The slipstream is the zone behind a person moving (walking, running,etc) which pulls the air along with the person.In the racing world it is known as drafting.
A recent news article about a study done by Belgian engineers has gone a bit viral itself.The wave of air flowing carrying respiratory droplets or drops in the wake of a runners goes behind him for distances greater than the magic 6 feet that we are admonished to respect as regards proximity to other humans in the world or preventive social distancing. At least the animations released by the researchers give that impression as do their data which at this writing has not yet been published in a peer reviewed journal.
See here for details.
If their animations reflect the actual path of exhaled particles,one might decide that even when you are out for a run to wear a mask at least some of the time.
See here for some questions and answers from one of the authors of the paper.
My personal take home is that when a runner passes me I should move to the side to avoid potential particles in his slipstream and ( with an abundance of caution) pull my mask up until the passer is 20 to 30 thirty feet away. In the increasingly unlikely instance in which I actually overtake a runner and pass her I should move to the side and keep to the side to keep the passed person out of my slipstream.
Perhaps the equivalent of "My mask protects you,your mask protects me" for runners could be
"I'll keep you out of my slipscreen,you keep me out of yours"
According to the authors data a cyclist should stay 60 feet directly behind the bike in front or keep off to the side. Also they suggest that 16 feet behind a walker and 32 feet behind a runner to be approximations of the "aerodynamically equivalent social distance" which is six feet for stationary people.