My running buddy Leah, a co-worker and friend, runs at noon with me two or three times a week. We both came back to running from long layoffs due to injuries in 2011 and have worked diligently since then to get back into shape and maintain it.
I was always faster than her, by a lot. Before my layoff, where I put on a lot of weight, Leah and I wouldn't run together except on certain occasions like, say, an evening Holiday Season Festive Lights run from work.
That was, Back Then. Now she's faster than me and makes me work to be able to even hang with her on our noontime runs.
I saw this coming while we were training for the Navy-Air Force Half Marathon in mid-September last year and suddenly I was seeing nothing but the back of her on hills and I couldn't catch up, and on the flats too unless I made a conscientious effort to get even with her and stay there. She posted a 1:50:59 at that race, a huge PR of over 20 minutes, and I came in at 1:54:53, my second slowest half marathon.