Not counting thanksgiving week, I have four weeks to train for a turkey trot. I can currently run at 5 x 1k with 2:30 rest at my desired race pace per mile -- but I am exhausted afterwards. In those four weeks what are some suggested workouts to get me to the race? 3 x 1m at race pace with 2:00 rest? 6 x 1k with 90 sec rest? How many of these should I be doing every seven days? Is 2x a week too much?