.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... She is not available the morning I call for an interview. It’s Monday, so Renee Economides is out with the ladies, masked and sneakered, power walking their usual three miles around El Oso Grande Park near her home. From there, she is heading to the gym for a Silver Sneakers fitness class for seniors and to lift weights, so maybe we can chat in the afternoon, her daughter suggests. This is just the beginning of Economides’ six-day regimen, which includes a weekly 10-mile bike ride up the Tramway trail, two additional three-mile walks, two additional gym workouts and two mornings of 1½-hour aerobics classes she has taught for the past 32 years.