By Rock Mayock 7:00 p.m. | In case you missed it, Tennessee Titans running back Chris Johnson has issued seemingly the most audacious of proclamations. In a recent interview with the Tennessean, Johnson asserted that he would beat the world’s fastest man, Usain Bolt, in a 40-yard footrace. On the surface this claim appears to be nothing more than self promoting bravado, but is there actually something to it? Let’s break down the numbers and the video footage.
If we reflect back to February 2008, an unheralded running back from East Carolina University by the name of Chris Johnson ran the 40 in a remarkable 4.24 seconds at the NFL Scouting Combine. Johnson’s 40 time catapulted him from a projected late 2nd to early 3rd round draft pick to the 24th overall pick by the Tennessee Titans.
Later that Summer, a young Jamaican sprinter by the name of Usain Bolt exploded into a global phenomena as he dominated the world of track and field during the 2008 Beijing Olympic Games. At the Beijing Games, Bolt established new world records in the 100m and 200m sprints. In the 2009 IAAF World Championship Track and Field, Bolt went on to shatter his previous 100m record (9.69 seconds) with a superhuman time of 9.58 seconds thereby establishing himself as the fastest man to walk the Earth not named The Flash.
On the surface it would seem the argument of whether or not Chris Johnson could beat Usain Bolt in a footrace is ridiculous. After all, Bolt is the undisputed fastest man alive. However, a second look at the argument within the right context things become more intriguing.
There are a couple of metrics to focus upon when watching tape, the split time and the stride length. Split time refers to how fast the runner crosses the first 10 yards or 10 meters of a race. It indicates how fast the runner is getting off the line and up to full speed. Stride length is an important because it dictates how much ground a runner can cover per footfall. The typical stride length for a world class runner is 1.14 times the runner’s height.
A good analogy to illustrate this point is how torque management and curb weight effect a car’s performance. Poor low end torque management results with more wheel spin during acceleration where as efficient low end torque management places rubber to asphalt in order to enable quicker acceleration. Likewise it takes more effort to move a heavy vehicle (high curb weight) forward than it does to move a light one (low curb weight). Therefore a low curb weight car with efficient low end torque management is able to achieve a faster 0-60 time. Now substitute 0-60 time for split time. A low split time means that a sprinter can achieve top speed faster.
Let’s continue with the automotive example. It’s conventional wisdom that a car’s top speed is a function of different factors which include engine size (displacement), horsepower, and curb weight. Assuming that it fit (or you made it fit), imagine that you dropped a 6.2L LS9 V8 supercharged engine in your ‘94 Pontiac Trans Am. You know that an engine of that size and horsepower (638 hp) combined with the 3,500lb vehicle curb weight would result with a top speed of approximately 197 MPH, thereby making it the fastest car on your block. Now substitute horsepower with stride length. A long stride length equates to more horsepower and greater maximum speed.
Using this information we can now evaluate how it applies to Johnson and Bolt. Let’s look at the numbers:
Johnson’s 1.53 second 10 meter split is world class. His stride length should be 6 feet 9 inches however it is actually an atypical 7 feet 6 inches. This indicates that his max speed (estimated to be 23.6 MPH) is well above what it should be. Chris Johnson is the sprinter equivalent to a Nissan GT-R. Compact, low to the ground with low curb weight and incredible 0-60 speed.
Usain Bolt by the numbers is mind boggling. Standing 6 foot 5 inches, he is freakishly tall for a sprinter. His height translates into an 8 foot 1 inch stride length which is actually shorter than the 8 foot 7 inch stride length that would be predicted for a runner of his stature. Bolt’s stride length enables him to cover anywhere between 1/2 to a full foot of distance per stride than his competitors. The lone weakness to his game is his 10 m split which. Due to his size, it takes Bolt nearly 1/3 of a 100 m race to achieve his full sprint speed. Once he achieves full speed his is unbeatable. Usain Bolt is the sprinter equivalent to Dom Toretto’s 1970 Chevelle SS. Slow off the line but it’ll smoke the field after the first quarter mile.
Now let’s look at the game tape:
Chris Johnson’s 10 yard split time recorded at the Combine was a record setting 1.40 seconds. Using the power of algebra we can use Johnson’s 10 yard split time to extrapolate his 10 meter split time of 1.58 seconds. Therefore Johnson goes from zero to full speed in roughly 1.5 seconds. This means that Johnson reach his max speed of 23.6 MPH within the first 1/4 of a 40 yard/40 meter footrace. This makes him a formidable opponent.
During Bolt’s record setting 100m sprint at the 2009 IAAF World Tack and Field his 10 meter split was recorded as 1.85 seconds. Because Bolt’s stride length is so long it takes him additional footfalls to reach his top speed of 27.45 MPH. Typically Bolt does not reach full speed until he crosses the 1/3-1/2 half point of a race however once he does he easily pulls away from the field because 27.45 MPH is unbeatable.
Ultimately this is a question of whether or not a top tier athlete can best a world class athlete. The bottom line is that Chris Johnson ran a fast 40 at the Combine, but he does not even own the record for the fastest 40 at the Combine. That honor belongs to Bo Jackson who ran the 40 in a verified 4.12 seconds at the 1986 Combine (BOING!). Therefore Chris Johnson isn’t even the fastest athlete within his own sport.
Conversely, Usain Bolt is a living legend. According to the Population Reference Bureau, 108,000,000,000 people have lived on Earth. Of those 108 billion people, Usain Bolt is recognized as the fastest. Is it likely that Bolt can run a 40 yard dash in 3.5 seconds (per algebraic estimation)? Probably not, that would make him faster than a Corvette ZR1. Could Bolt run a 40 at 4 seconds or maybe an eyelash less? Possible. Any way you cut it, he would beat Johnson. Regardless, we would totally watch the race just like we watched Chad Ochocinco race a horse.