Questionnaire (ABQ), and Satisfaction with Life Scale (SWLS) instruments among male semiprofessional cricket players (n = 63). Performance metrics included: body fat percentage (BF%), range of motion (ROM), push-abdominal test, crazy catch test, t-test, 40-m sprint, and Cooper's test. Inferential statistics included Spearman's correlations with a significance level set at α < .05. Spearman's correlation reported a statistically significant relationship for SWLS and body mass index (BMI) (r = -0.263; p = .037) as well as between stress and abdominal test (r = 0.355; p = .004); crazy catch test (r = 0.249; p = .049); Cooper's test (r = 0.335; p = .009), VO2max (r = 0.308; p = .014), stress and abdominal test (r = -0.313; p = .012); as well as anxiety and 40-m sprint (r = 0.488; p = .027). This study provides an important snapshot of how symptoms of mental health are associated with performance. Further research should investigate the relationship between mental health and performance parameters among male players at varied skill levels.

Impact of COVID-19 infection on sports performance of elite university athletes.

BACKGROUND: Cardiopulmonary functions of athletes can be affected by the Coronavirus disease 2019 (COVID-19). This study aimed to investigate athletes' pattern of returning to sports after COVID-19, their experience of COVID-19-associated symptoms, and the disturbance in sports performance caused by the symptoms. METHODS: Elite university athletes who were infected with COVID-19 in 2022 were recruited for the survey and the data for 226 respondents were analyzed. Information about COVID-19 infection and the degree of disturbance in ordinary training and competition was collected. Their returning pattern to sports, the prevalence of COVID-19 symptoms, the degree of disturbance in sports by related symptoms, and factors associated with disturbance in sports and fatigue were analyzed. RESULTS: Results showed that 53.5% of the analyzed athletes returned to ordinary training immediately after quarantine, while 61.5% experienced disturbance in ordinary training, and 30.9% experienced that in competition. Most prevalent COVID-19 symptoms were lack of energy, easy fatiguability and cough. Disturbance in ordinary training and competition were mainly related to generalized, cardiologic, and respiratory symptoms. Women and those with severe and generalized symptoms had significantly higher odds of experiencing disturbance in training. Those with cognitive symptoms had higher odds of being "fatigue case." CONCLUSIONS: More than half of the athletes returned immediately to sports after the legal quarantine period of COVID-19 infection and experienced disturbance in ordinary training by related symptoms. Prevalent COVID-19 symptoms and the associated factors causing disturbance in sports and fatigue case were also revealed. This study will be helpful to establish the safe return guidelines essential for athletes after COVID-19.

Reduced athletic performance post-COVID-19 is associated with reduced anaerobic threshold.

Detailed characterisation of cardiopulmonary limitations in patients post-COVID-19 is currently limited, particularly in elite athletes. A male elite distance runner in his late 30s experienced chest pain following confirmed COVID-19. He underwent cardiopulmonary exercise testing (CPET) at 5 months postacute illness. Subjective exercise tolerance was reduced compared with normal, he described inability to 'kick' (rapidly accelerate). His CPET was compared with an identical protocol 15 months prior to COVID-19. While supranormal maximal oxygen uptake was maintained (155% of peak predicted V̇O2) anaerobic threshold (AT), a better predictor of endurance performance, reduced from 84% to 71% predicted peak V̇O2 maximum. Likewise, fat oxidation at AT reduced by 21%, from 0.35 to 0.28 g/min. Focusing exclusively on V̇O2 maximum risks missing an impairment of oxidative metabolism. Reduced AT suggests a peripheral disorder of aerobic metabolism. This finding may result from virally mediated mitochondrial dysfunction beyond normal 'deconditioning', associated with impaired fat oxidation.

Comparative Analysis of Soccer Performance Intensity of the Pre-Post-Lockdown COVID-19 in LaLiga™.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) forced a stoppage in the 2019/2020 season of LaLiga™, possibly influencing performance indicators in the return to competition. Therefore, here, we evaluated whether the stoppage due to the coronavirus 2019 disease (COVID-19) lockdown influenced physical performance compared to the start of LaLigaTM in terms of high-intensity efforts. Using a semi-automatic, multiple-camera system, running activities during 22 matches were analyzed. We compared the first 11 matches of the season (pre-lockdown) with the 11 matches just after the restart of LaLiga™ (post-lockdown). The results showed higher (p < 0.05) performance in the pre-lockdown period compared with the post-lockdown period, including in medium-speed running (14.1-21 km/h), high-speed running (21.1-24 km/h), and sprinting speed running distances (>24 km/h). However, the number of accelerations/min and decelerations/min were significantly higher during the post-lockdown period. Therefore, we conclude that the stoppage due to the COVID-19 lockdown generated lower physical performance in the post-lockdown period compared with the pre-lockdown period, most likely due to the accumulation of matches (congested schedules).

