Anson Henry is a two-time Olympian. The sprinter knows what it's like to push his body to its limit on the world stage.

"There's a lot of luck that comes into play. A lot of timing that is out of your control. And you've just got to do what you can within your own training so that you can have your best performance every four years at the right time."

But as the Winter Olympics begin in Pyeongchang, some scientists are wondering how much faster, higher and stronger human beings can get?

One recent study, published in the journal Frontiers in Physiology, concluded that — after more than a century of pushing the boundaries of our bodies — a plateau has been reached for both sexes.

The researchers analyzed athletic performance data going back to the start of the 20th century. After more than 70 years of record-breaking trends, performance starting levelling off in the 1980s.

Simply put, our bodies have peaked. And that may mean fewer world records will be smashed in the coming years.

"This suggests that modern societies have allowed our species to reach its limits. We are the first generation to be aware of this," wrote co-author Dr. Jean-Franç​ois Toussaint, a cardiologist and professor of physiology at Paris Descartes University.

At McMaster University in Hamilton, Ont., kinesiology professor Stuart Phillips understands what it takes for the body to max out its potential. He holds a Canada Research Chair in skeletal muscle health and is an expert in athletic performance.

Phillips watches as his student, Sara Oikawa, puts on an oxygen mask, steps aboard a stationary bike, and starts to pedal. It's a test Phillips says can accurately predict how far she can push her body.

When you think about your athletic limit, you might be at your limit, says former Olympic sprinter Anson Henry. (Craig Chivers/CBC)

"It's an acute example of measuring peak performance — the peak at which her body can operate and take up oxygen — and will be dictated at a point where her muscles can no longer generate the power output to turn the pedals here," he says.

A number's game

Phillips says he believes that athletes in some sports, such as track and field, may be approaching the height of what their bodies can do. However, there will still be ways to shave nanoseconds off of records, he says. And that's because performance isn't just a matter of biology.

"It's a numbers game. It's about aligning the right genes with the right time and then the right physiology with the right mental makeup as well," he says.

After she won gold for women's freestyle slopestyle at the 2014 Winter Olympics in Sochi, Russia, Canadian skier Dara Howell felt she may have reached the top of her game. (Morry Gash/Associated Press)

Dara Howell hopes her numbers come up again in Pyeongchang. In 2014, she won the first Olympic gold medal in ski slopestyle. But after the excitement wore off, she started to doubt herself.

"Definitely, post Olympics, I thought I had peaked."

Howell stepped away from the sport for awhile — until she realized there are more goals to pursue.

The Olympic motto may be "Faster, Higher, Stronger" but a new study suggests athletes' bodies have physically peaked. A study published in the journal Frontiers of Physiology looked at athletic performance over the past 120 years. Researchers found "a trend toward a plateau during the last three decades for both sexes" 3:01

"I've grown so much in strength. ​Physically and mentally I feel in the best shape I've ever been in. Mentally I feel just solid. I feel I understand the ebbs and flows a bit better."

So while scientists can crunch numbers and conclude that humankind is reaching its athletic capacity, how do competitors know when their best days are behind them?

Stuart Phillips says a lot of it comes down to instinct. "I do think athletes have a fair sense of where that is. They know what it feels like. They know mentally what the rehearsal requires to get them to that stage."

Peak performance is not only a matter of biology, says kinesiologist Stu Phillips. (Craig Chivers/CBC)

Anson Henry says he knew his sprinting days were over soon after the Beijing Games in 2008. It was getting harder and harder for him to maintain an optimal level, both physically and mentally.

"When you think about your limits, you might be at your limit," he says.

Redefine success in sports

Researchers say that if athletes have maximized their performance levels, we may have to change how we define success in sports. Organizers will have to create new categories of records or change the rules.

However that doesn't mean fans should resign themselves to duller sporting events.

As Henry points out, there's still an elusive X factor that comes into play. Performance does plateau, but there are other aspects to a competition as well, he says.

"Breaking records is entertaining, but there is that anticipation that if everyone is at their peak, who's going to be able to rise to the occasion that day?"