Martin Schwellnus

University of Pretoria | UP · Sport, Exercise Medicine and Lifestyle Institute (SEMLI)

Objective To determine the incidence of acute respiratory illness (ARill) in athletes and by method of diagnosis, anatomical classification, ages, levels of performance and seasons. Design Systematic review and meta-analysis. Data sources Electronic databases: PubMed-Medline, EbscoHost and Web of Science. Eligibility criteria Original research a...

Objective To review risk factors associated with acute respiratory illness (ARill) in athletes, including non-infectious ARill and suspected or confirmed acute respiratory infections (ARinf). Design Systematic review. Data sources Electronic databases: PubMed-Medline, EbscoHost and Web of Science. Eligibility criteria Original research articles...

Acute respiratory illness (ARill) is common and threatens the health of athletes. ARill in athletes forms a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. The aim of this consensus is to provide the SEM clinician with an overview and practical clinical approach to non-infective ARill in athletes. The Internationa...

Acute illnesses affecting the respiratory tract are common and form a significant component of the work of Sport and Exercise Medicine (SEM) clinicians. Acute respiratory illness (ARill) can broadly be classified as non-infective ARill and acute respiratory infections (ARinf). The aim of this consensus is to provide the SEM clinician with an overvi...

Purpose: To determine factors predictive of prolonged return to training (RTT) in athletes with recent SARS-CoV-2 infection. Methods: Cross-sectional descriptive study. Athletes not vaccinated against COVID-19 (n = 207) with confirmed SARS-CoV-2 infection (predominantly ancestral virus and beta-variant) completed an online survey detailing the f...

Background Information on acute traumatic cycling injuries (ATCIs) in the 12 months prior to entry in a cycling race and the predisposing factors have not been well-researched. Objective Determine factors associated with a history of ATCIs sustained in the previous 12 months by race entrants of a 109 km cycling race. Methods Descriptive, cross-se...

Objective: The aim of this study was to determine the incidence and nature (severity and type by organ system and specific diagnosis) of all medical encounters (MEs), including serious/life-threatening MEs (SLMEs) during a South African road marathon. Methods: This descriptive study was a retrospective analysis of data collected over 6 years at...

Objective To determine if any gradual onset running-related injury (GORRI) was associated with any allergies, multiple allergies (allergies to animals, plants, medication), and allergy medication use. Design Cross-sectional descriptive study. Setting Two Oceans Marathons (56 km, 21.1 km), South Africa. Participants A total of 76 654 race entrant...

This paper provides an overview of the HEAT (Healthy Environments for AthleTes) project, which aims to understand the impact of environmental conditions on athlete health and performance during major sporting events such as long-distance running, cycling, and triathlons. In collaboration with the SAFER (Strategies to Reduce Adverse Medical Events F...

Background: The prevalence of a history of exercise-associated muscle cramping (hEAMC) among ultramarathon runners is high. While the Comrades is one of the most popular mass community-based participation ultramarathons (90km) globally, research on the epidemiology, clinical characteristics, and risk factors of entrants' lifetime hEAMC are scarce....

Background Gradual‐onset Achilles tendon injuries (GoATIs) in runners are common. Data show that chronic diseases are associated with GoATI. Objective To determine risk factors associated with a history of GoATIs among long‐distance runners (21.1 and 56 km) entering a mass community‐based running event. Methods Online pre‐race medical screening q...

Background The International Olympic Committee (IOC) Medical and Scientific Commission has supported collating and sharing evidence globally by developing sports medicine consensus statements (‘Statements’'). Publishing the Statements requires substantial resources that must be balanced by use and impact on policy and practice. This study aimed to...

Background: Despite the numerous health benefits of distance running, it is also associated with the development of 'gradual onset running-related injuries' (GORRIs) one of which is Iliotibial Band Syndrome (ITBS). Novel risk factors associated with a history of ITBS (hITBS) have not been described in a large cohort of distance runners. Objective...

Background The severity of SARS-CoV-2 infection [days to return to sport (RTS)] in athletes has been associated with the total number of acute symptoms. Data on the association between acute symptoms and demographics, sport participation, co-morbidities/allergies and organ involvement are however lacking. Objective To explore if the number of acut...

Background Patellofemoral pain (PFP) is common in cyclists, but factors associated with PFP in cyclists have not been well studied. Objectives The study aimed to identify factors (lower limb functional and frontal plane knee kinematic variables) associated with PFP in cyclists. Design Matched case-control. Setting SEMLI Biomechanics laboratory,...

