- Many professional footballers have tested their skills in the boxing ring
- Wayne Rooney is currently in talks with influencer Boxing Promotion Misfits
- Watching training while injured at the gym is like your missus walking down the street with another guy – just ask It's all kicking off Internet
Endurance, discipline and work ethic are essential traits to rise to the top as a professional footballer.
Coupled with the natural athleticism found in fighters, it's no surprise that over the years, there have been crossovers from the pitch to the ring.
Whether it's early years spent in an amateur gym, a charity fight after retirement or a full-scale career change, many footballers have tested their skills in the sweet science.
For better or worse this group of players broke away from the game's safety and challenged themselves in one of the sport's most unforgiving ways.
With the news that Wayne Rooney is stepping into the world of influencer boxing to sign with KSI's Misfits Promotion, we look back at eight fighters who tried their hand at boxing.
Rio Ferdinand
Renowned as one of England's greatest defensive talents, Rio Ferdinand enjoyed a glittering career as a professional footballer spanning two decades.
The centre-back broke the British transfer record twice and, upon arriving at Old Trafford in 2002, quickly established himself as one of the club's key players in the final years of Sir Alex Ferguson's all-successful reign.
After more than a decade in Manchester, Ferdinand endured a less successful year at QPR before calling time on his career in 2015.
Although that retirement marked the end of his football career, Ferdinand's sporting ambitions saw a new venture into professional boxing.
At the age of 39, in 2017, Ferdinand announced his transition to boxing, with a documentary to be filmed following his transition to a career in combat sports.
Within a year of starting his training regimen, Ferdinand was denied a boxing license by the British Boxing Board of Control and retired from the ring, appearing frequently on TNT Sport as a pundit.
Wayne Rooney
Wayne Rooney, who joins his former Manchester United team-mate on the list, could step into the ring this year if negotiations with Misfits Boxing work out.
However, unlike Ferdinand, Rooney has a background in pugilism, having trained in the sport as a teenager before becoming a teenage sensation at Everton.
Despite his various successes in football, Rooney's love of boxing never wavered throughout his career and he was often seen in high-profile fights and maintained a close friendship with Ricky Hutton.
But the former United captain's love of the game's infamy isn't just visual.
In 2015, footage emerged of Rooney collapsing in his kitchen with former United teammate Phil Bardsley.
Rooney saw the funny side and mocked the incident a few days later with a poor goal celebration against Tottenham.
Wayne Bridge
Wayne Bridge, who has 36 England caps, would no doubt have scored countless victories had he not been in his prime had he been forced to compete with Ashley Cole for a place in the national team.
Having won everything available domestically at Chelsea, Bridge would spend time at Manchester City, West Ham, Sunderland, Brighton and Reading before hanging up his boots in 2014.
Although his career on the pitch is over, Bridge remains active and was chosen to showcase his budding skills in the ring for charity at Sport Relief 2018.
Taking on reality TV personality Spencer Matthews, Bridge dominated his hapless opponent and twice forced the Made in Chelsea star to the canvas.
Although Matthews survived to see the final bell, Bridge dominated and was declared the winner after three two-minute rounds.
Roy Keane
Known for his intensity, aggression and endless stamina, it's no wonder Roy Keane donned the gloves briefly in his youth.
Taking up the sport aged nine, Keane followed his brother to a local amateur boxing gym in Cork.
While his brother went full steam ahead in training, the younger Keane was forced to juggle his boxing duties with a burgeoning football career for local team Rockmount.
Although his time in the ring was short, Roy had several amateur fights, winning them all before turning his attention to football.
Speaking about the experience on Sky's Stick to Football podcast, Keane expressed his love for the game.
'My brother had about 50 amateur fights, but I had four. I'm not defeated, you know what I mean. When you're young in training it's great, it's brilliant, I love everything about it and the discipline.
Tommy Martin
Like Keane, Tommy Martin was once faced with the decision of whether to continue his football career or get serious about boxing.
The Chelmsford-born light-welterweight was on the books at Peterborough United after developing as a talented young goalkeeper.
However, despite being offered a scholarship by Bosch, Martin knew his true passions lay elsewhere.
'As soon as I walked into the gym I thought, 'I don't want to be on a cold, muddy football pitch – someone punching me in the head in the gym'. Martin told BBC Radio Cambridgeshire.
Martin, who made his professional debut in 2012, would soon be recognized as one of Britain's premier talents at 140lbs, defeating Ricky Boylan for the English title in 2015.
However, his in-ring career would eventually end in tragedy.
A year after his historic title win, Martin faced John Wayne Hibbert for the Commonwealth belt and was knocked out in the twelfth and final round of the back-and-forth clash.
Martin suffered a brain haemorrhage during the collision and was subsequently forced to retire from the sport.
Katie Taylor
Undoubtedly the most successful fighter on this list, Katie Taylor has combined an unprecedentedly successful amateur run with multiple world titles as a professional.
However, before his boxing triumphs, the 37-year-old's first showcase on the international stage came as a midfielder.
After playing the sport as a schoolgirl, Taylor played for various teams in the Dublin area and represented the Republic or Ireland at several youth levels.
Taylor then made 11 appearances for the senior team, scoring for his country in Euro 2009 qualifiers with Italy and Hungary.
Domestically Taylor won a treble with Beamount United in 2010 as the club won the Dublin Women's Football League, DWSL Premier Cup and FAI Women's Cup.
She was carving out a career as one of the most decorated amateurs in women's boxing history, counting Olympic gold among her many titles before turning pro in 2016.
Leon McKenzie
Unlike some of his contemporaries on this list, when Leon McKenzie chose to start a boxing career after hanging up his boots, he did it the hard way.
Playing in all four divisions of English football, McKenzie was an integral member of Nigel Worthington's Norwich side that won promotion to the Premier League in 2004, netting nine times in just 12 starts.
McKenzie would go on to record seven more goals as the Canaries' joint-top scorer once back in the top-flight, but the club could not avoid being relegated at the first attempt.
After a brief stint in non-league football, McKenzie decided to make a career change and made his professional boxing debut in 2013 at the age of 35.
Initially cutting his teeth against journeymen, McKenzie quickly rose through the ranks and won the English super-middleweight title with a first-round stoppage of Kelvin Young.
Although he ultimately failed in his pursuit of domestic glory, McKenzie's 8-2-1 record is undoubtedly respectable, especially considering his age when he first donned the gloves.
Curtis Woodhouse
While Curtis Woodhouse is neither the best football player nor the most skilled fighter to feature on this list, his accomplishments in both earn him the title of one of football's greatest boxers.
Starting his career with York, Woodhouse would soon be snapped up by Sheffield United, making his senior debut with the Blades in 1997 before joining Birmingham.
Woodhouse made 28 appearances in the West Midlands during the 2001–02 season as Steve Bruce led the club to fifth place in the Championship, although he was left out of the team as they beat Norwich on penalties in the play-off final.
Although his opportunities in the top flight proved limited, Woodhouse made several substitute appearances in the Premier League before earning more playing time away from St Andrews.
After spells at Peterborough, Hull and Grimsby he said he had 'lost his love for football' and chose to turn to a career in the ring aged 26.
Initially accused of being a gimmick, Woodhouse quickly proved himself by winning several domestic titles, including the British light-welterweight belt, before retiring in 2017 with 24 wins and 7 losses.