Britain’s world heavyweight champion Anthony Joshua wore a knee brace as a “precautionary measure” at a Black Lives Matter march.
Joshua, 30, was seen using a scooter during parts of the march in his home town of Watford.
The IBF, WBA and WBO world champion felt a “twinge” in his left knee during training this week.
“It will be further checked by his doctors but there is no immediate concern,” his spokesman said.
“The brace is a precautionary measure on the advice of physios.”
Joshua addressed the crowd, who marched in protest following the death of American George Floyd.
Floyd, 46, died while being arrested on 25 May in Minneapolis. The four officers involved have since been charged over the death, which sparked days of protest in the US and Black Lives Matter demonstrations across the world.
Joshua read out a poem describing racism as a “pandemic”.
“We stand united against a virus which has been instrumental in taking lives, taking lives of the young, old, rich, poor; a virus which is unapologetic and spreads across all sectors,” he said.
“The virus has been declared a pandemic. This is out of control. And I’m not talking about Covid-19. The virus I’m talking about is called racism.”
Joshua hoped to fight twice in 2020 but has accepted he will have no more than one bout this year because of the coronavirus pandemic.
Talks are ongoing over when and where his mandatory world title defence against Bulgaria’s Kubrat Pulev can take place given the challenge faced in creating a viable event without fans present.
Ideas have been floated by Joshua’s promoter Eddie Hearn on the prospect of a bout at Royal Albert Hall where only a small number of high-priced seats are sold. Pulev’s team have raised the prospect of fighting outdoors at a Roman amphitheatre in Croatia.
Those close to Joshua expect his injury to have no impact on plans to face Pulev and insist he will be able to return to normal training in the short term.