Swimming competitions in the era of COVID-19: Lessons from successfully hosting the International Swimming League.

Background: Organization of mass sport events in the COVID-19 era is utterly complicated. Containments measures, required to avoid a virus outbreak, force athletes to compete under circumstances they never experienced before, most likely having a deleterious effect on their performance. Purpose: We aimed to design a so-called athlete-friendly bubble system for the International Swimming League 2020 event, which is strict enough to avoid a COVID-19 outbreak, but still provides a supportive environment for the athletes. Methods: To avoid the feeling of imprisonment, athletes were permitted to spend a certain amount of time in the parks surrounding the hotels. Such alleviations were possible to apply with strict adherence to the hygienic and social distancing protocols and regular COVID-19 testing. Evaluation of every COVID-19 positive case was key, and if prolonged PCR positivity or false positive PCR result was identified, the unnecessary quarantine was planned to be lifted. Return to play protocol (RTP) was planned, in case of a COVID-19 infection of an athlete inside the bubble. To test, if the athlete-friendly system provided a supportive environment, we evaluated athlete performance. Results: 11,480 PCR tests were performed for 1,421 individuals. 63 COVID-19 positive cases were detected, of which 5 turned out to be clinically insignificant, either because of prolonged PCR positivity or because of a false positive result. 93.1% of the positive cases were detected in the local crew, while no athlete got infected inside the bubble, as the two infected athletes were tested positive upon arrival. RTP was provided for two athletes. 85% of the athletes showed improvement during the bubble and 8 world records were broken. Conclusion: The applied protocol proved to be effective, as no athlete got infected inside the bubble, moreover, the athlete-friendly system supported the athletes to improve their performance.

Effects of Capacitive-Resistive Electric Transfer on Sports Performance in Paralympic Swimmers: A Stopped Randomized Clinical Trial.

Throughout history a variety of therapeutic tools have been studied as possible enhancers of sports activities. This study proposes the use of Capacitive-Resistive Electric Transfer (CRET) as a performance booster to paralympic athletes, specifically those belonging to the Spanish Paralympic swimming committee. The study was a randomized, single-blind, and observer-blind, crossover clinical trial. Six athletes were randomly assigned to three groups: one treated with CRET (A); a placebo group (B) and a control group (C). The CRET group attended a twenty-minute session before being subjected to pool trials at distances of 50 and 100 m at maximum performance. Measurements were in two dimensions: time in seconds and the Borg scale for perceived exertion. Comparisons between groups were made with respect to distance and the main variables. In the case of perceived exertion, no significant changes were observed in any of the distances; however, in the case of the time variable, a significant difference was observed between Group A vs. Personal Record at 100 m distance (76.3 ± 6.8 vs. 68.4 ± 3.3). The proposed protocol and level of hyperthermia applied suggest refusal of CRET use for the 100-m distance a few minutes before sports practice. Our analysis suggests the need to modify the presented protocol. ClinicalTrials.gov identifier under NCT number: NCT04336007.

Training load, sports performance, physical and mental health during the COVID-19 pandemic: A prospective cohort of Swiss elite athletes.

