Later, in her favorite event, the hammer throw, Kotelko took her place on the pitch with the other competitors — younger women she competes alongside, though not strictly against, since at this meet she was the only woman in the 90-and-over category. She removed her glasses. She swung the seven-pound cannonball around her head — once, twice, three times — and the thing sailed, landing with a thud, 45.5 feet away. “If I spun I could throw it farther,” she admitted later, but after watching somebody very old fall that way, she has decided not to risk it.

EXERCISE HAS BEEN shown to add between six and seven years to a life span (and improve the quality of life in countless ways). Any doctor who didn’t recommend exercise would be immediately suspect. But for most seniors, that prescription is likely to be something like a daily walk or Aquafit. It’s not quarter-mile timed intervals or lung-busting fartleks. There’s more than a little suffering in the difference.

Here, though, is the radical proposition that’s starting to gain currency among researchers studying masters athletes: what if intense training does something that allows the body to regenerate itself? Two recent studies involving middle-aged runners suggest that the serious mileage they were putting in, over years and years, had protected them at the chromosomal level. It appears that exercise may stimulate the production of telomerase, an enzyme that maintains and repairs the little caps on the ends of chromosomes that keep genetic information intact when cells divide. That may explain why older athletes aren’t just more cardiovascularly fit than their sedentary counterparts — they are more free of age-related illness in general.

Exactly how exercise affects older people is complicated. On one level, exercise is a flat-out insult to the body. Downhill running tears quadriceps muscles as reliably as an injection of snake venom. All kinds of free radicals and other toxins are let loose. But the damage also triggers the production of antioxidants that boost the health of the body generally. So when you see a track athlete who looks as if that last 1,500-meter race damn near killed him, you’re right. It might have made him stronger in the deal.

Exercise training helps stop muscle strength and endurance from slipping away. But it seems to also do something else, maintains Mark Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Hamilton, Ontario (who also happens to be a top-ranked trail runner). Resistance exercise in particular seems to activate a muscle stem cell called a satellite cell. With the infusion of these squeaky-clean cells into the system, the mitochondria seem to rejuvenate. (The phenomenon has been called “gene shifting.”) If Tarnopolsky is right, exercise in older adults can roll back the odometer. After six months of twice weekly strength exercise training, he has shown, the biochemical, physiological and genetic signature of older muscle is “turned back” nearly 15 or 20 years.

Whether we are doing really old folks any favors by prescribing commando-grade training, well, “that’s the million-dollar question,” Hepple says. “Olga can obviously handle it. But most people aren’t Olga.” In general, kidneys and other organs tend to have trouble managing the enzymes and byproducts produced when muscle breaks down. Inflammation, which produces that good kind of soreness weekend warriors are familiar with, “also damages a lot of healthy tissue around it,” notes Li Li Ji, an exercise physiologist at the University of Wisconsin, Madison. “That’s why I usually discourage older people from being too ambitious.”

Yet if there’s a single trend in the research into exercise and gerontology, it’s that we have underestimated what old folks are capable of, from how high their heart rates can safely climb to how deeply into old age they can exercise with no major health risks.