The protests that spread around the world after the death of George Floyd have prompted many in the public eye to raise their voices to speak about racial injustice and police brutality, including leading athletes.
Some who have resumed play during the coronavirus pandemic have expressed their views on the field of play, kneeling or including messages on their uniforms demanding justice.
But will they be able to do the same on the biggest sporting stage of them all — the Olympic Games next summer?
The answer, at least for now, remains unclear.
Rule 50 of the Olympic Charter bans any form of protest — whether political, religious or racial — during the games.
In January, the International Olympic Committee, or IOC, issued a set of guidelines that reaffirmed the ban on displaying political messages at the Olympics. They also prohibited political gestures, including kneeling.
Earlier this month, IOC President Thomas Bach was asked by reporters whether athletes at next year's games in Tokyo, postponed because of the coronavirus pandemic, would be allowed to kneel on the medal podium.
Bach deferred to the IOC Athletes Commission, which he said will consult with athletes and come back with "relevant proposals."
In the wake of Bach's words, the athlete-led movement Global Athlete called on the IOC to abolish Rule 50, saying: "Athletes have had to choose between competing in silence and standing up for what's right for far too long. It is time for change."
While the IOC has been adamant about keeping the Olympics neutral, acts of protest at the games are nothing new.
One of the most memorable took place at the 1968 Summer Olympics in Mexico City, when two medal-winning Black American runners, Tommie Smith and John Carlos, stood on the podium with fists raised and heads bowed during the national anthem to protest the treatment of Black Americans. Both were suspended from the Olympic team and booted from the Olympic village.
Years later, two Cold War rivals staged protests of their own. The United States boycotted the 1980 Summer Games in Moscow over Russia's invasion of Afghanistan the year before, and the Soviet Union responded four years later by boycotting the Summer Games in Los Angeles.
Full coverage of George Floyd's death and protests around the country
Middle Eastern politics came to the fore at the 2004 Summer Olympics in Athens, when Iranian Judoka Arash Miresmaeili refused to fight his Israeli opponent, winning praise back home.
More recently, Ethiopian marathon silver medalist Feyisa Lilesa crossed the line at the 2016 Summer Olympics in Rio de Janeiro with his wrists crossed as if shackled in protest of the treatment of demonstrators in his country. He had to go into exile for two years.
'A massive shift in official line'
If the IOC changes its stance on protests, including taking a knee, it will be a massive shift for the organization, said Martin Polley, a sports historian at De Montfort University in Leicester, England.
"The IOC is clearly thinking about precedents and the moments in the past when it has been on the wrong side of history," Polley said.
He pointed to the 1936 Summer Olympics, hosted by the Nazi government in Berlin, that were, he said, "a huge state-run political propaganda display that is embarrassing to look back on."
He said other missteps included the expulsion of Smith and Carlos after their protest and Chinese security personnel's accompanying the 2008 Summer Olympics torch relay, quashing any attempts at disruption by human rights activists.
"But we also need to remember that the IOC was one of the first international sports organizations to expel apartheid South Africa in the early 1960s, an expulsion that ended in 1992, and that its recent work on creating refugee teams has given opportunities to athletes displaced by war and political turmoil," Polley said.
It will be important for the IOC to acknowledge "official political symbolism" that goes on in and around the Olympics, Polley said, including flags, anthems and patronage by politicians and heads of state who are not politically neutral.
"If the IOC now allows competitors to take the knee in support of Black Lives Matter, it will suggest that the conversation on the political nature of international sport is becoming more nuanced and mature and that athlete activists and allies will no longer have to make the difficult choice between compromising their ideals and jeopardizing their careers," he said.
But should the IOC decide to loosen its restrictions, society will have to grapple with the fundamental issue of whether protests make a difference when they are permitted, said Andy Miah, who co-wrote a book on the Olympics.
"To protest is to defy rules or conventions, and the strength of the message, the symbolic act, can be diminished if it becomes permissible," Miah said. "There may be some value in maintaining the rule, if only to ensure that any protests retain the gravitas that they deserve."
Sports leagues react to George Floyd protests
The NFL has been a flash point for protests over police violence since 2016, when Colin Kaepernick began kneeling during the national anthem before games to highlight police brutality and racial inequality. Kaepernick has not played in the league since, but he has emerged as a leading voice of opposition to police violence.
In 2018, the league said all players on the field when the national anthem was heard before a game must stand. But in the wake of Floyd's death, Commissioner Roger Goodell apologized to players for not having listened to their concerns about racism sooner.
In England, Premier League players took a knee before kickoff in support of the “Black Lives Matter” movement, as matches restarted Wednesday after a 100-day hiatus due to the COVID-19 pandemic.
The players’ names on the backs of their shirts had been replaced by the words “Black Lives Matter.”
Meanwhile, the U.S. Soccer Federation last week repealed its requirement that players stand during the national anthem, saying it was ready to support its athletes in "elevating their efforts to achieve social justice."
Sebastian Coe, president of World Athletics, told NBC News last week that he was "reluctant to discourage athletes from expressing their views," adding that there is nothing in the organization's code of conduct to prevent athletes from protesting as long as it is done "in a respectful manner."