For elite sportsmen and women across the world the COVID-19 pandemic has imposed huge challenges as they have had to forego competition and strive to keep themselves mentally and physically prepared for the day when their events are restored.
But there is a significant sub-set within that elite group for whom the pandemic has represented an even more profound challenge as they have been actively engaged - as doctors, nurses, carers - in helping those stricken by coronavirus.
One of those who has played a hugely significant part over the course of the last year is former United States judoka Christina Yannetsos, a silver medallist at the 2003 Pan American Games, who is now an emergency room physician and assistant professor of emergency medicine for the University of Colorado's School of Medicine in Denver.
Despite all the precautions taken and protective personal equipment (PPE) worn, Yannetsos, who is 37, herself fell ill with COVID-19 during the second wave of infections in the United States in November, and while she told insidethegames she had had "moderate symptoms", Yannetsos added that she had been adversely affected in terms of her health for several months.
She is now back at work.
Yannetsos is a shining example of the selflessness with which so many elite athletes have addressed themselves to the current health crisis.
She began her medical training in earnest soon after the Athens 2004 Olympics, for which Yannetsos had qualified to represent the US, only to suffer a shoulder injury that prevented her taking part, although she did travel to Athens as an alternate and training partner.
While her medical career is her top priority Yannetsos has maintained connection to her sport, having been appointed in 2019 as head team physician for USA Judo, and another Olympic appearance now hangs on her horizon.
In an interview last year with Team USA, Yannetsos said: "In being an emergency physician, you go through medical school, you go through years of training and nothing prepares you for what you see and face every day in the emergency department with COVID.
"It’s as if everything that we’ve learned has kind of been thrown out in the woods so to speak. We learn and train that when someone is in distress, run in and help save them and now we are focusing on making sure everyone is protected.
"Make sure you have your protective gear on gowns, protective masks and face shields. The donning and doffing of putting on and taking off of this gear is quite laborious to be honest; it takes time.
"There are real exposure risks, which is why protective equipment is so important to us and why we protect ourselves."
Asked if she had since become more able to deal with that conundrum, Yannetsos told insidethegames: "No, I don’t think I have really come to terms with it. I think once you get into medicine and other first-responder professions, your first instinct is that you want to help as safely as possible, however when you see a life in danger and you have the ability to help, and are trained to help, you still run to help.
"Being vaccinated and making sure standard precautions are taken with each patient helps facilitate my confidence in making sure I am protecting myself as well."
The vaccination, however, did not come in time to prevent her getting the virus herself.
"I did get COVID in November during our second peak, in which I had moderate symptoms, but felt like I was letting my team down because I could not fight beside them while I was sick," Yannetsos said.
"I’m OK now. But after November I had some decreased exercise tolerance for a few months and got short of breath with any exertional activities."
Reflecting upon the times of peak stress in her professional capacity, Yannetsos said: "I think the main difficulties were working within finite resources and focusing on the safety of myself and staff.
"There were days that the hospital had stopped elective procedures, hospitals in the city were on divert [no longer accepting patients by ambulance], and we were doing everything we could to make space for people and make sure we had resources to help everyone.
"Meanwhile, doing my best to keep my family safe and healthy. My mother has cancer, so it was difficult not seeing her and my dad and brother, and I was trying to make sure I stayed healthy when I came home to my husband to not get him sick - so it was a case of disrobing in the garage and mustering the energy to shower once you are exhausted from working so hard every day."
2003 PanAmerican Games Dominican Republic, -70kg USA (me) vs Ecuador. I ended up with a Silver Medal at this event and this helped solidify @USAJudo -70kg spot for the 2004 Olympics pic.twitter.com/tZbTuXNhUj— Christina Yannetsos, MD (@JudoninaMD) April 4, 2021
Yannetsos is aware of a number of elite athletes who are doing their bit in the battle against COVID-19.
"I have several athletes who work as nurses and are training for the Olympics with USA Judo," she said. "Chantal Wright being one of them."
Wright, who has represented the United States since 2014 having previously competed for Switzerland and Britain, works in an intensive care unit.
In March 2020, Yannetsos worked with the American College of Emergency Physicians to speak to Senators and Representatives in Washington DC to help obtain PPE and discussed the challenges faced by American physicians on the front lines.
A month later Yannetsos took delivery of 300 hospital-grade masks that had been sourced and sent to her by China's Brining 2008 Olympic gold medallist and London 2012 bronze medallist judoka Tong Wen, following discussions with her long-time friend Keith Bryant, the USA Judo chief executive.
The items were swiftly distributed to Yannetsos' team mates and fellow frontline workers in the battle against COVID-19.
Yannetsos said she was "excited" to hear that another former elite sportswoman, Canada’s four-time Olympic ice hockey gold medallist Hayley Wickenheiser, was following her own professional path in training to become an emergency medicine physician.
