Eliud Kipchoge’s extraordinary sub-two-hour marathon in Vienna on Saturday is one of the greatest sporting achievements—recording a time that has never been achieved before, again. It is a time on the fringes (边缘) of what scientists believe is humanly possible.

“It is a great feeling to make history in sport after Sir Roger Bannister in 1954. I am the happiest man in the world to be the first human to run under two hours and I can tell people that no human is limited,” Kipchoge said afterwards.

Is he right? Where are the limits of human ability? And how close are we to reaching them?

Raph Brandon, head of science for England cricket, distinguishes between achievements which are constrained (限制) by human anatomy (解剖学), and those which require human determination or skill.

“When Bolt ran 9.58 in Berlin 10 years ago, if you analyse the split times it’s very hard to imagine where the improvement comes from,” said Brandon, “The Usain Bolt 100m or the two-hour marathon, they’re in that category.”

Multi-day, ultra-endurance events, such as Thomas’s cross-Channel swim, are different, Brandon said.

“They need determination, psychology and bloody-mindedness to go that little bit further. Those people will continue to do unique things because you’re not really taking the body to its anatomical limit. It’s more a question of how much you’re prepared to consume and exhaust yourself.”

And there’s a third category, those sporting endeavours (努力) that rely on hand-eye coordination: the goal tallies of Cristiano Ronaldo and Lionel Messi, and the batting of Virat Kohli Steve Smith or Don Bradman, who trained by hitting a golf ball with a stump against a wall to become the best batsman ever to play Test cricket.

Equipment has been a factor for many sports. NFL receivers wear gloves that enable them to make improbable one-handed catches. The GB cycling team swept the board at the Olympics because of their amazing new clothing tech.

The line between what is fair and unfair is blurry. Kipchoge’s sub-two-hour run will not be officially recognized. He ran behind a car which beamed a green laser on to the ground in front of him. Teams of pacemakers, 41 in total, ran in a v-formation to protect him from headwinds (逆风). He wore specially designed shoes and the time and date of the event were picked only after detailed weather forecasting.

Jo Davies, a sport psychologist, says recent studies have shown athletes can push themselves harder because of their perception of exhaustion.

Other research published this year which looked at athletes who had won multiple gold medals found that they were different in several important ways. They had often had a shocking and upsetting life experience and had suffered significant setbacks in their performance during their careers, as well as personality traits of determination, perseverance and perfectionism.

So whether or not those limits have been reached, there will be no shortage of people prepared to try to go beyond them.

As scientists around the world race to find a treatment for the coronavirus, a young girl among them stands out.

Anika Chebrolu, a 14­year­old from Frisco, Texas, has just won the 2020 3M Young Scientist Challenge ­­ and a $25,000 prize ­­ for a discovery that could provide a potential therapy to Covid­19 (or SARS­CoV­2 virus).

Anika's winning invention uses in­silico methodology to discover a lead molecule that can selectively bind to the spike protein of the SARS­CoV­2 virus.

"The last two days, I saw that there is a lot of media hype about my project since it involves the SARS­CoV­2 virus and it reflects our collective hopes to end this pandemic as I, like everyone else, wish that we go back to our normal lives soon," Anika told CNN.

The coronavirus has killed more than 1.1 million people globally since China reported its first case to the World Health Organization (WHO) in December. The United States has more than 219,000 deaths, according to data from the Johns Hopkins University Center for Systems Science and Engineering.

Anika, who is Indian American, submitted her project when she was in 8th grade ­­ but it wasn't always going to be focused on finding a cure for Covid­19. Initially, her goal was to use in­silico methods to identify a lead compound that could bind to a protein of the influenza virus.

"After spending so much time researching about pandemics, viruses and drug discovery, it was crazy to think that I was actually living through something like this," Anika said.

"Because of the immense severity of the Covid­19 pandemic and the drastic impact it had made on the world in such a short time, I, with the help of my mentor, changed directions to target the SARS­CoV­2 virus." Anika said she was inspired to find potential cures to viruses after learning about the 1918 flu pandemic and finding out how many people die every year in the United States despite annual vaccinations and anti­influenza drugs on the market.

After a car crash left 14-year-old Collin Smith paralyzed, doctors told him he had a 20 percent chance of finishing high school. The opportunity to attend college seemed even slimmer. Yet eight years later, Collin earned a bachelor of arts degree. He achieved the nearly impossible--with the help of a kind and generous man five decades his senior.

Emest Greene and his wife attended the same church as Collin and his parents did. The Creenes had moved to the area just nine months earlier. But when Emest heard about Collin' s accident and the fact that his parents would not be able to care full-time for him, he approached Collin's parents with the idea that he looked after the boy while they were at work. The Smiths gratefully accepted.

Emest sought training to care for Collin and then began arriving early on weekday mornings. He would help Collin get out of bed, wash, dress and have breakfast. Then he' d drive Collin to and from school. Then, while the two waited for one of Collin's parents to get home, "We played lot of Monopoly," says Emest with a laugh. At first, the age difference was a challenge but they learned to compromise. "Older folks are just older versions of you," says Collin. "Same people. great stories."

Some days were better than others. "He can't do for himself, so he can be demanding," says Emest. But he attests that Collin's strong will got him through tough times.

After graduation, Collin was accepted to nearby High Point University. Emest accompanied him to every class. On graduation day, Emest received an honorary degree in humanities.

"I was floored, "he says.

Collin wasn't surprised, however. "Emest is a godly example of the way a man should live-calm, modest," he says.