BACKGROUND: The COVID-19 pandemic and associated restrictions have led to abrupt changes in the lives of elite athletes. OBJECTIVES: The objective of this prospective cohort study was to examine training load, subjective sports performance, physical and mental health among Swiss elite athletes during a 6-month follow-up period starting with the first Swiss lockdown. METHODS: Swiss elite athletes (n = 203) participated in a repeated online survey evaluating health, training, and performance related metrics. After the first assessment during the first lockdown between April and May 2020, there were monthly follow-ups over 6 months. RESULTS: Out of 203 athletes completing the first survey during the first lockdown, 73 athletes (36%) completed all assessments during the entire 6-month follow-up period. Sports performance and training load decreased during the first lockdown and increased again at the beginning of the second lockdown in October 2020, while symptoms of depression and financial fears showed only a transient increase during the first lockdown. Self-reported injuries and illnesses did not change significantly at any timepoint in the study. Stricter COVID-19 restrictions, as measured by the Government Stringency Index (GSI), were associated with reduced subjective sports performance, as well as lower training intensity, increased financial fears, poorer coping with restrictions, and more depressive symptoms, as measured by the 9-item module of the Patient Health Questionnaire-9 (PHQ-9). CONCLUSION: This study revealed a negative impact of the COVID-19 restrictions on sports performance, training load and mental health among Swiss elite athletes, while the rate of self-reported injuries and illnesses remained unaffected.

Impact of Sudden Rule Changes on Player Injuries and Performance: Insights from Australian Football.

This study investigated the effects of reduced quarter time due to COVID-19 pandemic rule changes, on running performance and injuries in Australian Football. Microsensor data for eight matches performed by the same 17 players were compared between the 2019 (standard) and 2020 (COVID-19) seasons using linear and generalised mixed models. Injury rates were assessed in 34 players across the full 2019 season, and 32 players across the full 2020 season. The total distance (ES = 1.28 [0.55 to 2.02]), high-speed (>18 km/h) (ES = 0.44 [-0.24 to 1.12]) and very highspeed (>24 km/h) (ES = 0.27 [-0.41 to 0.94]) distances, PlayerLoad™ (ES = 0.96 [0.25 to 1.67]), high-intensity efforts (ES = 0.48 [-0.20 to 1.16]), and accelerations (ES = 0.33 [-0.34 to 1.01]) were smaller (p ≤ 0.01) for the 2020 than the 2019 season. Expressed relative to playing time, distance (ES=-0.38 [-1.06 to 0.30]), PlayerLoad™ (ES = -0.27 [-0.94 to 0.41]), and acceleration efforts (ES = -0.50 [-1.18 to 0.18]) were greater (p < 0.05) for the 2020 than the 2019 season. No significant differences in maximum ball-in-play periods nor the difference between the 1^st and 4^th quarters were evident. Injury rates remained similar between 2019 (3.36 per game) and 2020 (3.55 per game). However, the proportion of injuries that led to lost time (missed games) was greater for the 2020 (38%) than 2019 season (24%). The changes in the rules had a profound impact on player performance and increased the likelihood of time loss injuries.

Two Years of COVID-19 Pandemic: How the Brazilian Serie A Championship Was Affected by Home Advantage, Performance and Disciplinary Aspects.

As a result of the COVID-19 pandemic, the Brazilian Serie A championship was played without crowds in 2020 and partially in the 2021 season. We verified if the home advantage (HA) was different between the 2018, 2019, 2020, and 2021 seasons. We also compared the HA, performance, and disciplinary aspects between the rounds with or without crowds and verified the association between the number of absent athletes because of health protocols and the HA in the 2020 and 2021 seasons. We calculated the HA using the Pollard method. The performance aspects were goals, corners, shots, and ball possession, and the disciplinary aspects were fouls, yellow cards, and red cards. The HA was higher in the 2018 season compared with the other seasons. The rounds with crowds showed higher HAs than the two previous seasons and the teams had more shots and scored more goals than in the rounds without crowds. There were 457 athletes in the 2020 season and 123 athletes in the 2021 season who were absent because of health protocols, and there was no association between absence and HA. The COVID-19 pandemic affected soccer in the two last seasons in different ways in the Brazilian Serie A championship.

Effects of Dryland Training During the COVID-19 Lockdown Period on Swimming Performance.

