I like to walk/jog to warm up before tennis (I too prefer singles) but I'm fortunate that next to the courts is a cushioned track so it is much easier on the joints. I wouldn't run on cement though to save wear and tear as I near forty. The problems didn't seem to start until after I lost access to a red clay court.
(4) Volkl PB 10 Mids
Babolat Tonic+ 16/Babolat RPM Team 17 @ 51 lbs