In about half of the races I compete in, a masters athlete walks away with overall first place. A 42-year-old woman won Sunday's sprint tri in an astonishing 1:16:08.4, fifteen minutes faster than the next wave of us; and another 42-year-old woman won my last running race, the Fox and Hound 5K in downtown Cincinnati, in 20:17, approaching a National Class (gender- and age-graded) time. I try to size up the competition before each race, but it's usually hard to tell who's in my age group by appearance, because the masters athletes often look far younger than their age.
There are 2006 tables that predict running performance by age, averaged over thousands of people. In these tables, natural running ability ramps up quickly through your teens to your early twenties, maintaining a peak until 28 or 30. You should therefore never express surprise that a thirty-year-old beats a teenager; they're supposed to! After that, natural running ability ramps down more slowly on the other side of 30. Trained people in their forties are identical to trained teenagers, still at 89-97% of peak.
Except for those races where the college cross country team shows up, my own age group is often the toughest competition there! However, I sometimes refrain from even telling people I won my age group; I can see their eyes glaze over imagining waddly "middle-aged" ladies in track suits as my co-competitors. "Well of course you did," the sarcastic bubble over their head says! Sometimes I'd like to ask the 42- or 50-year-old winner if I can take her picture, just to show people who aren't there what I'm talking about, but that would seem kinda weird....
I could go on too much and too long about how our society uses age as an excuse for, well, everything. It's not that there are no effects of age; it's just that they're far less than everything we pin on it. One book goes even further in breaking down performance deterioration in these tables, separating inevitable physical changes from most runners' choices to train less and less intensely as they get older. The authors speculate that only 20% of the full decline in the tables is actually unavoidable, if you kept training.
I realize that not everybody likes to go to the track once a week and run fast half-mile repeats as much as I do. I've always had a skewed idea of fun in that way. But there are small ways to add intensity to exercise that usually make doing it more interesting for most people. Mostly I think it starts with entertaining the idea that while age isn't, well, just a number, it's not always as big a number as all that, either.