It's quite common across all sports.
These are only a small number of the high profile examples that have gone public:
John Terry
Chelsea's captain took painkilling injections to play in April days after he cracked two ribs in the first leg of the Champions League quarter-final against Benfica. He was forced off a week later in the second leg, complaining of breathing problems. The 31-year-old centre back has a long history of playing through pain that stems from persistent injuries to his back and knee.
Kelly Sotherton
The former heptathlete, who won a bronze medal at the 2004 Olympics in Athens, said she "never" started a competition 100 per cent fit and free from medication. The 35-year-old retired last month after failing to recover from back surgery in time to compete at the London Games.
Lleyton Hewitt
Australia's former world No 1 tennis player lost in the first round of this year's French Open but said it was good "not to have pain" following successful surgery. This was required after doctors refused to give him any more painkilling injections for recurring toe problems. Previously, the 31-year-old said he had not been pain-free since last March and needed injections for "pretty much every match I played".
Richie McCaw
The captain of the New Zealand rugby union team started last year's World Cup with a problem with his foot. He had fractured it in February and needed surgery, but the pain got worse in the showpiece tournament and required painkillers. During the event the 31-year-old openside flanker became the first All Black to reach 100 Test matches. He went on to play in the final and lift the cup.
Andrew Flintoff
The celebrated cricketer blames England's 2009 Ashes campaign for ending his career. The 34-year-old all-rounder retired in 2010 after failing to overcome a chronic knee problem. Playing against Australia, he was given a huge number of painkilling injections to help him stay in the series, but ended his career saying his knee was "in bits".
Gavin Henson
His career may have gone off the rails this year but Henson, 30, made a winning return to Wales's rugby union side in 2008 after a two-year absence. He played in their Six Nations victory over England at Twickenham but needed a painkilling injection at half-time as he struggled with an Achilles injury. He played in every game with that Grand Slam-winning side, but is now without a club.
Paul Lawrie
The 1999 Open champion golfer has had a foot injury for a year. He was to have surgery last winter but a return to form has seen him playing on with painkillers.
Kobe Bryant
The US basketball star, who has just finished his 16th season with the LA Lakers, manages a long-standing wrist problem with injections before a game and ice wraps afterwards. Bryant, 33, also wears an immobilising brace to hold it in place off court. American footballers also admit to using painkillers, including the Philadelphia Eagles quarterback Michael Vick and the Chicago Bears linebacker Brian Urlacher.
https://www.independent.co.uk/life-...orts-stars-risking-their-careers-7818047.html