All sprinters wage war against the stopwatch, making time and not the competition an individual athlete’s greatest enemy. Few battle the clock as successfully as Kim Collins.

Collins, a four-time Olympian in the 100 meters from Saint Kitts and Nevis in the West Indies, celebrated his 40th birthday in April, less than one month after becoming the oldest male participant in the history of the IAAF World Indoor Championships.

To put his age into perspective — and to give an idea as to how rare it is to see a 40-year-old sprinter remain a fixture in outdoor and indoor competition — consider this: Collins made his Olympic debut at the 1996 Atlanta Games, meaning he’s spent half of his life on the international stage.

Or, think of it another way, he is twice the age of 20-year-old American Trayvon Bromell, who outpaced Collins in taking gold in the 60 meters at this spring’s indoor championships in Portland.

So what’s the key to turning back time? Younger track and field athletes who come to Collins for advice are given a simple recommendation. Don’t just try to get fast, Collins will say, but dedicate yourself to conditioning.

“The key to doing track and field for so long is that the body remembers,” Collins said. “So once I get fit I have no problem, because I’ve been doing it for some many years. Once you get fit first, it’s easy for anybody to last as long as I have in this sport.”

This summer’s Rio Games will mark a return to Olympic competition after Collins’ controversial departure from the 2012 Games in London: Saint Kitts and Nevis officials sent him home before the start of the Games after Collins left the Olympic village without permission to spend a night with his wife and coach, Paula, and their children.

Time has helped to heal that wound. As he prepares for his fifth Olympic Games — the most by any athlete from Saint Kitts and Nevis — Collins remains focused on the clock, not his age, even amid reminders of his elder-statesman status within the sport.

“It’s crazy when these young guys come and tell me their mom and dad are big fans,” he said. “But my thing is, if I’m going to quit they’re going to have to beat me and make me quit.”