The COVID-19 pandemic has resulted in significant morbidity and mortality around the world. The spectrum of COVID-19 is broad, from clinical disease requiring intensive medical care to less severe symptoms that are treated with supportive care. The majority of COVID-19 cases fall into the mild-to-moderate category, with symptoms lasting less than 6 weeks. Nevertheless, the morbidity from COVID-19 is significant and can affect multiple body systems, most frequently the cardiac, pulmonary, hematologic, musculoskeletal, and gastrointestinal systems. For patients who wish to return to exercise after mild-tomoderate COVID-19, the wide range of disease expression presents a challenge for clinicians seeking to offer counsel. This literature review on return to activity following mild to moderate COVID-19 in the recreational athlete includes evidence-based considerations and recommendations for clinicians in guiding the safest return to activity.

Background: Coronavirus disease 2019 (COVID-19) affects multiple organ systems. Whether and how COVID-19 affects the musculoskeletal system remains unknown. We aim to assess the association between COVID-19 and risk of injury. Hypothesis: Runners who report having COVID-19 also report a higher incidence of injury. Study Design: Cross-sectional study. Level of Evidence: Level 4. Methods: An electronic survey was distributed from July through September 2020, by New York Road Runners, ASICS North America, race medical directors, and through social media. Inclusion criteria were runners 18 years or older who had participated in ≥1 race (running or triathlon) in 2019. Results: A total of 1947 runners participated and met inclusion criteria. Average age was 45.0 (SD, 12.2) years and 56.5% were women. A total of 123 (6.3%) runners self-reported having COVID-19; 100 (81%) reported their diagnosis was from a laboratory test (polymerase chain reaction or antibody) and 23 reported being diagnosed by a medical professional without confirmatory laboratory testing. Since March 2020, 427 (21.9%) reported an injury that prevented running for at least 1 week, including 38 of 123 (30.9%) who self-reported having COVID-19 and 389 of 1435 (21.3%) who did not report having COVID-19 ( P = 0.01). After adjusting for age, sex, the number of races in 2019, and running patterns before March 2020, runners who self-reported a diagnosis of COVID-19 had a higher incidence of injury compared with those who did not (odds ratio, 1.66; 95% CI, 1.11-2.48; P = 0.01). Conclusion: Injuries were more often self-reported by runners with laboratory-confirmed or clinically diagnosed COVID-19 compared with those who did not report COVID-19. Given the limitations of the study, any direct role of COVID-19 in the pathophysiology of injuries among runners remains unclear. Clinical Relevance: Direct and indirect musculoskeletal sequelae of COVID-19 should be further investigated, including the risk of exercise- and sports-related injury after COVID-19.

Techniques to visualize quantitative discrete event simulation input and output data are presented. General concepts connected with graphical excellence are discussed in a simulation context. Brief examples of graphs and visualizations are presented from a classic model of African port operations.

ObjectivesTo survey runners and triathletes about their willingness to resume in-person racing during the COVID-19 pandemic, health concerns related to mass races and changes in running patterns since the start of the pandemic.DesignAn electronic survey was distributed from 15 July to 1 September 2020 to runners and triathletes by New York Road Runners, ASICS North America, and race medical directors, and through social media.ParticipantsRunners and triathletes 18 years of age or older who participated in at least one race in 2019.ResultsA total of 2278 surveys were received. Not all participants answered every question; the denominator represents the number of responses to each question. Most participants were from the USA (1620/1940, 83.5%), of which over half were from New York (812/1475, 55.1%). Regarding when respondents would feel comfortable returning to in-person racing, the most frequent response was ‘Whenever local laws allow, but only if there are sufficient precautions’ (954/2173, 43.9%), followed by ‘Not until there is a vaccine’ (540/2173, 24.9%). The most common concerns about in-person races were crowded starting corrals (1802/2084, 86.5%), the number of COVID-19 cases in the race location (1585/2084, 76.1%) and the number of participants (1517/2084, 72.8%). Comparing running patterns before the pandemic to Summer 2020, the mean weekly mileage decreased from 25.5 (SD 15.4) miles to 22.7 (16.2) miles (p<0.001).ConclusionMost runners are willing to return to racing when local laws allow, though as of Summer 2020, many desired certain precautions to feel comfortable.