PURPOSE: To examine the effect of dryland training during an 11-week lockdown period due to COVID-19 on swimming performance. METHODS: Twelve competitive swimmers performed 50- and 300-m maximum-effort tests in their preferred stroke and 200-, 400-, and four 50-m front crawl sprints (4 × 50 m) before and after the lockdown period. Critical speed as an index of aerobic endurance was calculated using (1) 50-, 300-, and (2) 200-, 400-m tests. Blood lactate concentration was measured after the 400- and 4 × 50-m tests. To evaluate strength-related abilities, the dryland tests included handgrip and shoulder isometric strength. Tethered swimming force was measured during a 10-second sprint. During the lockdown period, dryland training was applied, and the session rating of perceived exertion training (sRPE) load was recorded daily. RESULTS: sRPE training load during the lockdown was decreased by 78% (16%), and critical speed was reduced 4.7% to 4.9% compared to prelockdown period (P < .05). Performance time in 200, 300, and 400 m deteriorated 2.6% to 3.9% (P < .05), while it remained unaltered in 4 × 50- and 50-m tests (P > .05). Tethered force increased 9% (10%) (P < .01), but handgrip and shoulder isometric force remained unaltered (P > .05). Blood lactate concentration decreased 19% (21%) after the 400-m test and was unchanged following the 4 × 50-m tests (P > .05). CONCLUSIONS: Performance deterioration in the 200, 300, and 400 m indicates reduced aerobic fitness and impaired technical ability, while strength and repeated-sprint ability were maintained. When a long abstention from swimming training is forced, dryland training may facilitate preservation in short-distance but not middle-distance swimming performance.

Effects of air pollution exposure on inflammatory and endurance performance in recreationally trained cyclists adapted to traffic-related air pollution.

The aim of the present study was to analyze the effects of traffic-related air pollution (TRAP) on markers of inflammatory, neuroplasticity, and endurance performance-related parameters in recreationally trained cyclists who were adapted to TRAP during a 50-km cycling time trial (50-km cycling TT). Ten male cyclists performed a 50-km cycling TT inside an environmental chamber located in downtown Sao Paulo (Brazil), under TRAP or filtered air conditions. Blood samples were obtained before and after the 50-km cycling TT to measure markers of inflammatory [interleukin-6 (IL-6), C-reactive protein (CRP), interleukin-10 (IL-10), intercellular adhesion molecule-1 (ICAM-1)] and neuroplasticity [brain-derived neurotrophic factor (BDNF)]. Rating of perceived exertion (RPE), heart rate (HR), and power output (PO) were measured throughout the 50-km cycling TT. There were no significant differences between experimental conditions for responses of IL-6, CRP, and IL-10 (P > 0.05). When compared with exercise-induced changes in filtered air condition, TRAP provoked greater exercise-induced increase in BDNF levels (TRAP = 3.3 ± 2.4-fold change; Filtered = 1.3 ± 0.5-fold change; P = 0.04) and lower exercise-induced increase in ICAM-1 (Filtered = 1.1 ± 0.1-fold change; TRAP = 1.0 ± 0.1-fold change; P = 0.01). The endurance performance-related parameters (RPE, HR, PO, and time to complete the 50-km cycling TT) were not different between TRAP and filtered air conditions (P > 0.05). These findings suggest that the potential negative impacts of exposure to pollution on inflammatory, neuroplasticity, and performance-related parameters do not occur in recreationally trained cyclists who are adapted to TRAP.

Human Movement Quality Assessment Using Sensor Technologies in Recreational and Professional Sports: A Scoping Review.

The use of sensor technology in sports facilitates the data-driven evaluation of human movement not only in terms of quantity but also in terms of quality. This scoping review presents an overview of sensor technologies and human movement quality assessments in ecologically-similar environments. We searched four online databases to identify 16 eligible articles with either recreational and/or professional athletes. A total of 50% of the studies used inertial sensor technology, 31% vision-based sensor technology. Most of the studies (69%) assessed human movement quality using either the comparison to an expert's performance, to an exercise definition or to the athletes' individual baseline performance. A total of 31% of the studies used expert-based labeling of the movements to label data. None of the included studies used a control group-based study design to investigate impact on training progress, injury prevention or behavior change. Although studies have used sensor technology for movement quality assessment, the transfer from the lab to the field in recreational and professional sports is still emerging. Hence, research would benefit from impact studies of technology-assisted training interventions including control groups as well as investigating features of human movement quality in addition to kinematic parameters.

The Influence of Gender and the Specificity of Sports Activities on the Performance of Body Balance for Students of the Faculty of Physical Education and Sports.

