Mad calf disease
Mad Calf Disease is annoying and if you're north of 40 years in age you'll catch it sooner or later.
When I was younger my calves might get sore. This, through the first run of the year in spikes or racing flats. Or, after a track workout featuring shorter, faster intervals. That's not "mad calf" and, in any case, this soreness lasts a few days, not several weeks (as is the case with mad calf disease).
What I'm referring to happens at any speed, but generally to runners in or entering their 40s or 50s. Whether middle-agers new to running, or those returning to the sport of their youth, that maddening pull or strain accompanying a run even at the slowest of paces will take weeks to mend every time it strikes.
This doesn't typically happen to younger runners. Why us oldsters? The extra weight we carry? Probably not, because this did not happen to us in our youth while carrying water bottle packs, or running uphill. Less elastic, or less capable, soft and connective tissue? Maybe.
In my experience, it's metabolic. But it took me years to realize it. What starts out as an apparent strain, getting worse as I continue to run on it, is not a strain at all. It's a spasm. But it's minor, and doesn't seem like a cramp. It's not an injury when it first manifests itself, but it becomes one if and if and when I continue to run.
The solution? When you feel it, stop running and start walking. Walk for another minute after the sensation goes away. Resume running. If it comes back later in the run, repeat the remedy. If you do this, your calves will remain whole.
Why did I not discover the solution for better than a decade after first experiencing this? Because I never used to truncate a run — I just ran through a calf strain. Sometimes, the solution above is inconvenient. What if it happens in a race? Then you have a choice: save your race, or save your calf.