A woman cycles past a homeless tent at Muscle Beach, as the coronavirus disease (COVID-19) disease pandemic continues, on Venice Beach in Los Angeles, California, U.S., April 13, 2021. REUTERS/Lucy Nicholson

A surfer walks past Muscle Beach to the ocean, as the coronavirus disease (COVID-19) disease pandemic continues, on Venice Beach in Los Angeles, California, U.S., April 13, 2021. REUTERS/Lucy Nicholson

Zhao Shuyuan, 61, shows his muscles at a gym which has been turned from a bicycle shed inside a residential compound in the southwest of Beijing, China April 8, 2021. Picture taken April 8, 2021. REUTERS/Tingshu Wang

Xu Wei, a 63-year-old former factory worker and the current gym manager, show his muscles at the gym which has been turned from a bicycle shed inside a residential compound in the southwest of Beijing, China April 8, 2021. Picture taken April 8, 2021. REUTERS/Tingshu Wang

Long COVID sufferer Beatriz Perez, a 51-year-old computer engineer, poses for a photograph taken through blue plastic, in Fuenlabrada, Spain, March 4, 2021. The photograph was taken through blue plastic to visualise the effects of long COVID. Perez used to go trekking on weekends, but now is rarely able to complete her personal challenge of walking all the way down the stairs from her eighth-floor apartment, not to mention up. "One day I tried to at least go down the stairs and I don't even think I made it two floors down, I was in so much pain. I felt so disappointed. Am I ever going to be able to live a normal life again?" she said. Permanent fatigue, muscle and joint pain and forgetfulness have kept her off work for a year, and she says "the worst thing is living with the uncertainty" of not knowing when or if she will recover. Perez leads a daily mindfulness online class with other people who suffer from long COVID. "If it were not for meditation I might have already been put on antidepressants." REUTERS/Susana Vera SEARCH "SPAIN LONGCOVID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

A thermometer belonging to long COVID sufferer Amaia Artica, 42, is seen photographed through blue plastic, in Pamplona, Spain, March 16, 2021. The photograph was taken through blue plastic to visualise the effects of long COVID. Permanent fatigue, daily fever, muscle and joint pain, insomnia and constant mental lapses have kept Artica from doing the job she loves at a nursery school since she got infected with coronavirus during the first wave of the disease. Her brain fogginess is so acute that there are days she finds herself staring at a blank wall, feeling "out of it". Loss for words, inability to remember how to do simple tasks and overall forgetfulness have become part of her life. Artica suffers from daily low-grade fever. "My family doctor has been very supportive of me throughout this ordeal, but not all doctors have been that understanding. A specialist doctor told me to stop taking my temperature, that if I didn't pay attention to it, it would go away because it was all in my head." REUTERS/Susana Vera SEARCH "SPAIN LONGCOVID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

Long COVID sufferer Amaia Artica, a 42-year-old nursery school worker, poses for a photograph taken through blue plastic, in Pamplona, Spain, March 16, 2021. The photograph was taken through blue plastic to visualise the effects of long COVID. Permanent fatigue, daily fever, muscle and joint pain, insomnia and constant mental lapses have kept Artica from doing the job she loves at a nursery school since she got infected with coronavirus during the first wave of the disease. Her brain fogginess is so acute that there are days she finds herself staring at a blank wall, feeling "out of it". Loss for words, inability to remember how to do simple tasks and overall forgetfulness have become part of her life. Artica suffers from daily low-grade fever. "My family doctor has been very supportive of me throughout this ordeal, but not all doctors have been that understanding. A specialist doctor told me to stop taking my temperature, that if I didn't pay attention to it, it would go away because it was all in my head." REUTERS/Susana Vera SEARCH "SPAIN LONGCOVID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

The staircase leading to the flat of long COVID sufferer Beatriz Perez, 51-year-old computer engineer, is seen photographed through blue plastic in Fuenlabrada, Spain, March 4, 2021. The photograph was taken through blue plastic to visualise the effects of long COVID. Perez used to go trekking on weekends, but now is rarely able to complete her personal challenge of walking all the way down the stairs from her eighth-floor apartment, not to mention up. "One day I tried to at least go down the stairs and I don't even think I made it two floors down, I was in so much pain. I felt so disappointed. Am I ever going to be able to live a normal life again?" she said. Permanent fatigue, muscle and joint pain and forgetfulness have kept her off work for a year, and she says "the worst thing is living with the uncertainty" of not knowing when or if she will recover. Perez leads a daily mindfulness online class with other people who suffer from long COVID. "If it were not for meditation I might have already been put on antidepressants." REUTERS/Susana Vera SEARCH "SPAIN LONGCOVID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

