Case Report: Return to Sport Following the COVID-19 Lockdown and Its Impact on Injury Rates in the German Soccer League

Effect of COVID-19 on Injury Incidence and Severity in Professional Female Football Players: A Cohort Prospective Study

BACKGROUND

Earlier statements suggested a negative impact of coronavirus disease 2019 (COVID-19) infection on sports performance and injury risk. With the COVID-19 pandemic under control and the dominance of a less-severe strain of the virus, there is a need to confirm whether these adverse effects still apply to the current situation.

HYPOTHESIS

Infected players would have a higher noncontact muscle injury incidence compared with noninfected counterparts.

STUDY DESIGN

Cohort observational study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Seven teams (n = 147 players) competing in the Spanish professional women's football league (Liga F) were prospectively monitored during the 2021-2022 season. Data from noncontact injuries were recorded and classified following the latest consensus statement from the International Olympic Committee. COVID-19 was certified by the medical staff by regular polymerase chain reaction analysis.

RESULTS

Ninety-two players suffered at least 1 noncontact muscle injury during the season. Injury incidence during the season was similar in players with COVID-19 (n = 83) and players without infection (5.1 ± 6.7 versus 4.9 ± 10.0 injuries/1000 h of play, respectively; P = 0.90). Players with COVID-19 were not more likely to suffer noncontact injuries compared with those players without infection (R2 = 0.02; odds ratio [OR] 95% confidence interval [95% CI] = 0.36-1.38; P = 0.31). There was no effect of COVID-19 on the days of absence due to injury (R2 = 0.01; OR 95% CI = 1.00-1.01; P = 0.44) or in the classification of the severity of the injury (P = 0.79).

CONCLUSION

COVID-19 has no significant effect on noncontact injury incidence and severity in professional female football players.

CLINICAL RELEVANCE

Currently, COVID-19 infection does not alter noncontact muscle injury risk in professional football and requires no further attention in terms of injury management. Usual return-to-play protocols apply to COVID-19 considering the particularities of each player since the severity of infection, period of inactivity, and effects on the player's health and performance.

Epidemiology of Injury and Illness in North American Professional Men's Soccer: Comparing COVID-19 Lockdown With Previous Seasons

BACKGROUND

After COVID-19 lockdown, studies across Europe and Asia examined its effect on professional soccer injury rates and severity; however, COVID-19 lockdown influence on injuries in United States men's professional soccer has not been evaluated.

HYPOTHESIS

Injury and illness rates during the 2020 season were higher than the previous 2 seasons.

STUDY DESIGN

Retrospective observational cohort study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Medical staff from participating Major League Soccer (MLS) clubs entered injuries and athletic exposures during the study period into a league-wide electronic medical record system. Injury rate and severity were analyzed to examine differentials between the 2020 COVID season and historical controls.

RESULTS

The injury incidence rate per 1000 hours in 2020 was 10.8, ie, higher than 2018 (5.4) and 2019 (5.0) (P < 0.05). Training injury incidence rate increased in 2020 (8.9) compared with 2018 (2.5) and 2019 (2.6) (P < 0.05), whereas match injury incidence decreased in 2020 (18.3) compared with 2018 (24.0) and 2019 (22.7) (P < 0.05). Incidence rates of lower extremity muscle injuries (6.04), anterior cruciate ligament (ACL) injuries (0.17), and concussions (0.49) were also higher in 2020 compared with 2018 (2.5, 0.07, 0.27) and 2019 (2.36, 0.05, 0.22) (P < 0.05). More injured players in 2020 missed >90 days (17.7%) than in 2018 (10.2%) and 2019 (10.1%) (P < 0.05). Incidence of all non-COVID-19 illness was higher in 2020 (3.93) than 2018 (1.53) and 2019 (1.32) (P < 0.05).

CONCLUSIONS

During 2020, there were significant increases in incidence rates of overall injuries, training injuries, lower extremity muscular injuries, ACL injuries, concussions, and non-COVID illness, along with a higher percentage of players missing >90 days compared with the 2 previous seasons.

CLINICAL RELEVANCE

These results may help clarify the effects of future MLS inseason work stoppages and periods of restricted training.

Injury and Illness Trends in the National Hockey League Following an Abrupt Cessation of Play

Background

The National Hockey League (NHL) saw an unprecedented disruption to the competitive calendar due to the COVID-19 pandemic in March of 2020. Returning to play following an abrupt cessation of activity is a known risk factor for athletes.

Purpose

To analyze the occurrence and severity of events (injury and illness) in the NHL and to understand any differences in occurrence and severity between pre-pandemic seasons and seasons that immediately followed.

Study Design

Descriptive Epidemiology Study.

Methods

Using a retrospective cohort inclusive of all players on active rosters in the NHL between 2016-2023, public access injury and illness data were collected. Outcome measures included event incidence, period prevalence, and severity (mean days lost; MDL), as well as incidence rate ratio (IRR) comparing pre- and post-pandemic seasons.

Results

IRR for illness peaked in December 2021 (IRR = 62.46; 95% CI 13.65 to 285.91). Incidence of upper body injuries was significantly higher in 2020-21 (IRR = 1.70, p = 0.001) and 2021-22 (IRR = 1.40, p = 0.044) compared to pre-pandemic seasons (Incidence = 17.58 injuries / 1000 player-hours). Injury incidence increased as the 2022-23 season progressed (p = 0.004); injury incidence was stable across all other seasons. Mean days lost (MDL) to injury was higher in 2020-21 (MDL = 18.12, p < 0.001), 2021-22 (MDL = 18.46, p = 0.015), and 2022-23 (MDL = 18.12, p < 0.001) compared to pre-pandemic seasons (MDL = 17.34).

Conclusion

Incidence of upper body injuries increased in the 2020-21 and 2021-22 NHL regular seasons while it decreased significantly in the 2022-23 regular season compared with the four pre-pandemic seasons. This suggests a need to examine if modifiable risk factors exist for determining optimal return to play strategies following an abrupt cessation of play.

Level of Evidence

3.

Changes in injury type among NBA athletes in response to the COVID-19 pandemic

CONTEXT

The 2019-2020 NBA season was altered significantly by the COVID-19 pandemic with a midseason suspension of games, the NBA 'bubble' tournament, and a shortened offseason. Concerns were raised regarding player conditioning and the potential increased risk of injury due to the schedule changes. The purpose of this study was to determine the impact of the COVID-19 pandemic and associated schedule changes on NBA injuries. It was hypothesized that injury rates would be higher in the year following the pandemic and teams who participated in the bubble would have higher injury rates in the following season than non-bubble teams. Furthermore, the types of injuries would shift toward more severe injuries in the condensed 2019-20 season and the following 2020-21 season.

DESIGN

Retrospective Cohort Study.

METHODS

The NBA's public injury reports were queried to identify players listed on an injury report. Standardized injury events were calculated for four pre-COVID-19 seasons (2015-2019), the COVID-19 season (2019-2020), and the post-COVID-19 season (2020-2021). Injury characteristics including type and location were extracted for each year and differences within each period were calculated.

RESULTS

When excluding injury events related to COVID-19 health and safety protocols, the overall injury events per 1000 exposures were not significantly different between time periods of pre-COVID-19, COVID-19, and post-COVID-19 seasons; (p = 0.199), and no difference was found in the rates of teams who participated in the bubble. Injuries, including soreness and strains, significantly decreased while fracture injuries significantly increased in the COVID-19 year.

CONCLUSIONS

The COVID-19 pandemic led to an increased number of games missed, but no increase in injury rates when accounting for health and safety protocols. Additionally, bubble participation had no impact on injury rates. However, despite no changes in injury rates, the types of injuries changed with an increased proportion of severe injuries and decreased proportion of minor injuries.

Has Sustained Time Away From Sports Due to the COVID-19 Pandemic Led to Increased Sport-Related Soft Tissue Injuries?

BACKGROUND

A decrease in sport-related injuries was observed in 2020, which has been attributed to COVID-19 and recommendations to suspend organized sports. In adult populations, increased injury rates have been noted in athletes returning to play after an extended period of reduced play, attributable to deconditioning. There is growing literature surrounding concern over increased injury risk after return to sport after the COVID-19 shutdowns.

HYPOTHESIS

Like adults, pediatric patients experience an increase in sport-related injuries after periods of "deconditioning," such as during the COVID-19 shutdown.

STUDY DESIGN

Descriptive epidemiology study.

LEVEL OF EVIDENCE

Level 4.

METHODS

The Consumer Product Safety Commission's National Electronic Injury Surveillance System database was queried to identify 13- to 18-year-old patients who sustained a sprain/strain type injury in 2019 or 2021 to an extremity, and involved sporting equipment for basketball, baseball/softball, soccer, and football. The control group was established as patients who sustained injury in 2019, and the post-COVID-19 group was established as those in 2021. Quantity of injuries sustained in these 2 groups were compared and analyzed by subgroup.

RESULTS

There was a significant difference in the total number of sport-related sprains/strains in 2019 versus 2021 (P = 0.01), with more injuries in 2019 (n = 151,067) than in 2021 (n = 104,041). There were more injuries in boys than in girls. Proportion of injuries by sports were similar in both time periods. There was a significant decrease in basketball-related injuries by 21% (P ≤ 0.01, relative risk ratio [rrr] = 0.7979) and a significant increase in football-related injuries by 14% (P = 0.01, rrr = 1.1404) and in soccer injuries by 14.2% (P = 0.03, rrr = 1.1422).

CONCLUSION

There is significant heterogeneity in injury rates by sports, with no conclusive increase in injuries, contrary to expectations.

CLINICAL RELEVANCE

This study suggests that the relationship between deconditioning and injury may be less clear in the child-athlete, and gives recommendations for return to sport after extended breaks.

STRENGTH-OF-RECOMMENDATION TAXONOMY (SORT)

Level 2c.

