When I moved to Reston in 1976, tennis was big. There were a number of recreation areas with multiple tennis courts, tennis leagues, and tennis coaches. That soon declined. The Southgate area which had 4 courts, converted two to basketball. I've not noticed anything on the leagues and teaching in recent years and seldom see anyone playing on the one set of courts I pass with some regularity.
Horse riding was a part of the early Reston, but when I arrived the stable was on its last legs. The building finally collapsed a few years after I arrived, which led to a long fight within Reston Association about whether to rebuild or convert the stable and riding area to other uses. The other uses finally won, so a parking lot, two basketball courts, and a soccer field went in, a sign of the sports which were popular then.
By the early 2000's construction was booming and so was soccer. The soccer field, by which I pass on the way to my garden plot, was very busy. Youth teams, and teams of young men, probably mostly Hispanic immigrants, were were omnipresent on the weekends and I suppose in the evenings.
Then came the recession and the collapse of construction and then the recession of immigration from the area. First the men's teams were no longer evident, then the youth teams dwindled away. While in the early years the maintenance people had problems keeping the grass growing, especially in front of the goals, there's no problem now.
As a capper, this trend has been confirmed by the media authority, the NYTimes, in this
article