A sense of balance is required in sports activities, conditioning the quality of movements and physical performance. (1) The purpose of the study is to investigate the influence of gender and the specificity of sports activities on body balance. The investigated participants are 157 students of the Faculty of Physical Education and Sports/Bachelor's degree: 109 men (age = 20.49 ± 2.03, body mass index, BMI = 22.96 ± 3.20), and 48 women (age = 20.21 ± 1.51, BMI = 21.05 ± 2.78). (2) Design: Cross-sectional study, with the definition of the variables gender and sport activity with three stages (non-athletes/NA, team sports games/TSG, and individual sports/IS). The evaluation was based on four dynamic balance tests (Bass test/points, Functional reach test/cm, Fukuda test/degrees of rotation, and Walk and turn field sobriety test/errors) and three static balance tests (Flamingo test/falls, Stork test, and One-leg standing test with eyes closed/s). (3) Results: The variance analysis (multivariate and univariate tests) indicates the superiority of women in most tests applied, but with significantly better values (p < 0.05) only for the Flamingo test and Bass test. Men have superior results only for vestibular stability (Fukuda test) and One-leg standing test, but it is statistically insignificant (p > 0.05). The TSG group has slightly better values than the IS group for the whole set of tests conducted, but these are not statistically significant (p > 0.05), so we cannot highlight the certain superiority of TSG practitioners over those involved in IS. Both the TSG and the IS group outperformed all tests compared to the NA group, with significant differences (p < 0.05), especially for the TSG. Conclusion: Women have better values than men on most tests, and performance sports students have higher average scores than those in the NA group, which demonstrates the beneficial influence of specific training on static and dynamic postural stability.

Analysis of a double Poisson model for predicting football results in Euro 2020.

First developed in 1982, the double Poisson model, where goals scored by each team are assumed to be Poisson distributed with a mean depending on attacking and defensive strengths, remains a popular choice for predicting football scores, despite the multitude of newer methods that have been developed. This paper examines the pre-tournament predictions made using this model for the Euro 2020 football tournament. These predictions won the Royal Statistical Society's prediction competition, demonstrating that even this simple model can produce high-quality results. Moreover, the paper also presents a range of novel analytic results which exactly quantify the conditions for the existence and uniqueness of the solution to the equations for the model parameters. After deriving these results, it provides a novel examination of a potential problem with the model-the over-weighting of the results of weaker teams-and illustrates the effectiveness of ignoring results against the weakest opposition. It also compares the predictions with the actual results of Euro 2020, showing that they were extremely accurate in predicting the number of goals scored. Finally, it considers the choice of start date for the dataset, and illustrates that the choice made by the authors (which was to start the dataset just after the previous major international tournament) was close to optimal, at least in this case. The findings of this study give a better understanding of the mathematical behaviour of the double Poisson model and provide evidence for its effectiveness as a match prediction tool.

Aerobic capacity of professional soccer players before and after COVID-19 infection.

This investigation aimed to assess the aerobic capacity of professional soccer players pre-and post-COVID-19 infection. Twenty-one division-1 elite soccer players (age 24.24 ± 5.75 years, height 178.21 ± 5.44 cm, weight 74.12 ± 5.21 kg) participated in this study. This observational study compared the same players' aerobic capacity pre-, and 60-days post COVID-19 recovery. The statistical analysis demonstrated that the infected players had significantly lower VO2max values [t(20) = 5.17, p < 0.01, d = 0.613 (medium effect)], and significantly lower VO2 values at respiratory compensation point (RC) [t(20) = 2.97, p < 0.05, d = 0.39 (small effect)] after recovery. Furthermore, results indicated a significantly lower running time (RT) on the treadmill [t(20) = 4.84, p < 0.01, d = 0.46 (small effect)] when compared to the results that were obtained before they got infected. In addition, velocity at VO2max (VVO2max) was significantly lower [t(20) = 2.34, p < 0.05, d = 0.41 (small effect)] and the heart rate values at ventilatory threshold (VT) [t(20) = -2.79, p < 0.01, d = 0.55 (medium effect)] and RC [t(20) = -3.72, p < 0.01, d = 0.52 (medium effect)] were significantly higher post-recovery. The aforementioned findings indicate that post COVID-19 soccer players may not reach full recovery at two months. Therefore, our results highlight that further adaptations and improvements are needed with regard to aerobic capacity before soccer players return to professional games.

Tackle and ball carrier demands of rugby league: a seven-year league-wide study including over 1,000,000 tackle events.

