Bayesian analysis of home advantage in North American professional sports before and during COVID-19.

Home advantage in professional sports is a widely accepted phenomenon despite the lack of any controlled experiments at the professional level. The return to play of professional sports during the COVID-19 pandemic presents a unique opportunity to analyze the hypothesized effect of home advantage in neutral settings. While recent work has examined the effect of COVID-19 restrictions on home advantage in European football, comparatively few studies have examined the effect of restrictions in the North American professional sports leagues. In this work, we infer the effect of and changes in home advantage prior to and during COVID-19 in the professional North American leagues for hockey, basketball, baseball, and American football. We propose a Bayesian multi-level regression model that infers the effect of home advantage while accounting for relative team strengths. We also demonstrate that the Negative Binomial distribution is the most appropriate likelihood to use in modelling North American sports leagues as they are prone to overdispersion in their points scored. Our model gives strong evidence that home advantage was negatively impacted in the NHL and NBA during their strongly restricted COVID-19 playoffs, while the MLB and NFL showed little to no change during their weakly restricted COVID-19 seasons.

Symptom cluster is associated with prolonged return-to-play in symptomatic athletes with acute respiratory illness (including COVID-19): a cross-sectional study-AWARE study I.

BACKGROUND: There are no data relating symptoms of an acute respiratory illness (ARI) in general, and COVID-19 specifically, to return to play (RTP). OBJECTIVE: To determine if ARI symptoms are associated with more prolonged RTP, and if days to RTP and symptoms (number, type, duration and severity) differ in athletes with COVID-19 versus athletes with other ARI. DESIGN: Cross-sectional descriptive study. SETTING: Online survey. PARTICIPANTS: Athletes with confirmed/suspected COVID-19 (ARICOV) (n=45) and athletes with other ARI (ARIOTH) (n=39). METHODS: Participants recorded days to RTP and completed an online survey detailing ARI symptoms (number, type, severity and duration) in three categories: 'nose and throat', 'chest and neck' and 'whole body'. We report the association between symptoms and RTP (% chance over 40 days) and compare the days to RTP and symptoms (number, type, duration and severity) in ARICOV versus ARIOTH subgroups. RESULTS: The symptom cluster associated with more prolonged RTP (lower chance over 40 days; %) (univariate analysis) was 'excessive fatigue' (75%; p<0.0001), 'chills' (65%; p=0.004), 'fever' (64%; p=0.004), 'headache' (56%; p=0.006), 'altered/loss sense of smell' (51%; p=0.009), 'Chest pain/pressure' (48%; p=0.033), 'difficulty in breathing' (48%; p=0.022) and 'loss of appetite' (47%; p=0.022). 'Excessive fatigue' remained associated with prolonged RTP (p=0.0002) in a multiple model. Compared with ARIOTH, the ARICOV subgroup had more severe disease (greater number, more severe symptoms) and more days to RTP (p=0.0043). CONCLUSION: Symptom clusters may be used by sport and exercise physicians to assist decision making for RTP in athletes with ARI (including COVID-19).

[Return to sport after the COVID-19 pandemic. How to behave?] / Ripresa dell'attività sportiva in seguito a pandemia COVID-19. Come comportarsi?

Italy, and all the world, has recently faced the arduous battle against the spread of a new coronavirus: SARS-CoV-2. This unexpected pandemic dramatically upended all areas of life, leading to a profound change in priorities, both in the medical as well as the social-economic field; and sports is no exception. Not surprisingly, the COVID-19 pandemic also walloped the world of sports. Every aspect of sports has been affected, leading professional and amateur leagues to stop their activities, in order to limit the spread of the virus, a painful but mandatory choice. Even the most popular sports in the world had to deal with the massive global threat of SARS-CoV-2. The Italian Sports Medical Federation (FMSI) has recently drawn up a protocol to be implemented when teams will receive from the authorities the permission to return to competitive activities. The purpose of this paper is to deepen the FMSI indications and allow wider dissemination and understanding.