Today I’m here with the amazing @wick_22 and the men and women of the @conquercovid19 team for their PPE drive. Incredible leadership. Incredible spirit. I am honoured to see them in action. We are #StrongerTogether. If you have PPE please donate. https://t.co/JOT7pYO9CW pic.twitter.com/txJVG9Nsnh— Doug Ford (@fordnation) April 11, 2020
Wickenheiser witnessed at first-hand the trauma suffered by COVID-19 sufferers early in the pandemic as she was involved in emergency medicine during training as part of her course at the University of Calgary's medical school.
Soon afterwards she began leading from the front in another area as, along with her friend Ryan Reynolds, the Canadian-American film actor and producer, Wickenheiser spearheaded the Conquer COVID-19 appeal to collect and transport PPE to frontline emergency medical workers across Canada.
Working in partnership with a group of volunteers, and with input from numerous local and national businesses, Wickenheiser and Reynolds set up a regular opportunity for the public to donate equipment, or cash, in a safe and socially-distanced manner in Toronto.
Wickenheiser will qualify as a doctor on May 12 and has applied to work in the area of family emergency medicine.
She offers a fairly grim analysis of the COVID-19 situation as she encounters it on a daily basis.
"I think I am on the front lines. I’m in the surgery right now, I’m in the operating theatre every day, and obviously people are seeing patients that are intubated in hospitals," she told insidethegames.
"Things continue on with these variants and extreme measures, and I think we are still a ways away from being able to say we are out of this pandemic and moving forward.
"I think the situation is as bad as it has been since the start, and with the third wave and the variants I think we are in this for the long haul, so it’s just important to stay vigilant,.
"And as people get vaccinated I think we are just going to be dealing with variants of this virus and hopefully it will become like the flu over time where we can keep it from being a lethal disease.
"So right now I think it is situation critical in Canada and I think many parts of the world. We are facing lockdowns in many parts of the country. I'm in Alberta, but Ontario has just gone into full lockdown and we will be right behind that.
Also working on the COVID-19 front lines in Canada is Joannie Rochette, Olympic figure skating bronze medallist at the Vancouver 2010 Winter Games, who works as an anaesthesiologist in Montreal.
Meanwhile 30-year-old medical school graduate Laurent Duvernay-Tardif, who was with the Kansas City Chiefs when they won the Super Bowl in February 2020, opted out of the following season because he wanted to help combat the virus outbreak and returned to his own province of Quebec to work at CHSLD Gertrude-Lafrance, a long-term care facility in Saint-Jean-sur-Richelieu.
Paula Pareto, who at the Rio 2016 Games became the first woman to win an individual Olympic judo title for Argentina, is currently balancing efforts to reach a fourth consecutive Olympics with a full-time role as a doctor in a Buenos Aires hospital.
The 35-year-old national treasure - who was the Argentinian flagbearer at the Olympic Closing Ceremony in 2016 - frequently encounters COVID-19 patients in her job as a traumatologist, dealing in wounds and injuries caused by accidents or violence.
"In the hospital the cases are increasing, but the health system hasn’t collapsed, which is the fear everyone has," she told the Olympic Channel. "Even if we work in traumatology we give a hand to the other doctors of the medical team.
"Obviously we are also attending the patients who come to our department. We had some patients in traumatology also affected by coronavirus.
"So we had to be extra careful in order to help them and ourselves, by preventing the disease from spreading and by treating each patient in the best possible way.
"I think the most important thing is to know what is good and what is wrong. We all know how the virus spreads and how to prevent it. Each of us needs to take responsibility. It’s not just about mandatory measures.
"We have to take care of ourselves and others to face this virus. I think it’s the only way."
Movement is medicine. This is just ridiculous. https://t.co/X7ehOJhR5h— Hayley Wickenheiser (@wick_22) April 17, 2021
Known as La Peque - The Small One - as she is just 1.48 metres tall, Pareto competes in the under-48 kilograms extra-lightweight category, and before winning her Olympic gold she had earned bronze from Beijing 2008 as well as the 2015 world title.
Pareto is working towards her fourth consecutive Olympic appearance, thanks partly to a series of innovative home-based strength and conditioning exercises, and is riding high in the world rankings that are due to be finalised on June 28.
Two-time 400 metres hurdles world champion Jana Pittman qualified as a doctor shortly before the arrival of the COVID-19 pandemic.
The only Australian woman to appear in both Summer and Winter Olympic Games - she competed in bobsleigh at Sochi 2014 - Pittman had her first day on shift in January 2020.
Pittman gave birth to her fourth child at the end of 2020 and is now studying for a PhD in medicine.
Former Dutch hockey goalkeeper Joyce Sombroek, a gold medallist at the London 2012 Olympics and silver medallist at the Rio 2016 Games, has been helping with efforts to combat COVID in Amsterdam.
Having retired after Rio 2016 due to recurring hip problems, Sombroek completed her medical studies at Amsterdam's Vrjie Universiteit and worked in departments including emergency rooms before beginning training as a general practitioner (GP).
Sambroek recently posted on social media: "My first year of GP training is over. A year that I will not soon forget, not only because of covid-19 but especially also because of my nice colleagues and patients!"
Jo Brigden-Jones, who represented Australia in kayaking at London 2012 and learned shortly before the pandemic that she had been selected to go to the Tokyo 2020 Olympics, is working as a paramedic for New South Wales Ambulances.
