
Do You Lose Speed Faster Than Endurance?
From PodiumRunner “Ask Pete” Column

I’m linking directly to this article or Q&A from Coach Pete Magill’s column on PodiumRunner (used to be Competitor.com) because it’s relevant to our audience. The question was in reference to loss of speed & endurance as we age.
There’s been numerous studies over the years from RunnersWorld & the New York Times regarding this topic. The good news is that lower endurance capacity does not automatically mean slower running speeds. The reality is it’s just much more difficult to maintain the faster speeds as we age. The reason is older runners have a shorter stride length & actually push off more “weakly” than younger runners.

In a 2015 study, researchers found that leg muscles age earlier than other muscles in the body. Also leg muscles’ repair systems weaken earlier than other muscles. The take away to maintain more our speed as we age is to strengthen calf and ankle flexor muscles.
Coach Magill goes into a little more detail in his post. He follows with a detailed recommendation to complete various training exercises & even some diet advice to help repair tissues broken down by hard workouts. Go ahead and start reading the article below and click through to finish.
How Strength Training May Help
Paul DeVita, published a famous study where he showed older people, when they walk, take shorter steps than younger walkers. He also found that older people also rely less on the muscles around their ankles and more on the muscles around their hips to complete each stride than do younger walkers.
In a more recent study, he observed that older runners (40+ years old) showed much less activation of and power in their lower leg muscles, especially around the ankle and in the calf. Basically, there’s a shift away from reliance on the lower-leg muscles during running as we age.

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?