The Surgical Management of NCAA Division 1 College Football Injuries Post COVID-19: A Single Institution Retrospective Review

ABSTRACT

Cohen, JL, Cade, WH, Harrah, TC, Costello II, JP, and Kaplan, LD. The surgical management of NCAA Division 1 college football injuries post COVID-19: A single institution retrospective review. J Strength Cond Res 38(5): 906-911, 2024-The unprecedented COVID-19 pandemic had a significant impact on college football operations, including athletes' training regimens. As a result of these changes, concern for increased injury susceptibility post COVID-19 regulations has become a point of discussion. The current study sought to evaluate the incidence of surgical injury among NCAA Division 1 college football players at the authors' institution during the first full season after start of the COVID-19 pandemic compared with previous years. Retrospective chart review was performed for all players who sustained injuries requiring surgery while a member of the NCAA Division 1 football program during the 2009-2021 seasons. A p -value of ≤0.05 was used to determine significance. A total of 23 surgical injuries occurred in 22 players during the 2021 season compared with 121 in 118 players in the 12 previous seasons combined ( p = 0.0178; RR = 1.47). There was a significant increase in shoulder injuries ( n = 13 vs. n = 31; p = <0.0001; RR = 3.05) and specifically a significant increase in labral tears ( n = 10 vs. n = 30; p = 0.0003; RR = 2.74). No difference was seen in knee injuries ( n = 10 vs. n = 77; p = 0.27; RR = 1.35) and specifically no difference in anterior cruciate ligament injuries ( n = 3 vs. n = 31; p = 0.77; RR = 1.17). This phenomenon is multifactorial in nature, but alterations to players' training and preparations because of the COVID-19 pandemic likely resulted in suboptimal conditioning, leading to the increased incidence of surgical injuries emphasizing the importance of adequate strength training and conditioning.

Bodily Practices and Meanings Articulated in the Physical Exercise of Older Adults in Santiago de Chile Post-COVID-19

This article presents the results of almost nine months of ethnographic research on the relationship between physical exercise and health in older people in the post-COVID-19 context. Via exploratory-descriptive qualitative research and the use of a convenient sample, I shed light on this relationship using the stories and life experiences of 40 older people (10 men and 30 women, including two women instructors for senior classes) who exercise regularly. The meanings they attributed to physical exercise during COVID-19 and after it are explained, emphasising first that there is no health in a context of not feeling safe; once there is a feeling of security, the most relevant meanings can be exposed in three directions. First, exercise produces a sense of identity linked to "being an athlete" and "belonging to a group". Second, exercising is valued as participating in something meaningful (the meanings range from self-realisation, independence, and autonomy to feelings of happiness). Finally, and linked to the sense of identity, those who train alone show more commitment and total hours spent in physical exercise and physical activity than those who train in groups. Even though older people are not a homogeneous group, they generally faced the pandemic as an ageist situation that affected their lives and how they saw sports and health. This article describes the strategies they used during COVID-19 related to exercise and well-being and those used once the pandemic restrictions were no longer present. The qualitative aspects that physical exercise brings to this population are highlighted. The research results give voice to older people, showing their heterogeneity and the meanings and practices that unite them. These inputs are rich material for studies on physical activity, older people, and well-being.

Assessing the COVID-19 pandemic's impact on pediatric baseball and basketball-related craniofacial and neck injuries treated in United States emergency departments, 2003-2022

BACKGROUND

A large proportion of United States (U.S.) youth play basketball, baseball, softball, or T-ball. Each of the activities poses a documented risk of craniofacial and neck injuries. However, few studies have assessed the national prevalence of pediatric craniofacial and neck injuries in this population, particularly following the COVID-19 pandemic.

METHODS

The National Electronic Injury Surveillance System (NEISS) dataset was used to identify pediatric craniofacial and neck injuries associated with basketball, baseball, softball, or T-ball from 2003-2022 in a cross-sectional study. The annual number of injuries before and after the onset of the COVID-19 pandemic with 95% confidence intervals were calculated. Interrupted time series analysis (ITSA) was used to estimate the pandemic's impact on the monthly number of injuries incurred nationally.

RESULTS

Both overall and stratified by sport involvement, the annual number and rate of injuries identified in NEISS decreased significantly after the COVID-19 pandemic. ITSA demonstrated that the monthly number of injuries decreased -4094.4 (95% CI = -5100, -3088.7) immediately after the beginning of the pandemic. The number of injuries began increasing towards pre-pandemic levels at a rate of 110.6 (95% CI = 64, 157.2) injuries per month after the initial plunge.

CONCLUSION

Prior to the-pandemic, there was a steady decline in craniofacial and neck injuries due to basketball, baseball, softball and T-ball among children, aged <18 years. The shutdown during the initial months of the COVID-19 pandemic resulted in a precipitous drop in such injuries. Current rates are approaching pre-pandemic levels and may exceed them. Continued efforts are needed to keep the pre-pandemic progress.

Supporting athletes during a challenging situation: recommendations from a global insight of COVID-19 home-based training experience

BACKGROUND

For athletes, overcoming obstacles in challenging situations like pandemic home training is crucial. Strategies and approaches in this context are not well-documented. Our study aims to investigate such a scenario from a performance standpoint, based on a major global crisis: the COVID-19 pandemic and lockdown.

METHODS

This cross-sectional study surveyed athletes without disabilities using online questionnaires (35 languages) from May to July 2020. Questions included aspects of alternative routines, training monitoring, recovery, sleep patterns, injury occurrence/prevention based on structured answers, and an open-ended question on lockdown training experiences.

RESULTS

Of the 11,762 athletes from 142 countries, 63% were male, including at World-Class, International, National, State and Recreational levels. During lockdown, 25% athletes used innovative or modern ways to maintain or improve fitness e.g., virtual reality and tracking devices (favoring World-Class level, 30%). Many athletes, regardless of gender (43%) watched video competitions to improve/maintain their mental skills and performance [World-Class (47%) and International (51%)]. Contact frequency between athletes and their coaches was mainly at least once a week (36%), more among higher-level (World-Class/International) than lower-level athletes (27 vs. 16%). Higher-level athletes (≥ 54%) monitored training load and were assisted by their coaches (21%). During lockdown, stretching (67%) was considered one of the primary means of recovery, especially for higher-level athletes (> 70%). Compared to pre-lockdown, about two-thirds of athletes reported "normal" or "improved" sleep quality and quantity, suggesting a low sleep quality pre-lockdown. On average, 40% utilized injury prevention exercises (at least) once a week [World-Class (51%) and International (39%)]. Most injury occurrences during lockdown involved the knee (18%), ankle (16%), and back (9%). Four key themes emerged regarding lockdown experiences: remote training adaptation (e.g., shifting training focus), training creativity (e.g., using household items), performance enhancement opportunities (e.g., refocusing neglected aspects), and mental and motivation challenges.

CONCLUSIONS

Both male and female athletes, particularly those of higher levels, displayed some adaptalibity during the COVID-19 lockdown, employing innovative approaches and technology for training. Many athletes implemented load monitoring, recovery, and attentive of injury prevention, while optimizing their sleep quality and quantity. Athletes demonstrated their abilities to navigate challenges, and utilized different coping strategies in response to the lockdown's constraints.

The Impact of the SARS-COVID-19 Lockdowns on the Subjectively Perceived Performance Level of Amateur Athletes after Returning to the Gyms

Since December 2019, few issues have garnered as much global attention as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-19). The imposed lockdowns in 2020/21, which led to the closure of all gyms, barred people from participating in their favourite sports activities. This study explores athletes' self-evaluations of their performance levels upon return to training facilities post-reopening. Data were collected in May 2021, after the end of the second lockdown, using a national online questionnaire. The study recorded 20 demographic and training-specific parameters to discern the factors influencing self-perceived performance upon resuming gym activities after the 2020/2021 lockdown. A total of 1378 respondents participated in the study. Of the total number of participants, 27.5% (365) reported regaining 100% of their original performance level after reopening their studios, a proportion that comprised 212 males, 150 females, and 3 individuals of unspecified gender. Additionally, 35.7% (474) estimated their performance level to be up to 75%, followed by 30% (398) recording their performance level at 50%, and a minority of 6.8% (90) determining their performance level to be up to 25%. Exercise intensity prior to lockdown, training experience, sex, and concurrent practice of another sport significantly influenced the athletes' self-assessment of their current fitness levels (p > 0.001, p > 0.001, p > 0.001, and 0.006, respectively). We need to understand the factors that shape self-perception, especially in case of another lockdown, in order to provide preventive assistance concerning mental and physical well-being. Positive influences on self-perception include prior athletic experience, intensive training before the lockdown, and continued participation in sports throughout the lockdown. Younger age is also favourable, but this may not necessarily reflect the benefits of youth; rather, it could indicate the current lack of accessible online sports activities for older individuals. Women, however, might have a less favourable perception of their own athletic performance.

Longitudinal analysis of the incidence rate of injury in elite youth football: Trends over six years including the COVID-19 pandemic period

OBJECTIVES

We aimed to analyze injury trends and the possible effects of the coronavirus disease (COVID-19) pandemic on the incidence rates of injury in young elite football players.

DESIGN

A prospective cohort study design was adopted.

PARTICIPANTS

Our study included 832 male football players who suffered an injury during any of the six competitive seasons.

SETTING

An elite youth football academy.

MAIN OUTCOME MEASURE

Descriptive data and the incidence of injury were calculated. A generalized linear mixed model was used to assess differences in the occurrence of injury among the various age groups. Joinpoint regression was used to analyze injury trends.