Background Acute respiratory infections (ARinf) are the most common medical reason for athletes to miss training or competition. The influence that different pathogens have on the time to return-to-training (RTT) and return-to-full performance (RTFP) remains unknown. Objective To determine whether the time to RTT and RTFP following an ARinf differ...

Background There is a high incidence of medical encounters (MEs) and serious/life-threatening MEs in marathon road running races but injury and illness risk factors associated with MEs in these events have not been well investigated and will assist with injury and illness prevention. Objective To determine the independent risk factors that are ass...

Background The prevalence of exercise-associated muscle cramping (EAMC) among ultramarathon runners is high. While the Comrades is one of the most popular mass community-based participation ultramarathons (90km) globally, research on the risk factors of entrants’ lifetime history (hEAMC) is scarce. Objective Investigate selected risk factors of hE...

Background Running and cycling are two of the most popular forms of physical exercise worldwide, with increased participation by older and female athletes. Gradual onset injuries (GOIs) are common in these two sports, requiring individually targeted injury prevention strategies. Objective To determine differences in the period prevalence (12 month...

The incidence of acute respiratory infections (ARinf), including SARS-CoV-2, in unvaccinated student rugby players during phases from complete lockdown during the COVID-19 pandemic to returning to competition is unknown. The aim of the study was to determine the incidence of ARinf (including SARS-CoV-2) during non-contact and contact phases during...

Objective To describe the epidemiology of injuries and illnesses sustained during the Beijing 2022 Paralympic Winter Games, organised in a closed-loop environment to adhere with COVID-19 restrictions. Methods Injuries and illnesses from all teams were recorded on a daily basis by team medical staff on a web-based form and by local organising commi...

Objectives The relationship between sport-related injuries and Para athlete impairment type has not yet been comprehensively studied. This study aimed to describe injury incidence according to athlete impairment type during the London 2012 and Rio 2016 Summer Paralympic Games, by sex, age, Games period, chronicity and anatomical area. Methods A co...

Purpose The aim of the study was to identify factors associated with prolonged time to return to full performance (RTFP) in athletes with recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Methods Prospective cohort study with cross sectional analysis. A total of 84 athletes with confirmed SARS-CoV-2 infection assessed...

Background: In low-to-middle income countries (LMICs), there is a growing burden of non-communicable diseases (NCDs) placing strain on the facilities and human resources of healthcare systems. Prevention strategies that include lifestyle behavior counseling have become increasingly important. We propose a potential solution to the growing burden of...

Objective To determine if two pre‐race screening tools (abbreviated tool of two open‐ended pre‐race medical screening questions [ABBR] vs. a full pre‐race medical screening tool [FULL]) identify running race entrants at higher risk for medical encounters (MEs) on race day. Methods 5771 consenting race entrants completed both an ABBR and a FULL pre...

Objective: Patellofemoral pain syndrome (PFPS) is a common running-related injury. Independent risk factors associated with PFPS have not been described in a large cohort of distance runners. Design: Descriptive, cross-sectional study. Setting: 21.1 and 56 km Two Oceans Marathon races (2012-2015). Participants: 60 997 race entrants. Assessm...

Context: SARS-CoV-2 infection can affect the exercise response in athletes. Factors associated with the exercise response have not been reported. Objective: This study aimed to: 1) describe heart rate (HR), systolic blood pressure (SBP), and rating of perceived exertion (RPE) responses to exercise in athletes with recent SARS-CoV-2 infection, an...

BACKGROUND: The prevalence of a history of exercise-associated muscle cramps (hEAMC) among ultramarathon runners is high. While the Comrades is one of the most popular community-based mass participation ultramarathons (90km) globally, research on the epidemiology and clinical characteristics of entrants' lifetime hEAMC is scarce. PURPOSE: To descri...

Background: There is limited evidence available on contributing factors for gradual onset running-related injuries (GORRIs) in ultramarathon runners. The aim was to determine if selected risk factors were associated with a history of GORRIs in 90-km ultramarathon race entrants. Methods: Descriptive cross-sectional study. GORRI and medical data u...

Background: Gastrointestinal tract illness (GITill) in rugby players is underreported. The incidence, severity (% time loss illness, days lost per illness) and burden of GITill with/without systemic symptoms and signs in professional South African male rugby players during the Super Rugby tournament (2013-2017) are reported. Methods: Team physic...

Background Research evidence is commonly compiled into expert-agreed consensus statements or guidelines, with an increasing trend towards their publication in peer-reviewed journals. Prominent among these has been the publication of several International Olympic Committee (IOC) tatements to help inform sport and exercise medicine (SEM) practice. Th...