Brigden-Jones, who won bronze at the 2011 International Canoe Federation World Championships in the K2 200m event before competing in the K4 500m at London 2012 , started working full-time in her "dream career" after being controversially left out of the Rio 2016 team.
The 32-year-old from Mona Vale, who is also a member of the Manly Surf Life Saving Club, planned to retire from the sport, but was drawn back into it in the years following Rio.
When the COVID-19 pandemic occurred, Brigden-Jones told ABC Grandstand that she had been instructed to leave Sydney for the Gold Coast for intensive training ahead of Tokyo 2020.
When the Games were postponed, however, that move was put on hold and she returned to work full-time, with much of it spent in transporting coronavirus victims to hospital.
She has since resumed preparations on the water for the upcoming challenge of her second Olympics.
For the two-time Scottish curling champion Vicky Wright the coronavirus pandemic had a similar impact.
She had been due to compete in Canada at the Women's World Curling Championship in March 2020, but the event was postponed two days before it was scheduled to start - by which time the curlers had already arrived in venue Prince George.
Wright, who now plays lead in Sochi 2014 bronze medallist Eve Muirhead's rink, returned home and went back to nursing. The 27-year-old had switched to curling full-time in July 2019 in order to focus on Beijing 2022, but she was able to continue working occasionally at the Forth Valley Royal Hospital near Falkirk.
She told British Curling's website: "Both the NHS and British Curling enabled me to do one shift a week throughout this season. It was something I really enjoyed and I didn’t want to lose my skills and it was good to have something else other than just curling, it really kept me grounded.
"Being a nurse has always given me a good perspective on life and kept my focus on what is important."
Britain’s two-time Paralympic table tennis player Kim Daybell has joined the fight against COVID-19 at the Whittington Hospital in north London, where he works full-time as a junior doctor.
The 27-year-old was born with Poland's syndrome which means he has next to no chest muscles on one side of his body, but that has not stopped him pursuing dual careers in table tennis and medicine, with his plans to train full-time for a third Paralympics in Tokyo having been put on hold.
Daybell told British Para Table Tennis: "I want to try and help as best I can and it is quite nice to be able to do that. One of the things that people seem to be struggling with is that feeling of powerlessness where they can’t do anything. I’m lucky to have the skill-set to help fight what is going on and that is a positive that I’m taking.
"Obviously table tennis has completely taken a back seat now and sport has as well but it will always be there for me so I’ll keep it in mind for when this blows over."
Rachel Buehler Van Hollebeke, a member of the United States women’s football team that won gold at the Beijing 2008 and London 2012 Olympics, is a medical doctor who has been on the frontline throughout the pandemic.
Another prominent women's footballer, Atletico Madrid vice-captain Silvia Meseguer, was one of those who volunteered to help in the field hospital for COVID-19 sufferers set up in the IFEMA exhibition complex in Spain's capital.
Meseguer retired from international football in 2019 to focus on completing her studies at medical school.
She told Atletico Madrid's official website: "Seeing the situation we are experiencing, I think anything we can contribute right now is important. I still don't have a medical degree because I have yet to finish my final project, but if they need help from students, of course I will."
Singapore’s 110m hurdles record holder Ang Chen Xiang has been dealing regularly with COVID-19 patients as a medical officer at Khoo Teck Puat Hospital's emergency department.
The 25-year-old told the Straits Times: "It's difficult to convey emotion and empathy while wearing the full PPE and I try to smile through my eyes, but they are really small, so they're closed when I'm smiling!"
He said even reassuring words to patients can be muffled under the mask, adding: "I give them a timeline and course of action to expect and assure them that as a team, we'll take care of them."
The national hurdler had requested to work in the emergency department as he "wanted to help in the fight against COVID-19", working shifts doing swab tests and caring for coronavirus and non-virus patients.
Ang, who competed at the South East Asian Games from 2015 to 2019 and holds the national 110m hurdles record of 14.25sec, tries to squeeze in a daily training session with his younger brother and coach Ding Hui - safe distancing measures included - and acknowledged that wearing PPE for up to 10 hours daily while treating patients could be draining.
He works out in his home gym or practises with plastic hurdles on the roads near his home.
Following the postponement of the Tokyo 2020 Games, Australian hockey goalkeeper Rachael Lynch resumed full-time working as a nurse.
The 34-year-old Rio 2016 Olympian had been working as a nurse one day a week for more than 10 years in a career that has seen her earn gold medals from the Delhi 2010 and Glasgow 2014 Commonwealth Games as well as a silver medal from the 2014 World Cup
Shortly after the decision to try and stage the Tokyo 2020 Games in 2021, Lynch told the Sydney Morning Herald: "I had hoped that it would get postponed.
"I'd been getting quite frustrated in the lead up to that, I knew that I wanted to be at the hospital and working and also distancing myself from the other hockey girls in our programme."
At the time she was working at Perth's neuro-rehab ward but with more time available was applying to be part of the COVID-19 Assessment Centre.
With case rates still high in many parts of the world, these elite athletes are set to continue in the fight against COVID-19.