It's no secret Usain Bolt is contemplating a career change. Not content with a trophy cabinet full of athletics gold, the world's fastest man has openly expressed an interest in playing for both Manchester United and the Jamaican national side.
But can his track speed really transfer to the pitch? If so, should all clubs be sending their scouts to athletic tracks to look for their next signing?
Perhaps those sprinters not quite making the professional ranks should consider a career move to a more lucrative sport? Or is this concept of "track speed" very different to "football speed"? Research in the area of sports science would suggest it could be the latter and Bolt could be in for a rude awakening should he make the transition.
Firstly, it must be noted that, in theory, recruiting the world's fastest man is a massive weapon to have in your arsenal. He's effectively been trained and moulded for years into a speed machine. Surely he would be no match for a professional footballer who'd be pedestrian in comparison.
This was certainly the case in the sport of rugby, where former American sprinter Carlin Isles, dubbed "the fastest player in rugby," successfully made the transition. One look at the below YouTube video, which now has over five million views, and it's clear to see how his speed has been such an asset.
The Jamaican bobsleigh team of 1988 is another well-known example, with other countries since recruiting their athletes from the athletics track.
To use a football-specific example, Kim Song-Hui of the North Korean women's football team was also a promising sprinter earlier in her career and successfully changed sports. She has since represented North Korea at the 2012 Summer Olympics and scored their two opening goals of the tournament against Colombia.
Then, of course, American football has recruited many athletes spawned from the sport of sprinting.
According to an article published on the NFL website entitled "Olympians in the NFL," Bob Hayes is considered the most successful sprinter to make the transition to the NFL. Winning two gold medals in 1964 during the Tokyo games in the 100 metres and 4x100 metres relay, he later played for the Dallas Cowboys, was a three-time Pro Bowler and was selected to the Pro Football Hall of Fame in 2009.
Jim Hines, the first man to ever run under 10 seconds for 100 metres, also won two gold medals at the 1968 Games in Mexico City and later played one season with the Miami Dolphins in 1969.
Finally, to use a modern example, Levonte "Kermit" Whitfield, a Florida 3A state champion capable of running 10.21 seconds for the 100 metres, is also a man who ran an incredible 100-yard kickoff return made famous by ESPN in this video.
Football statistics also seem to favour Bolt's move. According to the Daily Mail, Gareth Barry only reaches speeds of 18.41 mph during a match. Bolt, on the other hand, managed to reach a top speed of 27.79 mph when he broke the world record for the 100 metre back in 2009, as reported by BBC Sport.
So it seems he probably has good reason to be confident. Talking about playing for Manchester United, back in 2012, he was quoted in The Guardian saying: "I am a very accomplished player and know I could make a difference. I would be the fastest player in the team, but I can play as well."
But would he really be the fastest player on the pitch? Research reveals probably not since this concept of "track speed" is very different to "football speed," meaning Bolt’s world-famous confidence may be misplaced this time.
Firstly, the "track speed" possessed by Bolt occurs in a straight line over 100 metres with no change of direction and therefore no need for agility. In contrast, "football speed" occurs over much shorter distances and requires the player to accelerate quickly and repeatedly in many different directions whilst anticipating the change of play. Essentially, "track speed" requires pure speed, but "football speed" requires agility too.
What’s worse for Bolt’s football career is a study conducted at the New South Wales Institute of Sport, Sydney, Australia, argues the two are distinctly separate. After subjecting 21 male footballers to a series of tests, researchers wrote in the Science and Football IV that "agility and speed in soccer players are two different performance parameters."
What this means is whilst Bolt is able to achieve a top speed of 27.79 mph, this has nothing to do with his agility. Scientists believe the reason for this difference could be a result of many variables, including a player's ability to decelerate quickly, anticipate changes in motion and accelerate quickly.
This last variable could be a particular problem for Bolt, who famously struggles to get his 1.95-meter, 94-kilogram frame out of the blocks and immediately accelerating. Nowhere was this more evident than during his Diamond League victory in Zurich in 2013 where, after a very slow start, he finally got up to speed between the 60-metre and 80-metre mark to win gold.
If you watch the video, you’ll see it’s only after five seconds that he really begins to accelerate and overtake the rest of the field.
This could be useless for "football speed." Scientists at the University School of Physical Education in Poznan, Poland, who researched the sprinting movements of 147 players during 10 UEFA Europa League matches, found that "90 percent of sprints performed by professional soccer players were shorter than five seconds."
Ultimately this means the shorter distances, agility and acceleration needed for football could prove to be a problem for Bolt. He could find himself second to the ball every time to players whom he’d leave for dead on an athletics track.
But the final proverbial nail in the coffin of Bolt’s football career comes in the form of a laboratory test in which Cristiano Ronaldo competed against Spanish 100-metre sprint champion Angel David Rodriguez Garcia.
It appears Ronaldo lost the straight-line 25-metre sprint partly due to the biomechanics of his running style. But that exact same style meant he was almost half a second quicker during the 25-metre zig-zag sprint designed to test agility.
This is because his shorter running stride and lower centre of gravity enabled him to decelerate quickly, anticipate changes in motion and accelerate quickly. The exact traits identified in the aforementioned study were conducted at the New South Wales Institute of Sport.
The linear "track speed" of sprinting does transfer very well into some sports such as bobsleigh where athletes are only required to move in a straight line. Or rugby and American football where players require less dexterity in the feet, sprint for longer distances and are discouraged from running backward.
But based on the evidence, it doesn’t transfer ever so well into "football speed," if at all.
All things considered, it appears whilst Bolt is undoubtedly the quickest man on a track, he may not be the quickest on a football pitch. That probably explains why Kim Song-Hui remains the only successful sprinter to transition into football and why more sprinters aren’t exchanging their spikes for football boots.
Ultimately, this means that, contrary to popular belief, his chances of playing for Manchester United or Jamaica lie in his unknown footballing ability and unknown "football speed." But certainly not in his "track speed," which science shows has little benefit on the football pitch.