OBJECTIVES: Describe the highest frequency and variability for tackle events in rugby league. Investigate seasonal differences in total tackle events per match over a seven-year period. DESIGN: Retrospective observational. METHODS: Tackle events (i.e., ball carrier events [attacker] and tackler involvements [defender]) from 864 male professional rugby league players competing in 1176 Super League matches from 2014 to 2020 were included. A series of linear mixed effect models were used to determine the frequency and variability during peak 1-, 3-, 5-, 10-, 20-, 40-min and whole-match tackle events per player per match at a positional group level. Differences between seasons for the total number of tackle events per match were compared using a one-way analysis of variance and with Tukey's honestly significant difference test. RESULTS: Tackle events were greatest for Props (51.5 [47.7-55.4] per match). Within-players, between-matches, and between-seasons variability was <10 % for tackle events. There were significantly less tackle events and tackler involvements per match in 2014 and a significantly more tackle events per match in season 2020b when compared with all other seasons. CONCLUSIONS: Large between-position variability in peak tackle events, ball carrier events, and tackler involvements would suggest that coaches should separate players into positional groups and prescribe training accordingly. Total number of tackle events, ball carrier events, and tackler involvements were significantly greater in season 2020b when compared to season 2014 to 2019 (inclusive) which may be a consequence of rule changes introduced to the sport.

Postlockdown Performance in French Swimming Championships.

PURPOSE: To measure the proportion of French swimmers that progressed, stagnated, or regressed during the 2020 national championship compared with previous ones. METHOD: Individual best performances were collected at the French national championships from 2000 to 2020. Yearly proportions of swimmers who improved, stagnated, or regressed in performances were compared with their previous performances. RESULTS: In 2020, the proportion of swimmers with performance regression has significantly increased (33% vs 17% in 2019). Women showed a higher proportion of performance regression (41%) than men (26%, P < .0001) in 2020. Only 39% of women and 53% of men experienced progression in 2020 (vs 60.8% [3.7%] and 66.7% [5.2%], respectively, in the previous years). Only the 2008 and 2009 championships showed a regression proportion that did not increase with age. The 2010 championship (the year of swimsuits ban) showed a higher proportion of regressing athletes than these previous years. Long-distance events showed higher proportion of performance regression (36.2% [0.5%]) for 400-, 800-, and 1500-m races than for short-distance ones (32.1% [3.2%]; 50-, 100-, and 200-m events). Breaststroke events showed higher regression (42.4%) than other styles (30.5% [2.1%]). Younger swimmers more often improved their performance than older ones (61.9% [8.5%] for swimmers less than 18 y of age vs 20.0% [10.8%] for those 25 y and older). CONCLUSION: A high proportion of swimmers experienced performance regression during the 2020 French national championships. A higher impact was observed among female, long-distance, and breaststroke swimmers. Eight weeks of lockdown without training may have led to poorer swimming performances.

COVID-19 disease in professional football players: symptoms and impact on pulmonary function and metabolic power during matches.

This study aimed at: (1) Reporting COVID-19 symptoms and duration in professional football players; (2) comparing players' pulmonary function before and after COVID-19; (3) comparing players' metabolic power (Pmet ) before and after COVID-19. Thirteen male players (Age: 23.9 ± 4.0 years, V̇O2peak : 49.7 ± 4.0 mL/kg/min) underwent a medical screening and performed a running incremental step test and a spirometry test after COVID-19. Spirometric data were compared with the ones collected at the beginning of the same season. Players' mean Pmet of the 10 matches played before COVID-19 was compared with mean Pmet of the 10 matches played after COVID-19. Players completed a questionnaire on COVID-19 symptoms and duration 6 months following the disease. COVID-19 positivity lasted on average 15 ± 5 days. "General fatigue" and "muscle fatigue" symptoms were reported by all players during COVID-19 and persisted for 77% (general fatigue) and 54% (muscle fatigue) of the players for 37 ± 28 and 38 ± 29 days after the disease, respectively. No significant changes in spirometric measurements were found after COVID-19, even though some impairments at the individual level were observed. Conversely, a linear mixed-effects model analysis showed a significant reduction of Pmet (-4.1 ± 3.5%) following COVID-19 (t = -2.686, p < 0.05). "General fatigue" and "muscle fatigue" symptoms may persist for several weeks following COVID-19 in professional football players and should be considered for a safer return to sport. Players' capacity to compete at high intensities might be compromised after COVID-19.