RESULTS

Joinpoint regression models showed a statistically significant decrease in the incidence of injury in all age groups with an average annual percent change (AAPC) of 13.9 (95 %Confidence Interval [CI]:-23.2 - 3.4) and -13.5 (95 %CI:-24.5 to -0.9) for models with zero and one joinpoint, respectively. Football players in older age groups sustain a higher number of injuries, probably due to a higher number of matches and greater training intensity.

CONCLUSION

This study showed a downward trend in injuries in the participants prior to the pandemic, with an evident increase in the incidence rate of injury during the COVID-19 pandemic.

The COVID-19 lockdown as a model of detraining in division 1 college softball players

BACKGROUND

The COVID-19 pandemic interrupted the organized training of softball players, similar to the abrupt cessation of sports participation that can happen after an injury. Thus, the COVID-19 pandemic offers a unique model to study how sudden detraining influences softball players.

METHODS

We recruited a sample of convenience of National Collegiate Athletic Association Division 1 softball players. They participated in three data collections: pre-lockdown (Jan 2020, T1), post-lockdown (Sept 2020, T2), and before the 2021 season (Jan 2021, T3). Between T1 and T2, players received an at-home conditioning and throwing program, but compliance was not strictly monitored. Between T2-T3, players resumed formal fall training (team-organized workouts, on-field practice, and within-team scrimmage games). At each time point, we collected bilaterally: 1) shoulder internal rotation (IR) and external rotation (ER) range of motion (ROM); 2) shoulder IR and ER strength; 3) hip IR and ER ROM; and 4) hip abduction and extension strength. We used four independent (2 Sides × 3 Timepoints) MANOVA with repeated measures; we followed up significant MANOVA main effect of time with Sidak posthoc tests for pairwise comparisons between time points.

RESULTS

Fifteen players participated in this study. We found a significant MANOVA main effect of time for shoulder and hip ROM (p < 0.01). Between T1-T2, dominant shoulder ER ROM decreased 6.5°, dominant shoulder IR ROM increased 4.3°, and lead hip IR ROM increased 4.4°. Between T2-T3, dominant shoulder ER ROM increased 6.3° and trail hip ER ROM increased 5.9°. We found a significant MANOVA main effect of time for shoulder strength (p = 0.03) but not for hip strength (p = 0.18). Between T2-T3, non-dominant shoulder IR and ER increased 1.8 kg and 1.5 kg, respectively.

CONCLUSION

A sudden and prolonged cessation of organized training generated changes in shoulder and hip ROM but affected strength to a lesser extent. The loss of shoulder ER and increased lead hip IR ROM are maladaptive as they are associated with injury in overhead athletes. Resuming team-organized training and scrimmage reversed some (shoulder ER), but not all of these changes. Practitioners should monitor clinical variables regularly and be aware of potential changes due to unexpected and prolonged interruptions in training, such as when players suffer sports-related injuries.

A musculoskeletal multifactorial individualised programme for hamstring muscle injury risk reduction in professional football: results of a prospective cohort study

Objective

To test whether a musculoskeletal multifactorial and individualised hamstring muscle injury (HMI) risk reduction programme could reduce HMI risk in professional football.

Methods

We conducted a prospective cohort study in Finnish premier football league teams, with the 2019 season used as a control and an intervention conducted in the 2021 season. Screening was conducted to provide individualised programmes and monitor progress. Cox regression with hazard ratio (HR) was used with HMI as outcome and season as explanatory variable, including all players for primary analysis and those who performed the two seasons for secondary analysis.

Results

90 players were included in the control and 87 in the intervention seasons; 31 players performed in the 2 seasons. Twenty HMIs were recorded during the control and 16 during the intervention seasons. Cox regression analyses revealed that HMI risk at any given time was not significantly different between control and intervention seasons (for all players: HR 0.77 (95% CI 0.39 to 1.51), p=0.444; for the 31 players: HR 0.32 (95% CI 0.01 to 1.29), p=0.110)). For the 31 players, the HMI burden was significantly reduced in the intervention compared with the control season (RR 0.67 (95% CI 0.53 to 0.85)). Higher compliance with knee strength training, maximal velocity exposure and lower performance reductions in maximal theoretical horizontal force and knee flexor force were associated with lower HMI incidence.

Conclusions

Although the primary analysis did not reveal any significant effect of the intervention to reduce HMI risk in professional football, the programme was feasible, and additional secondary analyses showed a significant association between the intervention and lower HMI burden, incidence and risk.

'Benched' the effect of the COVID-19 lockdown on injury incidence in sub-elite football in Australia: a retrospective population study using injury insurance records

OBJECTIVES

The primary aim of this study was to compare injury rates pre- and post-COVID-19 lockdown in sub-elite football (soccer) players by analysing the full season and the first month of each season between 2018 and 2020. Secondary aims were to describe the incidence, location and type of injuries and to compare injuries by age group and sex.

DESIGN

Descriptive epidemiological study.

METHODS

A de-identified insurance database was retrospectively coded using the Orchard Sports Injury Classification System. Injury incidence per 1000 hours as well as incidence rate ratios (IRR) with confidence intervals were calculated.

RESULTS

No significant difference was found in the overall incidence rate in 2020 compared with the 2018 and 2019 seasons (IRR, 1.04 [95% CI, 0.96-1.13]; p = 0.294). However, overall injuries increased by 26% (IRR: 1.26 [95% CI 1.07-1.47]; p < 0.005) and joint sprains increased by 45% (IRR: 1.45 [95% CI 1.14-1.84]; p < 0.005) in the first month of 2020 compared with 2018-2019. Between 2018 and 2020, there were 4149 injury insurance claims, with anterior cruciate ligament (ACL) ruptures accounting for 19% of all injuries. When comparing sex, female players had significantly more ankle sprains whilst male players suffered more dental injuries.

CONCLUSIONS

This study adds to a growing body of evidence investigating injury rates post-COVID-19 lockdowns in sport. Sub-elite players appear to be at higher risk of joint injuries within the first month of training following a period of lockdown. Overall, stakeholders involved in sub-elite football should prioritise knee and ankle joint injury prevention.

Running Habits and Injury Frequency Following COVID-19 Restrictions in Adolescent Long-Distance Runners

PURPOSE

A decline in youth running was observed at the start of the COVID-19 pandemic. We investigated whether the resumption of organized running after social distancing restrictions changed running habits or injury frequency in adolescent runners.

METHODS

Adolescents (age = 16.1 [2.1] y) who participated in long-distance running activities completed an online survey in the Spring and Fall of 2020. Participants self-reported average weekly running habits and whether they sustained an injury during the Fall 2020 season. Poisson regression models and 1-way analysis of variance compared running habits while Fisher exact test compared differences in frequencies of injuries during Fall 2020 among season statuses (full, delayed, and canceled).

RESULTS

All runners, regardless of season status, increased weekly distance during Fall 2020. Only runners with a full Fall 2020 season ran more times per week and more high-intensity runs per week compared with their Spring 2020 running habits. There were no differences in running volume or running-related injury frequency among Fall 2020 season statuses.

CONCLUSIONS

There were no significant differences in running-related injury (RRI) frequency among runners, regardless of season status, following the resumption of cross-country. Health care providers may need to prepare for runners to increase running volume and intensity following the resumption of organized team activities.

New insights from Norwegian and Swedish sports coaches' employment, practices, and beliefs during the first COVID-19 restriction period

Introduction

This study (i) examined Norwegian and Swedish sports coaches' employment, practices, and beliefs during the first wave of the COVID-19 pandemic, (ii) compared these aspects between coaches in Norway and Sweden, two countries with clearly different movement restrictions strategies in this period.

Methods

An online survey was distributed to coaches via email and social media. The survey was open between June and August 2020. In total, 348 coaches responded, 141 from Norway, and 207 from Sweden.

Results

Among responders, 2% had lost their job due to the pandemic, 17% had been furloughed, 28% worked from home office, and 39% worked as usual. Norwegian coaches were more likely to work from home (48% vs. 15%, p < .001), while Swedish coaches were more likely to work as usual (60% vs. 9%, p < .001). Coaches in both countries communicated less frequently with their athletes (p < .001) and had less in-person communication (p < .001) compared to pre-Covid levels. Larger declines existed among Norwegian coaches regarding communication frequency (p < .001) and in-person communication (p < .001). Video calls and phone calls usage increased (p < .001 and p = .009 respectively). We recorded low levels of concern among coaches about the effects of the pandemic on their relationship with their athletes. There were considerable levels of concern about athletes' maintaining their motivation to train (Norway: 43.3%, Sweden: 50.7%), and low levels of concern about the coaches' relationships with their athletes (Norway: 14.1%, Sweden: 17.8%).

Discussion

Overall, this study showed the imposed movement restrictions had several negative consequences for the employment and work practices of sports coaches in Norway and Sweden. However, it also highlighted that coaches were able to adapt their work practices to the constraints and were able to maintain relationships with their athletes. The consequences raised in this paper can act as a guide during possible future lockdowns.

Changes in the incidence of stress reactions and fractures among intercollegiate athletes after the COVID-19 pandemic

PURPOSE

The purpose of this study was to characterize the impact of detraining due to the COVID-19 pandemic on incidence of bony injuries and stress fractures in collegiate athletes.

METHODS

A comprehensive collegiate athletic conference injury database was queried for all in-season, sport-related bony injuries (defined as all stress reactions and fractures) that occurred across all sports from January 2016 to June 2021. The bony injury rate per 1000 athlete exposure hours (AEH) was calculated and compared between the immediate post-hiatus season and historic rates from pre-hiatus seasons (2016-2019). Injury characteristics were also compared between the pre- and post-hiatus time periods.

RESULTS

A total of 868 bony injuries across 23 sports were identified. The sports with highest overall baseline bony injury rates in historic seasons were women's cross country (0.57 injuries per 1000 AEH) and men's cross country (0.32). Compared to historic pre-hiatus rates, female cross-country runners demonstrated a significantly lower bony injury incidence rate in the post-hiatus season (0.24 vs. 0.57, p = 0.016) while male swimming athletes demonstrated a statistically significant increase in bony injury rate (0.09 vs. 0.01, p = 0.015). The proportion of bony injuries attributed to repetitive trauma increased; while, the proportion of injuries attributed to running decreased between the pre- and post-hiatus seasons.

