Finding The Right Balance
If you’re still determined to run the marathon as part of your training, either to enjoy the experience, help a friend, or what have you, you can always cut back on the total distance by either jumping in at 5-6 miles or stopping at 20-21 miles, or the point when your long run would normally end.
If you’re pacing a friend, the start of a race is too congested to be of much assistance anyway. You’re better served jumping in at 6 miles (when the crowds begin to thin out) and being a little more fresh during the last 6 miles to help give the pacing and motivation your running partner needs.
Conversely, if you’re running the marathon just to enjoy the experience or have some company, starting the marathon still allows you to appreciate all the pre-race energy and excitement. However, stepping off the course at 20-22 miles will allow you to recover faster and keep your training schedule on track. Since you’re not running for a time, and just want to enjoy the experience, not finishing shouldn’t be an issue.
As I’ve mentioned before, it’s important to find the balance between the optimal training schedule and getting the most enjoyment from your running. However, in this case, running a marathon as part of your training just doesn’t make sense. Get creative or think about the big picture and you’ll enjoy success at your goal race and keep training fun.