4. Improve your weakness. If run fitness is your limiter, train for one or two half-marathons. I like athletes to try a high-frequency (five to seven days per week) running routine for one to two months, moving into more race-specific workouts closer to race day. If cycling is your weakness, an indoor cycling power program can do wonders. I like to give athletes two to three interval-based workouts per week and one optional aerobic ride on the weekend. If swimming is your weakness, join a Masters group that will challenge you.