Athletes who perform at the elite level aren't like the rest of us. Their feats of strength, accuracy, and endurance often appear superhuman — which probably explains why we enjoy watching them so much. And the suggestion that many of these athletes are somehow performing outside of "normal" human bounds is not an exaggeration. Professional sports, it would seem, are being increasingly dominated by the mutants among us.
Humanity is a pretty diverse bunch. We come in all shapes and sizes, and with varying gifts. And it just so happens that some of these variations can lend themselves to specific sports. Some people benefit from happy accidents — physical "mutations" that can help an athlete adapt to a particular sport. It's Darwinian selection on the playing field, with athletes working to attain Dawkinsian fitness peaks (quite literally).
The result of this selectional process is that the last man and woman standing are often way outside the human norm.
Perhaps the most obvious example of an advantage in sports are extreme physical proportions.
Basketball is probably the best example. The average height of an NBA player today is around 6' 7", which contrasts to the average American male's height of 5' 10". Height is a particularly potent weapon in basketball because it allows a player to shoot the ball over a shorter distance to the net. Tall players also start out closer to the rebound, and they can reach higher into the air to block rebounds.
That said, NBA basketball players are shorter today than they were during the late 1980s, when average height was around 6' 7.36". A possible explanation for the decrease is that too much height starts to confer a disadvantage in other areas, such as speed and agility. Given that the height of NBA players has remained relatively stable over the past decade, it's likely that elite players have settled around a kind of "goldilocks zone."
Height is deadly in other sports, as well. Soccer players, who have to compete for the ball in all three dimensions, are getting progressively taller. There's also an arms race in ice hockey, in which defensemen are having to get taller in order to compete against increasingly bigger power forwards. It's no coincidence that the NHL's best defenseman, Zdeno Chara, is also its tallest at 6' 9" — a height that is absolutely unprecedented for that sport.
There's also limb length to consider. The relatively new sport of mixed martial arts is seeing a trend of fighters who have disproportionately long arms and legs. In fact, the sport's best fighter, Anderson Silva, is nicknamed "The Spider" — and for good reason. Added reach allows a fighter to get "inside" on his opponent where he can unleash a barrage of punches, while still preserving his defense. The best example of this is light heavyweight champion, Jon Jones, whose arms extend an incredible 84.5" (the average for his weight class is 76.23").
Performance advantages can also come about as the result of shorter, smaller statures. Jockies, with their average weight of 115 lbs, are well below the norm.
Different on the inside
Bodily proportions are certainly a key indicator of potential success, but there are other physical intangibles as well — some that aren't so visibly obvious, but can be measured nonetheless.
Jamaican sprinter Usain Bolt is a good example. Lightyears ahead of the competition, Bolt hits the ground with a force that's around 2.5 times his body weight (most people can muster around two times). And when his foot lands, it applies about 900 lbs of force for just a few milliseconds.
This is similar to the genetic advantage that gives Olympic weightlifters their "burst" strength. Elite weightlifters are able to engage more of their fast twitch muscle fibers than most people.
Cardiovascular capacity is another important factor, particularly for endurance sports. Heart size and oxygen utilization can be improved through training, but some athletes have a distinct advantage in this area that can only come about by a genetic endowment. Cyclist Bradley Wiggins is a good example. He has a left ventricle in his heart that is abnormally large, allowing him to supply an extreme amount of blood to his muscles during a race. For most people, that blood supply is like trying to fill up a bath with a thimble, but it's as if Wiggins has a bucket.
A strong indicator of a big, healthy heart is resting heart rate. A normal person at rest exhibits about 70 beats per minute — but elite endurance athletes are typically clocked at 40. The cyclist Miguel Indurain is reported to have a resting heart rate of just 28 beats per minute.
But cardiovascular endurance can extend beyond that. Some athletes, Wiggins included, also have elevated levels of mitochondria in their cells — which helps their muscles to use the added volume of oxygenating blood. Wiggins, like other athletes, have an entire cocktail of genetic endowments that make them the elite of the elite.
"Designed" to swim
Indeed, perhaps the one athlete that best exemplifies the perfect storm of physical and physiological advantages is swimmer Michael Phelps. In fact, the closer you look at Phelps, the more convinced you are that he was somehow designed to be a swimmer.
Most people have a wingspan that matches their height. Not Phelps. He may be 6'4" tall, but his arms extend outward to a total of 6'7". The average shoe size for a person the size of Phelps is 12; he wears a size 14 which gives him a 10% advantage over the competition. He also has a larger than average hand size which allows him to move more water. Phelps is double-jointed in the chest area, enabling him to extend his arms higher above his head and pull down at an angle that increases his efficiency through the water by as much as 20% — what also allows him to have quicker starts and turns.
And there's more. His unique physique reduces drag through the water and allows for maximum propulsion. Phelps has a greater-than-average lung capacity allowing him to execute his underwater dolphin kicks longer than the competition. He has a genetic advantage that cause his muscles to produce 50% less lactic acid than other athletes, which means he can work at higher workloads for longer periods. And with a low body fat of 4%, he is better able to convert his effort into speed.
Phelps is unreal — and he's clearly swimming in a genetic pool of his own.
As tough as it is to admit this, biological advantages are probably the most important factor when considering an athlete's success. There's no question that dedication, training, skill, and access to coaches and facilities are important as well, but they are, for the most part, things that most athletes have anyway — particularly at the pro level. Having to set those factors aside, it's typically the mutants who get to stand on top of the podium.