This explains why Achilles tendon and calf injuries tend to increase” as runners get older. So it makes sense that in order to lessen the chance of such injuries and potentially also maintain more of our speed as the years pass, we probably should consider strengthening our calf and ankle flexor muscles.
Technically, speed goes first, but the outcome for distance runners is a loss of endurance.
First off, before I explain more, don’t get mad. Every time I address age-related performance decline in running, some readers get upset. Age is just a number, they write. Fifty is the new forty. Yadda yadda yadda. I agree with all that. But I also believe that the more we explore the issues facing aging runners, the better equipped we are to meet them head on with smart, effective training.
I’m an aging runner myself. And, like everyone else, my age 55–59 record (15:42) is slower than my age 45–49 record (14:34)—over a minute slower. I don’t know about you, but I want to know why I’m slowing down so that I can put on the brakes of that process. Which brings us back to the question: speed or endurance?
Let’s start by looking at American records for speed and endurance in three different age groups. That’ll give us an idea of who gets hit hardest by the aging slowdown. The following table shows age group records, then lists the percentage of slowdown for athletes in the older age groups (versus the age 39-and-under record): via Ask Pete: Which Goes First with Age—Running Speed or Endurance?