P, that depends on the amount of time between the IM and the Ultra. I know you don’t have an event in mind yet, so here are some guidleines:
1. If the Ultra will be 10 weeks or more after the IM, make no change. Just pick up the Ultra plan for the last ~10 weeks of the plan after the IM (but give yourself 1-2 weeks off after the IM to rest).
2. If the Ultra is less than 10 weeks after the IM, make these two modification for the last 8 weeks of the IM:
– add 30 minutes to your longest run each week, but don’t go longer than 3.5 hours for any given long run.
– add a second 1-hour run to Tuesday, Wednesday, or Thursday. Best to make this an AM and PM run.
David