I am planning a marathon on 18th of June. My plan was to use the Marathon Level 1 plan. I have also planned one week of snowboarding early March, which would coincide with the third week of the plan. It will be impossible to perform running activities during that week.
What would you recommend? Start the plan one week earlier, resuming the plan at week 4 after my snowboard break?
Yes, go ahead and start the plan a week early. You’ll be active during the missed week, so you won’t go backward, and the transition back to the plan should be smooth, given how early in it you will be.