At this month’s Summer Olympics in Rio, the world’s fastest man, Usain Bolt — will try to beat his own world record of 9.58 seconds in the 100-meter dash.
Whereas a great number of training techniques and technologies continue to push the boundaries of athletics, the slowing pace at which sporting records are now broken has researchers speculating that perhaps we’re approaching our collective physiological limit.
In 2008, running enthusiast and biologist Mark Denny published a study attempting to determine if there are absolute limits to the speeds animals can run. Denny was able to conclude that there is indeed a predictable limit to the time it takes for a particular species to cover a certain distance. In fact, his data show that horse and dog racing as well as some human track and field events may already be there.
Usain Bolt hopes to beat the researcher’s fastest predicted 100-meter dash time of 9.48 seconds.
For physiology professor Peter Weyand, one of the leading experts on the biology of performance, we humans haven’t quite reached our athletic ceiling. Weyand explains that when considering endurance, for example, there are two paths to improvement: either increasing the amount of blood being pumped out of the heart or increasing the oxygen concentration in the blood itself, as is the case with blood doping. “I think people will find ways to enhance oxygen delivery through the body and squeeze more performance out of humans. The only question is will these approaches be considered legal.”
The answer to improved athletic performance might be in our mitochondria. In a person of average aerobic fitness mitochondria make up about 2 percent of each cell’s volume; in well-trained athletes it is 4 percent. In the hyperkinetic hummingbird the number climbs to around 40 percent, giving hope that perhaps human cells could accommodate more mitochondria, thereby boosting athletic ability. “Of course there’s a limit at which point you just can’t cram any more mitochondria into a cell, but I think in humans there’s room left,” Weyand says. “Sports have become such a global, lucrative and professionalized endeavor that as long as there’s money to be made and fame to be won, we’ll continue to see improvements.”
Any future biological tinkering may bring with it the same ethical and philosophical concerns that shroud performance-enhancing drugs.
Blood doping may not be going away but the future of record-breaking, for better or for worse, most likely lies in the human genome. Gene-editing technologies like CRISPR–Cas9 now allow specific genes to be turned on, off or introduced—granting modifications that could confer any number of athletic advantages and that, as Weyand warns, would be nearly impossible to detect. “I do think we’ll see people trying things like CRISPR to introduce certain genes in the interest of athleticism,” David Epstein, author of the, says. “I think the main reason why people aren’t doing this yet is that so many forms of traditional doping are available and effective. They haven’t needed to move on yet.”
David Epstein, whose 2013 book The Sports Gene: Inside the Science of Extraordinary Athletic Performance explores the limits of human performance, points out that current concerns over CRISPR are often dismissed, given the complexities of our genetic code and the fact that at the moment we don’t actually know what most genes do. Yet, as featured in his book, there are examples of specific gene variants that result in enhanced athletic performance.
One such case involved Finnish skiing legend and seven-time Olympic medal winner Eero Antero Mäntyranta, who had runaway success throughout the 1960s, and was widely assumed to be blood-doping. Years later a genetic study on Mäntyranta and his family revealed that he carried a gene that greatly increases red blood cell mass and hemoglobin levels, the molecule that carries oxygen in blood. Epstein also cites the so-called “super baby,” an alarmingly muscular boy born in Berlin in 1999. The now-teenager has a mutation that blocks the production of myostatin, a protein that limits excessive muscle growth.