A combination picture shows long COVID sufferer Amaia Artica, 42, posing for a photograph taken through blue plastic, and a thermometer belonging to Artica photographed through blue plastic, in Pamplona, Spain, March 16, 2021. The photographs were taken through blue plastic to visualise the effects of long COVID. Permanent fatigue, daily fever, muscle and joint pain, insomnia and constant mental lapses have kept Artica from doing the job she loves at a nursery school since she got infected with coronavirus during the first wave of the disease. Her brain fogginess is so acute that there are days she finds herself staring at a blank wall, feeling "out of it". Loss for words, inability to remember how to do simple tasks and overall forgetfulness have become part of her life. Artica suffers from daily low-grade fever. "My family doctor has been very supportive of me throughout this ordeal, but not all doctors have been that understanding. A specialist doctor told me to stop taking my temperature, that if I didn't pay attention to it, it would go away because it was all in my head." REUTERS/Susana Vera SEARCH "SPAIN LONGCOVID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

A combination picture shows long COVID sufferer Beatriz Perez, a 51-year-old computer engineer, posing for a photograph taken through blue plastic, and the staircase leading to Perez's flat photographed through blue plastic, in Fuenlabrada, Spain, March 4, 2021. The photographs were taken through blue plastic to visualise the effects of long COVID. Perez used to go trekking on weekends, but now is rarely able to complete her personal challenge of walking all the way down the stairs from her eighth-floor apartment, not to mention up. "One day I tried to at least go down the stairs and I don't even think I made it two floors down, I was in so much pain. I felt so disappointed. Am I ever going to be able to live a normal life again?" she said. Permanent fatigue, muscle and joint pain and forgetfulness have kept her off work for a year, and she says "the worst thing is living with the uncertainty" of not knowing when or if she will recover. Perez leads a daily mindfulness online class with other people who suffer from long COVID. "If it were not for meditation I might have already been put on antidepressants." REUTERS/Susana Vera SEARCH "SPAIN LONGCOVID" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES

Strangely, I can't clearly picture the face of the surgeon who changed my family's life. I'm not sure I'd recognize him if I bumped into him in the street. And yet I can vividly recall his face turning pale the instant he looked at the X-rays of my 14-year-old daughter's shoulder. Her chronic pain had first been diagnosed as a likely inflammation, and then possibly some problem in the muscle that could be fixed with a few physiotherapy sessions. But on that day, October 31, 2019, we found out that it was Ewing's Sarcoma, a rare and extremely aggressive form of bone cancer. The cancer had started deep in the sponge bone of her humerus and then broke out through the bone surface, causing excruciating pain, then metastasizing to several other parts of her body. Rebecca, or Becs, as we call her, was suddenly fighting for her life. REUTERS/Darrin Zammit Lupi SEARCH "REBECCA LUPI" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES TPX IMAGES OF THE DAY THE IMAGES SHOULD ONLY BE USED TOGETHER WITH THE STORY - NO STAND-ALONE USES

Student Wu Yunpeng, 22, flexes his muscles at Mi Fitness after the reopening of some of Beijing's gyms following closures enforced due to the outbreak of the novel coronavirus disease (COVID-19) in Beijing, China, May 8, 2020. Picture taken May 8, 2020. REUTERS/Thomas Peter

A closed sign is seen at Muscle Beach after California issued a stay-at-home order due to coronavirus disease (COVID-19) in Santa Monica, California, U.S., March 24, 2020. REUTERS/Lucy Nicholson

Kenta Kambara, 34, flexes his upper body muscles as he gets ready to perform at 'Challenge & Move' a dance event in Tokyo, Japan, February 8, 2020. Kambara who was born with spina bifida, a disorder that paralyzed his lower body, aims to perform at the Tokyo 2020 Paralympics opening or closing ceremonies. 'These days, people use the keyword 'diversity' but not many people have experienced it themselves,' he said. 'I want people to understand by seeing me dance that it's precisely because my body is different that it is interesting. Then that will become a trigger to accept other people's differences. REUTERS/Kim Kyung-Hoon SEARCH 'WHEELCHAIR DANCER' FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A man climbs up a wooden pole to get a prize in front of an Orthodox cathedral during celebrations of Maslenitsa, also known as Pancake Week, which is a pagan holiday marking the end of winter, in Vladivostok, Russia March 1, 2020. REUTERS/Yuri Maltsev TPX IMAGES OF THE DAY