CONCLUSION

Across all sports, there was no consistent trend toward increased rates of bony injury in the immediate post-hiatus season. However, female cross-country runners demonstrated lower rates of bony injury in the post-hiatus season while male swimmers demonstrated higher rates. Furthermore, bony injuries in the post-hiatus season were more likely to be the result of repetitive trauma and less likely to be from running.

LEVEL OF EVIDENCE

Level III, retrospective, cross sectional study.

Soccer's AI transformation: deep learning's analysis of soccer's pandemic research evolution

Introduction

This paper aims to identify and compare changes in trends and research interests in soccer articles from before and during the COVID-19 pandemic.

Methods

We compared research interests and trends in soccer-related journal articles published before COVID-19 (2018-2020) and during the COVID-19 pandemic (2021-2022) using Bidirectional Encoder Representations from Transformers (BERT) topic modeling.

Results

In both periods, we categorized the social sciences into psychology, sociology, business, and technology, with some interdisciplinary research topics identified, and we identified changes during the COVID-19 pandemic period, including a new approach to home advantage. Furthermore, Sports science and sports medicine had a vast array of subject areas and topics, but some similar themes emerged in both periods and found changes before and during COVID-19. These changes can be broadly categorized into (a) Social Sciences and Technology; (b) Performance training approaches; (c) injury part of body. With training topics being more prominent than match performance during the pandemic; and changes within injuries, with the lower limbs becoming more prominent than the head during the pandemic.

Conclusion

Now that the pandemic has ended, soccer environments and routines have returned to pre-pandemic levels, but the environment that have changed during the pandemic provide an opportunity for researchers and practitioners in the field of soccer to detect post-pandemic changes and identify trends and future directions for research.

The Effects of Modified Game Schedules on Injury Rates in the National Hockey League (NHL)

Background Due to the COVID-19 pandemic, many professional sports leagues such as the National Hockey League (NHL) made significant changes to their schedules and operating procedures. Changes included a modified 2019-2020 playoff format, the removal of the 2020-2021 preseason, and condensed game schedules. Though these modifications were made in an effort to protect players from COVID-19, they resulted in decreased training time and preparation. The purpose of this study was to assess the impact of these changes on the rate of player injuries in the NHL both after the resumption of the midseason stoppage and during the subsequent seasons. Hypothesis/purpose Changes to the NHL schedule amid the COVID-19 pandemic resulted in a significant increase in player injury rates. Methods NHL injuries were obtained from an NHL injury database for the 2018-2019 through the 2021-2022 seasons. The date of injury, date of return, injury description, player age, and player position were recorded. Injury rates were calculated as the number of total athlete injuries per 1000 game exposures (GEs). The primary outcome was the injury proportion ratio (IPR) when comparing the injury rates of the post-COVID-19 season with baseline seasons. Secondary measures analyzed injuries based on age, anatomic location, month in the season, position, length of injury, season-ending injuries, and recurring injuries. Results A total of 4604 injuries were recorded between 2018 and 2022. The modified 2019-2020 playoffs had significantly higher rates of injury (IPR = 1.84, 95% confidence interval {CI} = 1.36-2.49) with more game exposures per week. The 2020-2021 season had significantly higher rates of overall player injury compared to baseline seasons (IPR = 1.19, 95% CI = 1.09-1.30) and also had a higher rate of season-ending injuries (IPR = 1.71, 95% CI = 1.38-2.11). Most injuries occurred in the first few months of the 2020-2021 season. There was no significant difference in injury rate based on age group and no significant difference in the average length of injury between seasons. Conclusion Increases in injury rates could be due to decreased offseason training between seasons, the elimination of preseason games, and increased game density. Decreasing typical training timelines and eliminating the preseason to rapidly return to normal competition after unexpected events (pandemics, lockdowns, etc.) may pose a risk to player safety in the NHL. These findings should be considered before future schedule changes in professional hockey.

Impact of COVID-19 lockdown on injury risk in Qatar's professional football

OBJECTIVES

To compare injury incidence, burden and characteristics between the pre- and post-COVID-19 lockdown periods in Qatari professional football.

DESIGN

Prospective cohort study.

METHODS

Injury and exposure data for two post-COVID-19 lockdown periods [early post-lockdown period: short-term ~2 months (54 matches) and late post-lockdown period: long-term 8-months (183 matches)] were compared to the benchmark of the same periods from the three previous seasons (2017/18-2019/20).

RESULTS

We observed no difference in overall, training or match incidence between early post-lockdown period and the benchmark reference. However, this short-term period resulted in lower burden for overall- (RR 0.80, P < 0.0001), training- (RR 0.73, P < 0.0001) and match-injuries (RR 0.40, P < 0.0001) compared to the benchmark. During late post-lockdown period match injury incidence (RR 0.72, P = 0.0010) and match injury burden (RR 0.69, P < 0.001) were lower than the benchmark. In contrast, both overall- (RR 1.30, P < 0.001) and training-injury burden (RR 1.65, P < 0.001) were higher. A significant increase in adductor strains in both post-lockdown periods was observed.

CONCLUSIONS

Immediately after the COVID-19 lockdown (short-term effect), there was no difference in injury incidence but a lower injury burden compared to benchmark. Moreover, the rapid return to competition for the successive season (long-term effect) was associated with a higher overall- and training-injury burden, but a lower match-injury burden compared to the benchmark.

SARS-CoV-2 Infection Increases the Risk of Muscle Injury in Professional Male Soccer Players-A Retrospective Analysis of the Italian and Spanish Major Leagues

A retrospective cohort study on professional soccer players from the Serie A and LaLiga was conducted to investigate the correlation between SARS-CoV-2 infection and muscle injuries. Players were divided into two groups based on whether they contracted the SARS-CoV-2 infection (C+) or not (C-) during the 2020/2021 season. In the 2019-2020 season, both championships showed a similar number of muscular injuries (MI) between C+ and C- (Serie A: p = 0.194; 95% CI: -0.044 to 0.215, LaLiga p = 0.915; 95% CI: -0.123 to 0.137). In the 2020-2021 season, C+ had a significantly higher number of MI compared to C- in both championships (Serie A: p < 0.05; 95% CI 0.731 to 1.038; LaLiga: p < 0.05; 95% CI: 0.773 to 1.054). Multiple linear regression analysis confirmed that belonging to C+ in the season 2020/2021 was the variable that most strongly influenced the probability of having a muscle injury. Survival analysis revealed a hazard ratio of 3.73 (95% CI 3.018 to 4.628) and of 5.14 (95% CI 3.200 to 8.254) for Serie A and LaLiga respectively. We found an association between SARS-CoV-2 infection and increased risk of muscle injury, emphasizing the importance of carefully considering the infection in the decision-making process for returning to sport. Therefore, SARS-CoV-2 infection should be judged as a real injury requiring specific assessment and training programs.

Return to sport in elite gymnastics: Unprecedented training interruptions provide lessons for the future

INTRODUCTION

Year-round training is standard for elite gymnasts in the United States, but the coronavirus disease 2019 (COVID-19) pandemic led to unprecedented training interruptions. The effect of these training disruptions is unknown.

OBJECTIVE

This study aimed to describe and compare training interruptions in elite gymnasts before and during the pandemic, the time it took to return to the prior level of gymnastics training, the development of injuries during return to gymnastics training, and gymnast-reported difficulty in and nervousness about returning to prior level of gymnastics training.

DESIGN

Retrospective study.

SETTING

Anonymous online surveys distributed to elite gymnasts in the United States.

PARTICIPANTS

A total of 184 current elite gymnasts who completed the surveys were included. This represented an overall response rate of 52.3% (184/352).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Information was collected about training interruptions and time, nervousness, difficulty, and injury during return to gymnastics.

RESULTS

Gymnasts reported significantly longer training interruptions due to COVID-19 than before the pandemic (8.7 ± 4.4 vs. 4.4 ± 7.9 weeks, p < .001), but duration of return to prior gymnastics level was similar (4.6 ± 2.7 vs. 3.7 ± 4.8 weeks, p = .106). Of the 137 gymnasts who had returned to training by the time of the survey, 46 (33.6%) reported an injury during their return to gymnastics. A high degree of nervousness to return to gymnastics was significantly associated with greater risks of injury upon return (risk ratio [RR] 2.7, 95% confidence interval [CI]: 1.6-4.7; p < .001) and difficulty returning to prior level (RR 3.4, 95% CI: 1.7-6.6; p < .001).

CONCLUSION

Pandemic-related training interruption was significantly greater in duration than prior interruptions, but time required for return to gymnastics was similar. Gymnasts may be at increased risk of injury during return to gymnastics if experiencing nervousness about returning following a break in training. These findings provide guidance for gymnasts' return from training interruptions and may refute the long-held belief that gymnasts should not take time away from training due to fear of injury or difficulty regaining skills.

Bone Stress Injuries at the Ankle and Foot

Bone stress injuries (BSIs) are a frequent finding in athletes, particularly of the foot and ankle. A BSI is caused by recurring microtrauma to the cortical or trabecular bone exceeding the repair capacity of normal bone. The most frequent fractures at the ankle are low risk, characterized by a low risk for nonunion. These include the posteromedial tibia, the calcaneus, and the metatarsal diaphysis. High-risk stress fractures have a higher risk for nonunion and need more aggressive treatment. Examples are the medial malleolus, navicular bone, and the base of the second and fifth metatarsal bone.Imaging features depend on the primary involvement of cortical versus trabecular bone. Conventional radiographs may remain normal up to 2 to 3 weeks. For cortical bone, early signs of BSIs are a periosteal reaction or the "gray cortex sign," followed by cortical thickening and fracture line depiction. In trabecular bone, a sclerotic dense line may be seen. Magnetic resonance imaging enables early detection of BSIs and can differentiate between a stress reaction and a fracture. We review typical anamnestic/clinical findings, epidemiology and risk factors, imaging characteristics, and findings at typical locations of BSIs at the foot and ankle that may help guide treatment strategy and patient recovery.

