Are Football Players More Prone to Muscle Injury after COVID-19 Infection? The "Italian Injury Study" during the Serie a Championship.

INTRODUCTION: Football was the first sport to resume competitions after the coronavirus disease 2019 (COVID-19) lockdown and promptly the hypothesis was raised of a potential relationship between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and musculoskeletal injuries in athletes. This study aimed to confirm the association between SARS-CoV-2 infection and muscle strain injury in a large population of elite football players and to investigate if the COVID-19 severity level could affect the risk of injury. METHODS: A retrospective cohort study involving 15 Italian professional male football teams was performed during the Italian Serie A 2020-2021 season. Injuries and SARS-CoV-2 positivity data were collected by team doctors through an online database. RESULTS: Of the 433 included players, we observed 173 SARS-CoV-2 infections and 332 indirect muscle strains. COVID-19 episodes mostly belonged to severity level I and II. The injury risk significantly increased after a COVID-19 event, by 36% (HR = 1.36, CI95% 1.05; 1.77, p-value = 0.02). The injury burden demonstrated an 86% increase (ratio = 1.86, CI95% 1.21; 2.86, p-value = 0.005) in the COVID-19 severity level II/III versus players without a previous SARS-CoV-2 infection, while level I (asymptomatic) patients showed a similar average burden (ratio = 0.92, CI95% 0.54; 1.58, p-value = 0.77). A significantly higher proportion of muscle-tendon junction injuries (40.6% vs. 27.1%, difference = 13.5%, CI95% 0.002%; 26.9%, p-value = 0.047) was found when comparing level II/III versus Non-COVID-19. CONCLUSIONS: This study confirms the correlation between SARS-CoV-2 infection and indirect muscle injuries and highlights how the severity of the infection would represent an additional risk factor.

Cardiovascular effects of COVID-19 lockdown in professional football players.

BACKGROUND: The COVID-19 pandemic with the stay-at-home orders and lockdown has dramatically forced athletes to stop team training and competitions, causing deep changes in habits and lifestyle. Aim of this study was to evaluate in a retrospective single center study the cardiovascular (CV) health and fitness of elite football player after COVID-19 lockdown in Italy and to compare such findings with the 2019 off-season period, in order to identify potential differences in the CV features and outcomes. METHODS: All 29 professional football players of the first male team were enrolled before resuming training and competition after COVID-19 lockdown and underwent several exams including physical examination, resting and stress electrocardiography (ECG), echocardiography, spirometry and blood tests. RESULTS: Median age was 27 years (23; 31), with no athlete being COVID-19 positive at the time of the evaluation. In comparison with the usual off-season 2-month detraining, significant differences were found for left ventricular (LV) mass (189 g [172; 212] vs. 181 g [167; 206], P=0.024) and LV Mass Index for body surface area (94 g/m2 [85; 104] vs. 88 g/m2 [79.5; 101.5], P=0.017), while LV mass/fat free mass remained unchanged (2.8 g/kg [2.6; 2.9] vs. 2.9 g/kg [2.6; 3.2], P=0.222). Respiratory function and metabolic profile were improved, while no significant changes were found in ECG findings, at rest and during exercise. CONCLUSIONS: Prolonged abstinence from training and competitions induced by lockdown elicited significant changes in comparison with off-season in parameters ascribable to detraining, as the changes in LV mass, in respiratory function and in metabolic profile.

Dynamic changes in left ventricular mass and in fat-free mass in top-level athletes during the competitive season.

