An unprecedented strike across American sport in protest at police brutality and racial injustice has continued into a second day, with NBA games again put on hold and several NFL teams cancelling training sessions in solidarity with growing calls for social change.

The boycott, which has sent shockwaves through the US, began on Wednesday when the Milwaukee Bucks refused to play the fifth game of their play-off match against the Orlando Magic in protest against the shooting of an unarmed black man, Jacob Blake, in Kenosha, Wisconsin, 45 miles from where they play.

Blake, who was hit seven times in the back by police as he opened his car door, is reported by his family to be paralysed from the waist down. Three of his children were inside the car. One Bucks player, George Hill, was asked why the team had decided not to play. “We’re tired of the killings and the injustice,” he replied. Flanked by his teammates, Hill read a powerful statement explaining why the Bucks had decided not to violate the no-strike rule in the NBA’s collective bargaining agreement.

“When we take the court and represent Milwaukee and Wisconsin, we are expected to play at a high level, give maximum effort and hold each other accountable,” he said. “We hold ourselves to that standard, and in this moment we are demanding the same from our lawmakers and law enforcement.

“We are calling for justice for Jacob Blake and demand the officers be held accountable. For this to occur, it is imperative for the Wisconsin state legislature to reconvene after months of inaction and take up meaningful measures to address issues of police accountability, brutality and criminal justice reform.”

Another Bucks player, Sterling Brown, has an outstanding lawsuit against the city of Milwaukee, the police chief and eight officers after he was tasered and arrested following an altercation stemming from a parking violation.

This was the first time since 1992, in the aftermath of the Rodney King riots, that an NBA playoff game had been postponed. Before then, the only other time it had happened was following the murder of Dr Martin Luther King in 1968. Two more NBA games were postponed on Wednesday and for a while it seemed that the season might be in jeopardy.

That threat appears to have subsided, with reports on Thursday suggesting the players have pulled back from the brink and will resume play-off matches in the coming days. Further meetings are also planned between NBA owners and the league’s star players to discuss doing more to tackle social justice issues. There is hope that a consensus will be reached given that the NBA is America’s most progressive sports league, with players encouraged to speak out about political and social issues.

During the playoffs, which are taking place in a socially isolated “bubble” at Disney World in Florida because of the Covid-19 pandemic, the league has painted the words “Black Lives Matter” on the court. Meanwhile coaches, players and referees kneel before games to protest police brutality following the killing of George Floyd, who was killed in May by a policeman who kneeled on his neck for more than eight minutes.

However there is growing anger among NBA players, 80% of whom are Black, at the social injustice seen daily on the streets of America. As LeBron James, arguably the league’s best player and one of the most famous athletes in America, bluntly put it on Twitter on Wednesday evening: “Fuck this man. We demand change. Sick of it.”

On Thursday James, a long-term advocate for racial justice and a man often seen as the voice of the NBA, urged his 47 million followers to vote to change America for the better. “Change doesn’t happen with just talk!!” he wrote. “It happens with action and needs to happen NOW! For kids and communities across the country, it’s on us to make a difference. Together. That’s why your vote is @morethanavote #BlackLivesMatter.”

The wave of protests that began with the NBA quickly spread to other sports on Wednesday with five MLS games, three MLB games, matches in the Western & Southern tennis tournament and three WNBA women’s basketball games, all called off as athletes acted in solidarity with Bucks players. Several WNBA teams were also seen wearing white T-shirts with Blake’s name on the front and seven bullet holes on the back.

The former US president Barack Obama tweeted his support of the Bucks, saying he commended the players for standing up for what they believe in and the NBA and WNBA for setting an example to others. “It’s going to take all our institutions to stand up for our values.”