Epidemiology of Rugby-Related Injuries Presenting to the Emergency Department: A 10-Year Review

Background Rugby is a popular contact sport played with little to no protective clothing. There exist few comprehensive studies investigating emergency department (ED) visit patterns for rugby-related injuries.We hypothesize that male athletes remain the most common patient demographic to present to the ED with rugby-related injuries and that the number of patients diagnosed with soft tissue injuries such as sprains and strains decreased during the COVID-19 pandemic. Methodology The National Electronic Injury Surveillance System database was examined for rugby injuries from January 2012 through December 2021. Cases were stratified by sex, age, and injury type to monitor epidemiological patterns. This is a descriptive epidemiology study. Level of evidence III. Results A total of 2,896 individuals with rugby-related ED visits were identified. ED patients were most common among males (73.9%), Caucasians (45.3%), and in the 15-19-year-old age range (44.9%). Injuries most commonly affected the upper body, specifically the head (23.1%), face (13.8%), and shoulder (12.4%) with fractures and sprains comprising 22.3% and 18.5% of ED diagnoses, respectively. Concussions were the most frequent injury to any one body part (11.2%). During the COVID-19 pandemic, ED patients with rugby-related injuries were significantly more likely to be males presenting with lacerations or hemorrhages. ED visits for sprains and strains significantly decreased in the peri-COVID-19 period. Conclusions Annual ED visits due to rugby injuries are declining. The head and neck are the most common sites of injuries. Decreased presentation to the ED during the COVID-19 pandemic may raise concern for the potential for untreated injuries. Physicians should anticipate the presence of chronic sports-related injuries when evaluating future patients.

Impact of the COVID-19 Pandemic Hiatus From Sports Activities on Injuries Observed Among Division I NCAA Athletes

Background

The coronavirus disease 2019 (COVID-19) pandemic significantly disrupted athletic activities, including those in the Pacific 12 (Pac-12) Conference of the National Collegiate Athletic Association. It is currently unknown how the disruption in training and competition impacted athletes' risk of injury upon resumption of activities.

Purpose

To describe and compare the rate, timing, mechanism, and severity of injuries among collegiate athletes across multiple sports in the Pac-12 Conference before and after the COVID-19 pandemic-associated hiatus of intercollegiate athletic activities.

Study Design

Descriptive epidemiology study.

Methods

Descriptive and injury data among intercollegiate athletes from both the season before the hiatus and the season after the hiatus were acquired from the Pac-12 Health Analytics Program database. Injury elements (timing of injury onset, injury severity, mechanism, recurrence, outcome, need for procedural intervention, and event segment during which the injury took place) were compared by time using the chi-square test and a multivariate logistic regression model. Subgroup analyses were performed on knee and shoulder injuries among athletes participating in sports with traditionally high rates of knee and shoulder injuries.

Results

A total of 12,319 sports-related injuries across 23 sports were identified, with 7869 pre-hiatus injuries and 4450 post-hiatus injuries. There was no difference in the overall incidence of injury between the pre-hiatus and post-hiatus seasons. However, the proportion of noncontact injuries was higher in the post-hiatus season for football, baseball, and softball players, and the proportion of nonacute injuries in the post-hiatus season was higher among football, basketball, and rowing athletes. Finally, the overall proportion of injuries sustained by football players in the final 25% of competition or practice was higher in the post-hiatus season.

Conclusion

Athletes competing in the post-hiatus season were observed to have higher rates of noncontact injuries and injuries sustained in the final 25% of competition. This study demonstrates that the COVID-19 pandemic has had varied effects on athletes from different sports, suggesting that many factors must be considered when designing return-to-sports programs for athletes after an extended absence from organized training.

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, CI_95% 1.05; 1.77, p-value = 0.02). The injury burden demonstrated an 86% increase (ratio = 1.86, CI_95% 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, CI_95% 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%, CI_95% 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.

Injury rates in the National Football League during the 2020 COVID-19 season

OBJECTIVES

The National Football League (NFL) altered the 2020 season due to the COVID-19 pandemic, which resulted in canceled preseason games and a dynamic regular season schedule to accommodate for canceled games. The purpose of this study was to evaluate if the disrupted training and preseason schedule lead to increased injury rates as seen in other professional sports. We hypothesized that the overall injury rate would be higher in the 2020 season compared to the 2018-2019 seasons and that this increase will affect all body regions equally.

METHODS

Publicly released NFL weekly injury reports were queried to identify players listed as out or placed on the injured reserve for at least one game in the 2018-2020 seasons. Injuries were categorized into upper extremity, lower extremity, spine/core, head, illness, not injury related and undisclosed injuries. Incidents per 1000 athlete exposures were calculated for the prior two seasons (2018-2019) and for the 2020 season separately. Percentage of injuries occurring in each position was calculated separately for the pre-COVID-19 (2018 and 2019) and post-COVID-19 (2020) cohorts. Incidence rate ratios (IRR) and confidence intervals were used to compare injury rates in 2018-2019 versus 2020. The z-test for proportions was used to determine significant differences between injury incidences.

RESULTS

The overall incidence rate per 1000 athlete exposures in 2020 was not significantly different compared to pre-COVID-19 seasons (21.6 versus 23.1, IRR 0.94, 95% CI: 0.9-1.0 p > 0.999). The proportion of injuries by position did not change before and after COVID-19 either (p > 0.999). Out listings due to illness were significantly increased during the 2020 season (0.8 versus 0.3, IRR 2.8, 95% CI: 1.4-5.2, p = 0.004).

CONCLUSION

The incidence of NFL injuries did not significantly change in 2020. The distribution of injuries did not change with respect to position.

Effects of the COVID-19 confinement period on hip strength, flexibility and muscle injury rate in professional soccer players

OBJECTIVES

This study aimed to examine the effects of COVID-19 confinement on hamstring eccentric strength, hip adduction-abduction strength, and posterior chain flexibility in professional male soccer players. We also aimed to investigate whether muscle strength and flexibility would change when the players returned to play after COVID-19 confinement.

METHODS

Thirty professional male soccer (Age; 24.9 ± 4.8 yrs, BMI; 22.7 ± 1.4 kg/m²) players participated in this study. Hamstring eccentric strength, hip abduction-adduction strength and posterior chain flexibility (PCF) were measured before (time 1) and after the home confinement period (time 2) and after return to play (time 3). Repeated measures of ANOVA was used for statistical analysis.

RESULTS

PCF decreased from time 1 to time 2 (p = 0.005) but it increased from time 2 to time 3 (p = 0.03). Hamstring eccentric strength decreased from time 1 to time 2 for both dominant (p = 0.002) and non-dominant (p = 0.04) limbs and no difference was observed between time 2 and time 3 (p > 0.05). Hip abductor and adductor strength did not change between time 1 and time 2 (p > 0.05) but they increased from time 2 and time 3 in the dominant limb (p < 0.05). Five players (16%) had muscle injuries including hamstrings and adductors when they returned to play.

CONCLUSION

This study showed that 8-week COVID-19 confinement had an adverse effect on hamstring eccentric strength and PCF and 3 players had hamstring muscle injuries when they returned to play. Therefore, soccer players can be at risk of hamstring muscle injuries due to long-term detraining. Hip abductor and adductor strength seem not to be negatively affected by 8-week COVID-19 confinement. However, 2 players had adductor strain when they returned to play.

Impact and control of the COVID pandemic in an elite sports club: Real Madrid

The incidence and risk factors for poor outcome in patients with COVID are well known, as are the protective measures in high-risk populations. In contrast, the epidemiological and clinical behavior of this disease in the population of elite athletes who are the paradigm of good health is poorly understood. Data on COVID in athletes are scarce and have focused preferentially on the consequences on sports performance of confinement measures and on the pathophysiological risks of infected athletes. Real Madrid is a large elite sports institution with facilities in the City of Madrid where 600 athletes train daily. The incidence of COVID during a study period of 671 days of observation in athletes, professional or amateur, working in the institution has been 0,74 per 1,000 days of exposure. The disease has been asymptomatic or oligosymptomatic in all athletes and did not require any hospital admissions. The different teams did not have to suspend any of its sportive commitments for COVID during the study period and there was no evidence of outbreaks of internal transmission between members of the different teams.

The Five-substitution Option Enhances Teams' Running Performance at High Speed in Football

The aim of this investigation was to describe how the introduction of the five-substitution option affected football teams' running performance. A comparative analysis was performed in 17 professional football teams for the 2019-2020 (up to three substitutions) vs 2020-2021 (five substitutions option) seasons in LaLiga. The five-substitution option increased the number of substitutions (from 2.9±0.1 to 4.2±1.0 substitutions/match, respectively; p<0.01, Effect Size (ES)=2.11) but it did not change the time selected for the first substitution (from 57.5±13.0 to 56.2±13.7 min; p=0.06, ES=0.1). Total running distance was similar between seasons but running distance at 21.0-23.9 km/h (from 3.0±0.4 to 3.2±0.4 km; p=0.01, ES=0.6) and at≥24.0 km/h (from 3.0±0.6 to 3.2±0.5 km; p=0.01, ES=0.3) were higher with the five-substitution option. These increases were associated with a higher distance covered by starting players (p<0.05) rather than an effect of substitute players.: With the five-substitution option, team coaches increased the number of substitutions per match which enhanced the possibilities of the team's staff to manage players' physical load. The five-substitution option allowed also increased running performance at≥21.0 km/h during the matches.