BACKGROUND: Previous cross-sectional studies have demonstrated that fat-free mass (FFM) is an important determinant of left ventricular mass (LVM) in athletes. However, cross-sectional investigations have not the ability to detect the dynamic adaptation occurring with training. We hypothesized that LVM adapts concurrently with the increase of FFM induced by exercise conditioning. We sought to study the relationship between the variations of LVM and of FFM occurring in top-level soccer players during the season. METHODS: Twenty-three male top-level athletes were recruited. LVM was assessed by echocardiography and FFM by dual-energy X-ray absorptiometry. Serial measurements were performed pre-season, after 1 month, at mid- and end-season, and after 2 months of detraining. RESULTS: LVM significantly increased at mid-season versus pre-season values, reaching the highest value at the end of the season (p < 0.05). While body weight did not vary during the study period, FFM significantly increased (p < 0.05 for mid-/end-season vs. pre-season data). After the detraining, no significant differences were observed between pre-season and detraining echocardiographic data. The only independent predictors of LVM were left ventricular stroke volume and FFM (R = 0.36, p = 0.005; R = 0.35, p = 0.005, respectively). When ΔLVM index was set as dependent variable, the only independent predictor was ΔFFM (R = 0.87, p = 0.002). CONCLUSIONS: Changes in LVM occur in close association with changes in FFM, suggesting that the left ventricle adapts concurrently with the increase of the metabolically active tissue induced by training, i.e. the FFM. Therefore, the dynamic changes in FFM and LVM may reflect a physiological adaptation induced by intensive training.

Characterization of right atrial function and dimension in top-level athletes: a speckle tracking study.

Although many echocardiographic studies are available about the adaptation of left ventricle to intensive training, right heart function has been poorly investigated and no data are available about the right atrial (RA) function in top-level athletes. The aim of the study was to investigate RA function and dimension by standard echocardiography and 2D speckle tracking echocardiography (STE). One hundred top-levels athletes were recruited from professional sports team and were compared with 78 normal subjects. Athletes during an off-training period or during prolonged forced rest resulting from injuries were excluded. Top-level athletes had higher BSA as compared with controls and, as expected, a lower resting heart rate (p ≤ 0.001). RA area, volume, and volume index were significantly greater in athletes than in controls (p ≤ 0.001). This increase was associated with greater right ventricular and inferior vena cava diameters (p ≤ 0.001). Peak atrial longitudinal strain and peak atrial contraction strain values were significantly lower in athletes in comparison with controls (40.92 ± 9.86% vs. 48.00 ± 12.68%, p ≤ 0.001; 13.05 ± 4.84% vs. 15.99 ± 5.74%, p ≤ 0.001, respectively). Interestingly, while athletes presented a higher E/A ratio (p ≤ 0.001) and a lower peak A velocity (p ≤ 0.001), the E/e' ratio did not differ between the two groups. In top-level athletes the RA presents a physiological adaptation to intensive exercise conditioning which determines not only a morphological but also a functional remodeling. We reported for the first time reference values of RA strain in elite athletes, demonstrating that 2D STE is a useful tool to investigate RA longitudinal myocardial deformation dynamics in athlete's heart.

Supernormal diastolic function and role of left atrial myocardial deformation analysis by 2D speckle tracking echocardiography in elite soccer players.

PURPOSE: Top-level training is associated with morphological and functional changes in the heart. Left atrial (LA) enlargement can be regarded as a physiologic adaptation to exercise conditioning. Athletes show an improvement in myocardial diastolic properties and supernormal left ventricular (LV) diastolic function. The aims of the study were to assess diastolic function by pulsed Doppler tissue imaging (DTI) and to analyze the role of LA in athletes by speckle tracking echocardiography (STE). METHODS: Twenty-three male elite soccer players underwent a complete echocardiographic analysis. Twenty-six age-matched healthy sedentary men were used as controls. Measured variables included LA indexed volumes, DTI of the LV, peak atrial longitudinal strain, and peak atrial contraction strain (PACS). RESULTS: LA areas and indexed volumes were significantly higher in athletes (P < 0.001). Athletes had a higher peak E velocity (P < 0.001), a lower A peak (P < 0.01), and a higher peak E/A ratio (P < 0.0001); a higher Em peak (P < 0.001), a lower Am peak (P < 0.01), and a higher Em/Am ratio (P < 0.0001). Global PACS was lower in athletes compared with controls (P < 0.0001) and strongly correlated with mitral Am (r = 0.55; P < 0.0001), mitral Em (r =-0.41; P < 0.001), heart rate (r =-0.38; P < 0.01), and LA area (r = 0.18; P < 0.05). CONCLUSIONS: Athletes showed a shift in the pattern of ventricular filling period toward early diastole as seen through DTI analysis of the diastolic properties of LV and STE analysis of LA function. DTI is a useful tool to analyze the improved myocardial diastolic properties of athletes and STE may elucidate the role of LA in the context of athlete's heart remodeling.