as I said earlier, it took me three years to build up to doing these more than once a week. Be patient and take care of your legs and feet -- lots of self massage and stretching. I don't sprint until I am completely warm and stretched -- even if it takes a 45-minute warmup. Lately I get up at 6 a.m., jog to the turf for 7 a.m., and do a 75-minute workout three times a week that includes lots of drills and varied sprints. It took from age 49 to 52 to get to this point. Don't jump into this too quickly or you will get hurt. But you can regain a great deal of your speed and power. You just have to persevere and above all listen to your body.
This is my weekly schedule:
SUN -- 300 sprint, 100 jog, 100 sprint followed by 2x150.
MON -- sprints and drills; weights; 20-minute swim
TUE -- yoga class; 5x300 on grass; easy cross country
WED -- sprints and drills; weights; 20-minute swim
THU -- 40-minutes of cross country; yoga class
FRI -- sprints and drills; weights; 20-minute swim
SAT -- cross country or off
Yes, I obviously have time to do all of this. I'm self-employed and work from home, and I live across the street from a university, and also have a membership at a local YMCA. I have a supportive wife who's also very fit, so nutrition and activity are top priorities for us. I avoid running on the roads and I only do one workout per week (Sundays) on the track. The other sprint workouts are on astroturf, which is amazingly good on the joints. I've increased my speedwork by at least triple since starting on the turf earlier this summer.