Effects of high-intensity interval training versus sprint interval training during the second wave of COVID-19 lockdown on soccer players

This study aimed to compare the effects of two intervention programs (i.e., high-intensity interval training [ΗΙΙΤ] versus sprint interval training [SIT]) during the second wave of pandemic COVID-19 in semi-professional soccer players. Twenty-nine male soccer players were divided into two groups: HIIT (N: 16, age: 19.6 ± 2.4 years, height: 1.8 ± 0.5 m, weight: 71.5 ± 4.6 kg, and body fat: 7.3 ± 2.6%), who performed a HIIT protocol with progressive intensity and resistance training; SIT (N: 13, age: 23.5 ± 5.1 years, height: 1.8 ± 0.1 m, weight: 74.0 ± 4.5 kg and body fat: 8.8 ± 2.6%) that performed a SIT program combined with body weight circuit training. According to the instructions from World Health Organization of basic protective measures against COVID-19, each session did not exceed 60 min. Aerobic capacity (Yo–Yo IR1) and countermovement jump (CMJ) height were measured before and after a 4-week intervention period. Aerobic variables (maximum oxygen uptake [V̇O2max], velocity at V̇O2max [vV̇O2max] and CMJ significantly increased (p <0.001), while maximum heart rate [HRmax] decreased (p <0.01) following the HIIT intervention program. Conversely, values remained unchanged in the SIT group after the training. Post-evaluation between-group comparisons revealed that V̇O2max was significantly higher in HIIT when compared to SIT (p <0.05). These results suggest that HIIT combined with resistance training, in different sessions, could lead to superior improvements in endurance and vertical jump ability in short time periods when compared to the combination of SIT and body-weighted strength training in semi-professional soccer players.

Effects of COVID-19 Sport Suspension on Injury Rates in Elite Athletes: A Critically Appraised Topic

Clinical Scenario: With the enforcement of COVID-19 lockdown restrictions, sports teams worldwide were required to make drastic adjustments to their training regimen. This prolonged sport suspension resulted in a significant decrease in off-season and preseason training periods. Clinical Question: Are professional athletes who experienced a sport suspension during the COVID-19 pandemic at a higher risk of injury once they return to competition compared with pre-COVID-19 seasons? Summary of Key Findings: The literature was searched for articles examining the effects of COVID-19 sport suspension on athletic injury rates in elite athletes. A total of 240 articles were retrieved, and after exclusion criteria and removal of duplicates, four retrospective cohort studies remained. An increase in injury rates across studies after their sport suspension compared with pre-COVID-19 seasons was found. Clinical Bottom Line: The extended suspension from physical activity increased the risk of injury as players returned to sport training post-COVID-19 restrictions. While these studies demonstrated the effects on elite-level athletes, prolonged sport suspension may impact different patient populations. Strength of Recommendation: Based on the Strength of Recommendation Taxonomy Scale, this critically appraised topic received a B grade for consistent but limited-quality patient-oriented evidence, with a low number of articles included.

A Study on the Injury Rate of Spanish Competitive Athletes as a Consequence of the COVID-19 Pandemic Lockdown

The COVID-19 lockdown may have had collateral effects on the conditions of athletes, with possible increases in injury risks upon the return to sports. Due to the existence of multiple factors of injury risks based on the lockdown and the return to sports, the aim of this study was to analyze the injury rates after the lockdown in competitive athletes. A non-experimental quantitative design based on a survey was carried out, and 94 athletes (42 males and 52 females; 23.57 ± 6.20 years) participated. Statistical analyses were carried out using non-parametric tests. Injury rates did not increase significantly after the lockdown, and there were no statistical differences between performance levels, types of sports, the design of a specific training program by sports professionals during the lockdown, the moment of injury, and the mechanism of injury. It is important to develop injury prevention protocols to prepare athletes after such a long period of detraining.

Coach leadership in a crisis context: Investigating effective coach behaviors during the COVID-19 pandemic with a process view

Introduction

Drawing from the crisis leadership conceptualization, this study aims to investigate coaches' opinion patterns on effective leadership behaviors during the COVID-19 pandemic. The study used a process view to explore how coaches as leaders act in pre, during, and post-crisis phases.

Method

Thirty-two fulltime professional coaches (28 males and 4 females) from individual and team sports who experienced the entire COVID-19 pandemic from January 2020 to July 2021 in the United Kingdom were invited to express their perceptions of effective leadership behaviors. The study used Q methodology to analyze coaches' perceptions and experiences.

Result

The study revealed that the most effective coach leadership behaviors occurred during-crisis phase, which has the most positive ratings (n = 48) compared to the pre-and post-crisis phases (n = 18). The study's main findings highlighted different phases of the COVID-19 pandemic demand various effective countermeasures from coaches. These practical and successful experiences were summarized as: division of labor, athlete-centered, team-driven, consulting, safe environment, and online coaching.

Discussion

The findings of this study further highlight (1) the importance of coach leadership in creating a safe environment as it provides a much better platform to prepare for a pre-crisis stage, (2) that coaches should employ more positive than negative behaviors while interacting with team members more frequently especially during the crisis period, reducing athletes' negative feelings such as anxiety and worry, and (3) that the online training-related activities and interactions during the crisis time can be expanded to noncrisis times, as a crisis event can have positive implications for the future if handled properly.

COVID-19 modifications of offseason and preseason training for NFL athletes are associated with increased risk of regular season injuries

OBJECTIVES

COVID-19 altered National Football League (NFL) player and team training during the 2020 offseason. All preseason games were cancelled resulting in absence of game play before the first week of the regular season. Thus, concerns exist regarding injury susceptibility of players during regular season games. The purpose of this study was to evaluate and compare injury rates during the 2020 NFL season versus injury rates from the unaffected 2017-2019 seasons. We hypothesized there would be an increased injury rate and an increased rate of season ending injuries during the modified 2020 season.

METHODS

The NFL's public injury database was queried to identify players placed on the injury lists throughout the 2017-2020 seasons. All players listed as "out" and on the injured reserve due to physical injury were included in the data set. For further stratification, injury incidence was separated based on position. Time missed due to COVID-19 illness was not included. Injury rates were expressed as injuries per 1000 athlete exposures (AE).

RESULTS

Overall, 893 individual players missed games due to injury during the 2020 NFL regular season compared to an average of 743 over the 2017-2019 seasons. Defensive players at all positions had a statistically significant increase in injury incidence from an average of 7.54 to 10.20 injuries per 1000 AE. Defensive backs were most affected with a 46% increase in players injured. There was no statistically significant difference in season ending injuries for any position.

CONCLUSIONS

The COVID-19 stricken 2020 NFL regular season saw an increased rate and incidence of injuries. Specifically, defensive players had a higher incidence of injury overall with defensive backs experiencing the greatest increase in injury rates.

Understanding Youth Athlete Motivation, Training, and Activity Progression During and After the COVID-19 Sports Interruption

Background

COVID-19 restrictions created a period of disrupted sports participation for youth athletes. The physical conditioning, sports training habits, and patterns of sports activity resumption upon returning to normal sports activity are currently unknown.

Purpose/Hypothesis

This study aimed to determine the extent to which youth athletes maintained their training levels during the early stages of the COVID-19 pandemic and understand the strategies that enhanced motivation and adherence to a training regimen while in isolation. A secondary aim was to analyze how youth athletes returned to activity and identify injuries associated with prolonged sports interruption.

Study Design

Observational / Survey Study.

Methods

A survey designed to determine activity changes, type of organized instruction, and athlete preferences for training support were distributed by email using snowball sampling methodology to athletes 14-21 years old who were involved in competitive sports when pandemic restrictions were enacted. As sports activities resumed, a follow-up survey was distributed to the same respondents to identify feelings of preparedness, training habits, and injuries.

Results

Of the155 subjects (mean age 16.1 ± 2 years, 64.5% female) that completed the initial survey, 98% reported a stoppage of in-person sports participation and 70% decreased their exercise/training volume, with 41% (n=63) reporting > 50% reduction. Most athletes (86%) received instruction from coaches, with written workouts (70%) being most common; however, most athletes (70%) preferred instructor-led, group training sessions. Of the 43 subjects that completed the follow-up survey (34% response rate), there was an increase in athletic exposures compared to mid-pandemic levels, and 25% reported sustaining a sports-related injury shortly after resuming sports activities.

Conclusions

Pandemic-related sports restrictions resulted in a significant reduction in youth athlete training and conditioning. Coaches attempted to maintain training via the use of written workouts; however, athletes preferred instructor-led, group training sessions. There was a rapid resumption of sports activities, which may have contributed to the high rate of injuries in this study.

Level of Evidence

3.

The Impact of the COVID-19 Pandemic on Orthopaedic Knee Procedures: A National Multicentered Analysis

Introduction: The coronavirus disease 2019 (COVID-19) pandemic strained the United States healthcare system, and associated policies resulted in the postponement or cancellation of many elective surgeries. While most orthopaedic surgeons are aware of how the pandemic affected their patients’ care, broader national trends in the operative treatment of orthopaedic knee pathology are poorly characterized. Therefore, the purpose of this study was to identify trends in orthopaedic knee procedures during the COVID-19 pandemic.

Methods: The TriNetX database was queried for orthopaedic knee procedures performed from March 2018 to May 2021. Procedures were classified as arthroplasty (total knee arthroplasty (TKA), revision total knee arthroplasty) or non-arthroplasty (tendon or ligament repair, fracture fixation). Procedural volume per healthcare organization was determined over five seasons from March 2020 to May 2021 and compared to overlapping pre-pandemic periods from March 2018 to May 2019. Descriptive analysis was performed, and comparisons were made using a Student’s T-test.