Objectives Research evidence is commonly compiled into expert-informed consensus guidelines intended to consolidate and distribute sports medicine knowledge. Between 2003 and 2018, 27 International Olympic Committee (IOC) consensus statements were produced. This study explored the policy and practice impact of the IOC Statements on athlete health a...

Objectives: Currently there are five international screening tools that are recommended to identify individuals who require pre-exercise medical clearance to reduce the risk of medical encounters during exercise. Therefore, the aim was to determine the percentage of race entrants who are advised to obtain pre-exercise medical clearance and the obs...

Objectives To compare the performance of various diagnostic bronchoprovocation tests (BPT) in the assessment of lower airway dysfunction (LAD) in athletes and inform best clinical practice. Design Systematic review with sensitivity and specificity meta-analyses. Data sources PubMed, EBSCOhost and Web of Science (1 January 1990–31 December 2021)....

Objective: To determine independent risk factors associated with a history of exercise-associated muscle cramps (hEAMCs) in distance runner race entrants in a community-based mass participation event. Design: Cross-sectional study. Setting: 2012 to 2015, Two Oceans marathon races (21.1 and 56 km), South Africa. Participants: Seventy six thou...

Objective To describe the incidence and burden of illness at the Tokyo 2020 Paralympic Games, which was organised with strict COVID-19 countermeasures. Methods Daily illnesses were recorded via the web-based injury and illness surveillance system (teams with their own medical staff; n=81), and local polyclinic services (teams without their own med...

Objective To describe the epidemiology of injuries at the Tokyo 2020 Paralympic Games, including injuries sustained in the new sports of badminton and taekwondo. Methods Injury data were obtained daily via the established web-based injury and illness surveillance system (WEB-IISS; 81 countries, 3836 athletes) and local organising committee medical...

Objective: Patellofemoral pain (PFP) is a common cycling-related injury, and independent factors need to be identified to enable effective injury prevention strategies. We aim to determine factors associated with PFP in cyclists entering mass community-based events. Design: Cross-sectional study. Setting: 2016-2020 Cape Town Cycle Tour. Parti...

The paper introduces the Healthy Environments for Athletes field campaign to measure environmental conditions (heat stress and allergenic agents) associated with endurance events.

Objective Gradual onset injuries (GOIs) in recreational cyclists are common but not well described. The aim of this study is to describe the clinical characteristics of GOIs (main anatomical regions, specific anatomical sites, specific GOIs, tissue type, severity of GOIs, and treatment modalities) of GOIs among entrants participating in a community...

Exertional Syncope In A Athlete With Recent SARS-Cov-2 Infection - Endurance Sport: Author Block: Marcel Jooste, Martin Schwellnus, FACSM. University of Pretoria, Pretoria, South Africa. HISTORY: A 53-year-old competitive masters endurance athlete presented for return to sport clearance 20 days following SARS-CoV-2 infection. During acute phase,...

Objective To describe the incidence and transmission of SARS-CoV-2 infections in South African professional rugby union players in different phases of return-to-competition during a pandemic. Design Prospective cohort study. Methods Players reported their history of SARS-CoV-2 infection before / during a national competition, using an online ques...

Acute respiratory infections (ARinf) are common in athletes, but their effects on exercise and sports performance remain unclear. This systematic review aimed to determine the acute (short‐term) and longer‐term effects of ARinf, including SARS‐CoV‐2 infection, on exercise and sports performance outcomes in athletes. Data sources searched included P...

Background There are limited data on the medical encounters (MEs) occurring during mass community-based running events of shorter distances (10-21.1 km). The aim of this study was to determine the incidence and nature of MEs during the largest mass participation running event in the Netherlands. Hypothesis We hypothesize that the incidence and nat...

Background: Exercise associated collapse (EAC) is a common medical encounter at distance running events. Risk factors associated with EAC are not well documented. The objective is to determine the overall incidence of EAC and identify risk factors associated with EAC in 21.1km and 56km runners. Methods: A cross-sectional analysis of 153208 race...

Objectives The aim of this study is to review the evidence available suggesting that environmental conditions represent a risk factor associated with non-infective acute respiratory illness in athletes. Design Systematic review. Methods PubMed, EBSCOhost and Web of Science (1st January 1990–31 July 2020) were searched systematically using keyword...

Exercise-induced laryngeal obstruction (EILO) is caused by paradoxical inspiratory adduction of laryngeal structures during exercise. EILO is an important cause of upper airway dysfunction in young individuals and athletes, can impair exercise performance and mimic lower airway dysfunction, such as asthma and/or exercise-induced bronchoconstriction...