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Ana Estrada, 43, a euthanasia advocate who suffers from an incurable condition that atrophies her muscles and has left her breathing through a ventilator, lies in bed at her home in Lima, Peru February 7, 2020. Picture taken February 7, 2020. REUTERS/Sebastian Castaneda

Zoey Tiemann who recently turned 5, and Zak Tiemann, 34, both stare into the mirror as they flex their muscles before Zoey's school's "superhero day" in Seguin, Texas, U.S., October 29, 2019. REUTERS/Callaghan O'Hare SEARCH "US MATERNAL MORTALITY" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Massage therapist Abdel Rehim Saeid performs the "fiery towel" method to ease a patient's muscle pain in Gharbia, Egypt September 4, 2019. Picture taken September 4, 2019. REUTERS/Mohamed Abd El Ghany

Massage therapist Abdel Rehim Saeid performs the "fiery towel" method to ease a patient's muscle pain in Gharbia, Egypt September 4, 2019. Picture taken September 4, 2019. REUTERS/Mohamed Abd El Ghany

Miriam Gutierrez's youngest son Joaquin, 6, touches her muscles as they take their dog for a walk in Torrejon de Ardoz, outside Madrid, Spain, May 27, 2019. Picture taken May 27, 2019. REUTERS/Susana Vera

U.S. President Donald Trump hecks out the muscles on cadet Nic Ready, who won the NCAA homerun hitting contest, as the president took part in the U.S. Air Force Academy's graduation ceremony in Colorado Springs, Colorado, U.S., May 30, 2019. REUTERS/Jonathan Ernst

U.S. President Donald Trump hecks out the muscles on an cadet who won the NCAA homerun hitting contest during the U.S. Air Force Academy's graduation ceremony in Colorado Springs, Colorado, U.S., May 30, 2019. REUTERS/Jonathan Ernst

Bodybuilders flex their muscles on stage during the 16th Southeast Asia Bodybuilding and Physique Sports Championships in Yangon, Myanmar, May 18, 2019. Photo taken on May 18, 2019. REUTERS/Ann Wang

Bodybuilders show off their muscles on stage during the 16th Southeast Asia Bodybuilding and Physique Sports Championships in Yangon, Myanmar, May 18, 2019. Photo taken on May 18, 2019. REUTERS/Ann Wang

Bodybuilders flex their muscles on stage during the 16th Southeast Asia Bodybuilding and Physique Sports Championships in Yangon, Myanmar, May 18, 2019. Photo taken on May 18 2019. REUTERS/Ann Wang

FILE PHOTO: An Iraqi woman walks back home to the southern city of Basra as fires rage in the distance April 3, 2003. British forces muscled into the outskirts of Iraq's second city of Basra capturing an industrial estate where Iraqi militia had spearheaded fierce resistance. REUTERS/Yannis Behrakis/File photo SEARCH "YANNIS BEHRAKIS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Ten month old Emiliano Cula, who has microcephaly, receives physiotherapy to try and stimulate control over his muscles in Luanda, Angola, September 6, 2018. Picture taken September 6, 2018. REUTERS/Stephen Eisenhammer

Ten month old Emiliano Cula, who has microcephaly, receives physiotherapy to try and stimulate control over his muscles in Luanda, Angola, September 6, 2018. Picture taken September 6, 2018. TO MATCH INSIGHT HEALTH-ZIKA/ REUTERS/Stephen Eisenhammer

A woman does her morning workout along the beach in Oceanside, California, U.S. August 30, 2018. REUTERS/Mike Blake

A detail of the Harley-Davidson brand name is photographed on the motorcycle of Guo Qingshan in his village outside Beijing, China, April 7, 2018. "I love the sound of the engine and the muscle of the motor. When I ride it, I feel free and proud," Guo said. However, Guo has his limits. If prices rise, Guo said he wouldn't contemplate buying another Harley. REUTERS/Thomas Peter SEARCH "TRADE PRODUCTS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Guo Qingshan poses on his Harley-Davidson motorcycle in his village outside Beijing, China, April 7, 2018. "I love the sound of the engine and the muscle of the motor. When I ride it, I feel free and proud," Guo said. However, Guo has his limits. If prices rise, Guo said he wouldn't contemplate buying another Harley. REUTERS/Thomas Peter SEARCH "TRADE PRODUCTS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. TPX IMAGES OF THE DAY

A caretaker wearing a motion assist equipment 'Muscle Suit' carries a resident from a bed to a wheelchair at Shin-tomi nursing home in Tokyo, Japan, February 5, 2018. REUTERS/Kim Kyung-Hoon SEARCH "KYUNG-HOON ROBOTS" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 18, 2018. REUTERS/Fredy Builes