Results: Compared to the pre-pandemic period, there were significant decreases in primary TKA (p=0.016), femoral or entire tibial component revision TKA (p=0.005), and open treatment of femoral shaft fractures (p=0.007) in spring 2020. Procedural volume returned to baseline in summer 2020 through winter 2021. In spring 2021, primary TKA (p=0.017) and one component revision TKA (p=0.003) increased compared to the pre-pandemic period.

Conclusion: The greatest decrease in knee procedures occurred early in the pandemic. Rates of these procedures have since rebounded, with some exceeding pre-pandemic levels. Hospitals are now better able to accommodate orthopaedic surgical volume while continuing to care for patients with COVID-19.

LDA-based topic modeling for COVID-19-related sports research trends

Introduction

The COVID-19 pandemic could generate a turning point for introducing a new system for sports participation and business. The purpose of this study is to explore trends and topic structures of COVID-19-related sports research by analyzing the relevant literature.

Methods

Sports studies related to COVID-19 were collected in searching international academic databases. After the pre-processing step using the refinement and morpheme analysis function of the Net Miner program, topic modeling and social network analysis were used to analyze Journal Citation Reports found using the search term 'COVID-19 sports'.

Results

As a result, this study used subject modeling to reveal important potential topics in COVID-19-related sports research articles. 'Sports participation', 'elite players', and 'sports industry' were macroscopically classified, and detailed research topics could be identified from each division.

Conclusion

This study revealed important latent topics from COVID-19-related sports research articles using topic modeling. The results of the research elucidate the structure of academic knowledge on this topic and provide guidance for future research.

Injury characteristics in Norwegian male professional football: A comparison between a regular season and a season in the pandemic

The Coronavirus Disease-19 (COVID-19) pandemic forced the Norwegian male premier league football season to reschedule, reducing the fixture calendar substantially. Previous research has shown that a congested match schedule can affect injury rates in professional football. Therefore, we aimed to investigate whether the Norwegian premier league teams suffered more injuries in the more match congested 2020 season than in the regular 2019-season. We invited all teams having participated in both seasons to export their injury data. Only teams that used the same medical staff to register injuries in both seasons were included, and to maximize data comparability between seasons, we applied a time-loss injury definition only. Seven of 13 teams agreed to participate and exported their injury data. Both seasons had 30 game weeks, but the 2020 season was 57 days shorter than the 2019 season. The match injury incidence did not differ significantly [incidence rate ratio 0.76 (0.48-1.20; p = 0.24) in the 2020 season compared to the 2019 season. Furthermore, we found no differences in the number of injuries, days lost to injury, matches missed to injury, or injury severity. We could not detect any differences between the two seasons, suggesting the congested match calendar combined with the safety measures in the 2020 season can be a safe alternative in future seasons.

A Plague of Their Own: Injury Incidence Remains Elevated in the 2021 Major League Baseball Season Compared to Pre-COVID-19 Seasons

Background

Significant increases in injuries were observed in the 2020 Major League Baseball (MLB) season; these were attributed to an increased acute to chronic workload due to the interrupted preseason and compressed season during the coronavirus disease of 2019 (COVID-19) pandemic. In 2021, the MLB resumed its regular schedule.

Hypothesis/Purpose

The purpose of this study was to determine the injury incidence and epidemiology of the 2021 MLB season compared to the injury incidence in the 2020 season and pre-COVID-19 seasons. The hypothesis was that, with the return to normal preseason training, injury incidence in 2021 would return to pre-COVID-19 rates. Additionally, it was hypothesized that injury list (IL) placements at midseason 2021 would be decreased relative to 2020 due to the uninterrupted preseason yet increased at full season 2021 due to increased overall workload from 2020.

Study Design

Descriptive epidemiology study.

Methods

The MLB transactions database was searched for players placed on the IL between 2018 and 2021. Injuries were categorized by body part and player position. Incidence per 1000 athlete-exposures was calculated for the pre-COVID-19 (2018-2019), 2020, and 2021 seasons. The z test for proportions was used to determine significant differences between injury incidences.

Results

The injury incidence rate by midseason 2021 (9.32) compared to 2020 (8.66) was not significantly different (p=0.234). At full season 2021, injury incidence rate (8.69) was significantly higher than pre-COVID-19 seasons (5.13, p<0.001), but not 2020 (p=0.952). When comparing full season 2021 to 2020, increased foot/ankle (0.50 vs 0.14, respectively, p<0.001) and miscellaneous (1.92 vs 0.68, respectively, p<0.001) injuries were observed.

Conclusion

The overall injury incidence in 2021 was significantly higher than pre-COVID-19 seasons, and no significant difference was observed between both mid- and full season 2021 and 2020, refuting the hypotheses. This signifies that injury incidence remained elevated in the 2021 season despite resumption of preseason training and a regular season.

Level of Evidence

3.

Differences in Physical Match Performance and Injury Occurrence Before and After the COVID-19 Break in Professional European Soccer Leagues: A Systematic Review

BACKGROUND

Due to the COVID-19 pandemic, matches and soccer-specific training were suspended for several weeks, matches after resumption were congested, and substitutions per team and game increased from three to five.

OBJECTIVE

The aim of this review was to examine possible differences in physical match performance and injuries between before and after the COVID-19 induced break of matches and training in professional male European soccer leagues during the 2019/2020 season.

METHODS

A systematic search identified all scientifically peer-reviewed publications involving elite male soccer players competing in the European leagues which reported physical match performance variables such as total running distance and running distance at different speed zones and/or injury parameters pre- and post-COVID-19 induced break.

RESULTS

In total, 11 articles were included, which were coming from German Bundesliga, Polish Ekstraklasa, Croatian HNL, Spanish La Liga, and Italian Serie A. In all studies investigating the German Bundesliga, most parameters of physical match performance remained unaffected (0.08 ≤ p ≤ 0.82; - 0.15 ≤ ES 0.15), while studies investigating the Polish Ekstraklasa (p ≤ 0.03; - 0.27 ≤ ES - 0.18), Croatian HNL (p ≤ 0.04; - 1.42 ≤ ES ≤ 1.44), Spanish La Liga (p ≤ 0.017; - 0.32 ≤ ES ≤ 5.5), and Italian Serie A (p ≤ 0.014; - 1.01 ≤ ES 0.24) showed a decrease in most parameters of physical match performance after the COVID-19 break. Injury rates were only investigated by studies targeting the German Bundesliga and Italian Serie A. In the majority of studies (3 out of 4 studies), there occurred no difference in injuries between pre- and post-COVID-19 break (p > 0.05; ES = N/A).

CONCLUSION

Results indicate that Bundesliga teams maintained physical match performance during the 9-weeks break in matches and 3-weeks break in group training, whereas a longer match and group training interruption up to 15 weeks and 8 weeks, respectively, in the other leagues appeared to lead to a decreased physical match performance. Regarding injuries, we speculate that the increase in substitutions from 3 to 5 substitutions per game might prevent an increase in injury occurrence during matches. The underlying studies' results provide hints for possible upcoming unexpected interruptions with respect to optimal physical preparations for the resumption of matches and a congested schedule to maintain physical match performance, or for possible rule changes such as 5 instead of 3 substitutions to avoid physical overload during congested match schedules.

Does the Number of Substitutions Used during the Matches Affect the Recovery Status and the Physical and Technical Performance of Elite Women's Soccer?

The aim of this study was to compare the effect of a new rule for substitutions (four and five) with the rule before the COVID-19 pandemic (up to three) on recovery status, physical and technical performance, internal workload, and recovery process in elite women soccer players. Thirty-eight matches from 2019 to 2020 from the Brazilian Championships were analyzed. All data for the two conditions (≤3 and 4-5 substitutions) were compared using an independent t-test. The physical demands measured by a global positioning system (GPS) and the technical (obtained from Instat) and internal workload (rating of perceived exertion [RPE]) were assessed. The recovery process was measured by the total quality recovery (TQR) 24 h after each match. No differences were observed in any physical and technical parameters between 4-5 and ≤3 substitutions (p > 0.05). Moreover, 4-5 substitutions demonstrated lower RPE (p < 0.001) and workload-RPE (p < 0.001), higher TQR (p = 0.008), and lower time played by the player (p < 0.001), compared to ≤3. Thus, the new provisory rule for substitutions improved the balance between stress and recovery.

Sports Imaging of COVID-19: A Multi-Organ System Review of Indications and Imaging Findings

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in December 2019 in Wuhan, China. Although coronavirus disease-19 (COVID-19) affects every population group, the sports community and athletes require special consideration of the effects on cardiovascular, musculoskeletal, neurologic, and respiratory systems. A comprehensive understanding of imaging indications, findings, and features of COVID-19 supports appropriate imaging utilization and effective patient management and treatment.

PURPOSE

To review the spectrum of sports imaging in COVID-19 infection, organ system manifestations, vaccine effects, and complications in recreational and competitive athletes.

STUDY DESIGN

Narrative review.

LEVEL OF EVIDENCE

Levels 4 and 5.

METHODS

Based on a PubMed database search, studies describing the imaging findings of COVID-19 infection, organ system manifestations, vaccine effects, and complications in recreational and competitive athletes were included.

RESULTS

On March 11, 2020, World Health Organization officially declared COVID-19 a global pandemic. As of May 9, 2022, more than 515 million confirmed cases of COVID-19 were reported globally. While the multisystem effects of COVID-19 are incompletely understood, the role of imaging in diagnosing, monitoring, and prognosticating active disease, long-term effects, and complications is evolving. In the respiratory system, imaging plays an important role in diagnosing, characterizing, and monitoring pulmonary COVID-19 infections, barotrauma, and COVID-19-associated chronic pulmonary opacities and fibrotic-like lung changes. Ultrasonography, computed tomography, and magnetic resonance imaging aid in the timely diagnosis of ischemic, embolic, and thrombotic peripheral and central cardiovascular events, including deep venous thrombosis, pulmonary embolism, myocarditis, and stroke. COVID-19-associated musculoskeletal and peripheral nervous system manifestations include rhabdomyolysis and myonecrosis, plexus and peripheral neuropathies, Guillain-Barré syndrome, and shoulder injury related to vaccine administration.