Background Medial Tibial Stress Syndrome (MTSS) is one of the most common causes of exercise-associated lower leg pain in distance runners. Aim To identify risk factors predictive of a history of MTSS in distance runners entering the Two Oceans Marathon races (21.1km and 56km). Design Cross-sectional study Setting 2012 to 2015 Two Oceans Maratho...

Objective: To determine if scientifically based social network (Facebook) lifestyle interventions reduce 10-year cardiovascular disease (CVD) risk. Methods: Financial sector employees (n = 300) were equally randomly assigned: Facebook plus Health Professionals (FB+HP), Facebook (FB), or control (C). We report changes in 10-year Framingham risk s...

Objective To determine the days until return to sport (RTS) after acute respiratory illness (ARill), frequency of time loss after ARill resulting in >1 day lost from training/competition, and symptom duration (days) of ARill in athletes. Design Systematic review and meta-analysis. Data sources PubMed, EBSCOhost, Web of Science, January 1990–July...

Objective: To determine whether the lifetime prevalence and clinical characteristics of exercise-associated muscle cramping (EAMC) differ between runners entering a 21.1- versus 56-km road race. Design: Cross-sectional study. Setting: The 2012 to 2015 Two Oceans Marathon races (21.1 and 56 km), South Africa. Participants: Participants were c...

Objectives To determine the prevalence of self-reported pre-race chronic medical conditions and allergies in ultramarathon race entrants and to explore if these are associated with an increased risk of race-day medical encounters (MEs). Methods Data from two voluntary open-ended pre-race medical screening questions (Q1 – history of allergies; Q2 -...

Objective There are limited data on factors that predict an increased risk of multiple injuries among distance runners. The objective of this study is to determine risk factors that are predictive of individual runners with a high annual multiple injury risk (MIR). Methods A retrospective, cross-sectional study at 4 annual (2012–2015) Two Oceans 2...

Background Race starting time is often staggered over several hours in large mass-participation endurance sports events. Athlete exposure to environmental conditions changes as wet-bulb-globe-temperature (WBGT) changes during race day. Slower participants may be exposed to changing environmental conditions for a longer duration. In most studies env...

Background The IOC Sports Medical and Scientific Commission has supported the development and dissemination of sports medicine consensus statements for athlete health. Evidence on the relevance and dissemination of these statements is important for the development of future statements. Objective The objective of this project was to investigate the...

Background The International Olympic Committee (IOC) Medical and Scientific Commission has a goal to provide guidance on athlete health for sports organisations. One strategy to meet this goal has been the development and publication of sports medicine consensus statements. It is currently unknown if there has been use of the consensus statements o...

Background There is a high incidence of medical encounters (MEs) in ultramarathon road running races but risk factors associated with MEs in events have not been well investigated. Objective To determine the independent risk factors for all medical encounters in a 90km ultramarathon running race. Design Retrospective clinical audit, cross-section...

Background Risk factors associated with overuse injuries in cyclists (OICs) in recreational cyclists have not been well-studied. Objective To determine risk factors associated with OICs in recreational cyclists participating in a mass community-based cycling event. Design Cross-sectional study. Setting Cape Town Cycle Tour (CTCT) 2016. Patients...

Background One of the goals of the International Olympic Committee (IOC) Medical and Scientific Commission is to provide guidance in relation to injury prevention and the protection of athlete health. One way of meeting this goal is the development and dissemination of sports medicine consensus statements. It is not known if, or how, these consensu...

Background There have been 27 consensus statements published under the International Olympic Committee (IOC) Medical and Scientific Commission with a goal of contributing to the mission of injury prevention and protection of athlete health. The success of these statements in achieving this goal has not been evaluated. Knowledge management (KM) cons...

Background Injury-related medical encounters (injMEs) are common in mass community-based participation cycling events, but there are limited data on the risk factors associated with injuries in endurance cycling events. Objective To determine the risk factors associated with injMEs in a mass community-based endurance cycling event. Design Retrosp...

Background Netball is a fast action game and there is growing interest in the sport. The Netball World Cup (NWC) is an international netball world championship, contested every four years, with 16 teams qualifying by ranking and play-offs. Research on netball injuries is however limited. Objective To determine the incidence and severity of injurie...

Background The IOC Medical and Scientific commission’s mission is to provide a guiding reference for sports organisations on issues relating to the protection of the health of athletes. One strategy to achieve this mission is through supporting the development of consensus statements. Objective This study investigates the relevance and disseminati...

Background Pre-race medical screening at endurance events has recently been suggested, but there are limited data on the use of pre-race questionnaire data to predict adverse events (defined as medical encounters or not finishing a race). Objective To determine if risk factors, that are identified from a pre-race medical screening questionnaire, a...