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 18, 2018. REUTERS/Fredy Builes

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 18, 2018. REUTERS/Fredy Builes

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 18, 2018. REUTERS/Fredy Builes

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 18, 2018. REUTERS/Fredy Builes

Buddhist nuns help participants stretch their muscles during a five-day workshop teaching young women the martial art of Kung Fu, in Hemis region in Ladakh, India, August 18, 2017. REUTERS/Nita Bhalla

A wrestler displays her muscles as she performs at an all female wrestling event in London, Picture taken August 12, 2017. Britain August 12, 2017. REUTERS/Neil Hall

Floyd Mayweather Jr. of the U.S. works his abdominal muscles at the Mayweather Boxing Club in Las Vegas, Nevada, U.S., August 10, 2017. REUTERS/Las Vegas Sun/Steve Marcus

Hindu devotees display their muscles during the annual Rath Yatra, or chariot procession, in Ahmedabad, India June 25, 2017. REUTERS/Amit Dave

A robot that makes worm-like movements using soft actuators as "artificial muscles" is showcased at the National University of Singapore June 8, 2017. Picture taken June 8, 2017. REUTERS/Edgar Su

A group of about a dozen Republican governors is pushing for a new set of national health care reforms, flexing their considerable muscle in the national debate over the future of Obamacare as the U.S. Senate begins writing its own bill.

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 19, 2017. REUTERS/Fredy Builes

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 19, 2017. REUTERS/Fredy Builes

A participant flexes his muscles during the Mr. Olympia Amateur South America bodybuilding competition in Medellin, Colombia, February 18, 2017. REUTERS/Fredy Builes

Ryleah Geisner, 8, with reflective and surface EMG sensors attached to her body, walks in the Center for Gait and Movement Analysis lab at Children's Hospital Colorado in Aurora, Colorado, U.S., February 9, 2017. Ryleah has cerebral palsy, a congenital disorder of movement, muscle tone, or posture. The lab was using 3-D motion capture technology to analyze Ryleah's body movement and muscle activity while walking and that data will then be used to formulate a treatment plan for her. Picture taken on February 9, 2017. REUTERS/Rick Wilking

Ryleah Geisner, 8, with reflective and surface EMG sensors attached to her body, walks in the Center for Gait and Movement Analysis lab at Children's Hospital Colorado in Aurora, Colorado, U.S., February 9, 2017. Ryleah has cerebral palsy, a congenital disorder of movement, muscle tone, or posture. The lab was using 3-D motion capture technology to analyze Ryleah's body movement and muscle activity while walking and that data will then be used to formulate a treatment plan for her. Picture taken on February 9, 2017. REUTERS/Rick Wilking

Ryleah Geisner, 8, has reflective and surface EMG sensors attached to her body by Brittney Martz, clinical therapy aide (L) and Joanna Roybal, physical therapist (R,) before walking in the Center for Gait and Movement Analysis lab at Children's Hospital Colorado in Aurora, Colorado, U.S., February 9, 2017. Ryleah has cerebral palsy, a congenital disorder of movement, muscle tone, or posture. The lab was using 3-D motion capture technology to analyze Ryleah's body movement and muscle activity while walking and that data will then be used to formulate a treatment plan for her. Picture taken on February 9, 2017. REUTERS/Rick Wilking

Nune Karapefian (L) talks with staff after her daughter Ryleah Geisner, 8, walked with reflective and surface EMG sensors attached to her body in the Center for Gait and Movement Analysis lab at Children's Hospital Colorado in Aurora, Colorado, U.S., February 9, 2017. Ryleah has cerebral palsy, a congenital disorder of movement, muscle tone, or posture. The lab was using 3-D motion capture technology to analyze Ryleah's body movement and muscle activity while walking and that data will then be used to formulate a treatment plan for her. 2nd L is Joanna Roybal, physical therapist, 2nd R is Kayla Burnim, gait lab engineer and at right is Brittney Martz, clinical therapy aide. Picture taken on February 9, 2017. REUTERS/Rick Wilking

A computer image of the foot impressions of Ryleah Geisner, 8, is seen after she walked on a pressure sensitive floor wearing reflective and surface EMG sensors attached to her body in the Center for Gait and Movement Analysis lab at Children's Hospital Colorado in Aurora, Colorado, U.S., February 9, 2017. Ryleah has cerebral palsy, a congenital disorder of movement, muscle tone, or posture. The lab was using 3-D motion capture technology to analyze Ryleah's body movement and muscle activity while walking and that data will then be used to formulate a treatment plan for her. Picture taken on February 9, 2017. REUTERS/Rick Wilking