CONCLUSION

In athletes, COVID-19 infections and associated effects on cardiovascular, musculoskeletal, neurologic, and respiratory systems require special consideration. With the increasing understanding of the multisystem effects of COVID-19, the role of imaging in diagnosing, monitoring, and prognosticating active disease, long-term effects, and complications is evolving. A comprehensive understanding of imaging indications, COVID-19 imaging features, and organ system effects aids in appropriate imaging utilization and effective patient management and treatments.

Injury Incidence Increases after COVID-19 Infection: A Case Study with a Male Professional Football Team

Background: The SARS-CoV-2 virus disease has caused numerous changes in sports routines in the last two years, showing the influence on an increase in sports injuries. The aim of this study was to prospectively analyze the incidence and characteristics of injuries in male professional football players diagnosed with COVID-19 when they return to play after recovering from this illness. Methods: Injury characteristics of professional male football players were recorded for the 2020−2021 season following the international consensus statement from the International Olympic Committee (IOC). SARS-CoV-2 infection in the football players was certified by PCR analysis. Injury epidemiology was compared in players infected by the SARS-CoV-2 virus before and after being diagnosed with COVID-19. Results: 14 players (53.8%) were diagnosed with COVID-19 during 2020−2021 season and 12 (46.2%) were not infected (controls). Only three (21.4%) had suffered an injury before being diagnosed with COVID-19. Eleven players (78.6%) had injuries after being diagnosed with COVID-19 (p < 0.001). Among the players diagnosed with COVID-19, injury incidence increased on their return to play after the infection (3.8 to 12.4 injuries/1000 h of exposure, p < 0.001). Additionally, injury incidence during training (10.6 vs. 5.1 injuries/1000 h of exposure, p < 0.001) and matches (56.3 vs. 17.6 injuries/1000 h of exposure, p < 0.001) was ~two-fold higher on return to play after COVID-19 compared to controls (33.4 vs. 17.6 injuries/1000 h of exposure, respectively, p < 0.001). Conclusions: Injury incidence in professional football players who had been infected by the SARS-CoV-2 virus significantly increased compared to the injury rates that these same players had prior to the illness. Additionally, the injury incidence was higher when compared to players who were not infected by the SARS-CoV-2 virus during the season, especially during matches.

Leadership experiences of elite football team physicians during the COVID-19 pandemic: a pilot study

Objectives

The purpose of this study was to explore the leadership experiences of elite football team physicians during the COVID-19 pandemic.

Methods

A pilot-study based on a cross-sectional design by means of an electronic survey was conducted. The survey relied on 25 questions divided into distinct sections including among others professional and academic experience, leadership experiences and perspectives.

Results

A total of 57 physicians (91% male; mean age: 43 years) gave their electronic informed consent and completed the survey. All participants agreed that the demands of their role had increased during the COVID-19 pandemic. Fifty-two (92%) participants reported that they felt they were expected to take more of a leadership role during the COVID-19 pandemic. Eighteen (35%) reported feeling under pressure to make clinical decisions which were not in keeping with best clinical practice. Additional roles, duties and demands expected of team doctors during the COVID-19 pandemic were subdivided into communication, decision-making, logistical, and public health demands.

Conclusion

The findings from this pilot study suggest that the way in which team physicians at professional football clubs operate has altered since the onset of the COVID-19 pandemic, with greater demands placed on leadership skills including decision-making, communication and ethical stewardship. This has potential implications for sporting organisations, clinical practice and research.

Impact of COVID on Sports Injury Patterns, Changes in Mental Well-Being, and Strategies to Prepare for Future Pandemics in Sport

ABSTRACT

This review describes the available evidence of the acute respiratory syndrome coronavirus 2 (SARS-CoV-2, referred to COVID-19) pandemic on musculoskeletal injury patterns and prevalence in athletes. A brief overview of the epidemiology of COVID-19 and prevalence in active populations from youth through professional are provided. Responses to COVID-19 regarding sport participation at regional, national, and international organizations are summarized. Downstream effects of complete or partial training shutdown on injury risk and mental health are discussed. Strategies to maintain athletic potential and overall well-being include maintaining safe access to training facilities and resources, implementation of injury prevention programs, organization of athlete support networks, and incorporation of resilience and coping training.

Consequences of the SARS-CoV-2 Infection on Anaerobic Performances in Young Elite Soccer Players

The COVID-19 pandemic required local confinement measures reducing sport practice with possible consequences on the athletes’ performances. Furthermore, anaerobic detraining was underestimated and poorly known in adolescents. This article aimed to assess the effects of SARS-CoV-2 infection and 1-month COVID-19 confinement on jump testing in young elite soccer players despite a 1-month multimodal training program followed by a 1-month soccer retraining period. Thirty-one elite soccer players aged 14 were included; 16 were infected by the SARS-CoV-2 and compared with 15 non-infected elite soccer players before and after 1 month of COVID-19 confinement, and after 1 month of a soccer retraining period. Squat jumps (SJ), countermovement jumps with (CMJs) and without arm swinging (CMJ) and multiple consecutive jumps (stiffness) were used to explore the anaerobic performances. Analysis of variance for repeated measures was used to compare the positive and negative SARS-CoV-2 groups, taking into account the confinement period (low training) and the retraining soccer period. The jump tests were not altered in the positive SARS-CoV-2 group compared to the negative SARS-CoV-2 group after confinement (SJ: 31.6 ± 5.6 vs. 32.7 ± 3.7; CMJ: 34.1 ± 6.9 vs. 34.2 ± 2.6; CMJs: 38.6 ± 6.8 vs. 40.3 ± 3.9; stiffness: 28.5 ± 4.3 vs. 29.1 ± 3.7) and at 1 month of this period (SJ: 33.8 ± 5.5 vs. 36.2 ± 4.6; CMJ: 34.7 ± 5.5 vs. 36.4 ± 3.5; CMJs: 40.4 ± 6.7 vs. 42.7 ± 5.5; stiffness: 32.6 ± 4.7 vs. 34.0 ± 4.3). The SARS-CoV-2 infection had no consequence on anaerobic performances assessed by jump tests in adolescent soccer players. The adolescents’ growth could explain the absence of alteration of jump performances during the COVID-19 confinement. These results can be useful to manage the recovery of the anaerobic fitness after SARS-CoV-2 infection occurring in adolescent athletes.

Influence of the COVID-19 Lockdown and Restart on the Injury Incidence and Injury Burden in Men's Professional Football Leagues in 2020: The UEFA Elite Club Injury Study

BACKGROUND

Studies on football and the coronavirus disease 2019 (COVID-19) have mainly focused on the lockdown consequences for player fitness, the resumption of football training, and how to safely restart the league play, but injury data are scarce.

OBJECTIVE

To describe the injury incidence and injury burden in men's professional football teams during the pandemic year of 2020.

METHODS

Nineteen teams in 12 countries prospectively registered data on player-exposure and time-loss injuries throughout 2020. All major football leagues were paused as a direct response to the pandemic in March 2020 and were thereafter completely cancelled or restarted after a lockdown interval of at least two months. Historical data from 43 teams in the same cohort during the five preceding years (2015-2019) were used as reference. Between-season and within-season comparisons were made for injury incidence (number of injuries per 1000 h) and injury burden (number of absence days per 1000 h) with 95% confidence intervals and interquartile ranges.

RESULTS

There was no increased match injury incidence or injury burden following the restart in 2020 compared with other time periods of 2020 and the corresponding periods 2015-2019. There was an increased training injury incidence and injury burden immediately during the lockdown in 2020, and they remained elevated also following the restart, being higher in 2020 compared with 2015-2019, respectively. The injury characteristics during the first months of the new 2020/21 season (August/September-December) were similar between the five teams that cancelled their 2019/20 season in March 2020 and the 14 teams that restarted their season in May/June 2020.

CONCLUSIONS

There was no increased match injury incidence or injury burden following the COVID-19 lockdown and restart of the football season in 2020, but training injury incidence and injury burden were elevated and higher than in 2015-2019.

Association between SARS-COV-2 infection and muscle strain injury occurrence in elite male football players: a prospective study of 29 weeks including three teams from the Belgian professional football league

OBJECTIVES

The aim of this study was to investigate the association between SARS-CoV-2 infection and muscle strain injury in elite athletes.

METHODS

A prospective cohort study in three Belgian professional male football teams was performed during the first half of the 2020-2021 season (June 2020-January 2021). Injury data were collected using established surveillance methods. Assessment of SARS-CoV-2 infection was performed by a PCR test before each official game.

RESULTS

Of the 84 included participants, 22 were infected with SARS-CoV-2 and 14 players developed a muscle strain during the follow-up period. Cox's proportional hazards regression analyses demonstrated a significant association between SARS-CoV-2 infection and the development of muscle strain (HR 5.1; 95% CI 1.1 to 23.1; p=0.037), indicating an increased risk of developing muscle strains following SARS-CoV-2 infection. All athletes who sustained a muscle strain after infection were injured within the first month (15.71±11.74 days) after sports resumption and completed a longer time in quarantine (14.57±6.50 days) compared with the infected players who did not develop a muscle strain (11.18±5.25 days).

CONCLUSION

This study reported a five times higher risk of developing a muscle strain after a SARS-CoV-2 infection in elite male football players. Although this association should be examined further, it is possible that short-term detraining effects due to quarantine, and potentially pathological effects of the SARS-CoV-2 infection are associated with a higher risk of muscle strain injury.