Assuming we are looking at a 5- to 6-week window between your first and second marathons, you are now at the 15- to 16-day mark or roughly 2 to 3 weeks out from marathon #2; it's time for a "normal" final 3 weeks with a couple of exceptions. Between 2.5 and 3 weeks out from marathon 2, and 2 weeks removed from the first, runners can look at a longer run of 16 to 18 miles. If you've done a good job of recovering in the first 10 days, your legs will feel refreshed enough at this stage to get in the one long run you'll need between the two marathons.
Execute one standard 18- to 22-mile run in the narrow midway window between the two marathons. However, do so at a controlled clip, roughly 45 seconds to 1 minute per mile slower than your target race pace. There's no need to do a marathon specific "harder" long run in the narrow 4- to 6-week window between marathons. The exceptions include the need for shorter runs in between days.
Learning from Jones
American Marathoner Kim Jones may very well be the master of close proximity marathons. On numerous occasions, Jones, one of the best marathoners in American history, ran multiple marathons in an 8- to 10-week window—most famously her second place at the 1989 NYC Marathon in a PR of 2:27, just 4 weeks to the day after winning the Twin Cities Marathon in 2:31.
Jones stresses the need for recovery first and foremost and having your legs under you as you approach the second race. "I felt pretty good after Twin Cities, but I was only running every day 4 to 5 miles," said Jones. After later dealing with some delayed onset soreness, Jones began to feel like her normal self in just a couple of weeks. "About two weeks before NYC, I felt great and did a 20-miler two weeks before New York." One of the secrets to both recovering well between two "close proximity" marathons and being primed and ready for the second is to make alternating training days short, as Jones did. For example, if you typically average 7 to 8 miles on non-specific training days, pull those days back to shorter runs such as 3 to 5 miles.
More: Recovery Runs
Preparation for 2nd Marathon Predicated on Fitness for the First
One concept virtually all coaches and experienced runners agree on is the need for overall fitness entering any marathon, let alone targeting excellence for a second race in a short window. Contesting two marathon races in a narrow timespan demands background and a solid block of consistent healthy training. This back-to-back approach can be successful if done properly. However, it's a strategy by and large meant for those with a significant background of training and experience.
What to do after your second marathon? Jones has advice for effective recovery coming off this rarely-seen double, or simply for those looking to rest properly after a normal "one and done" scenario.
"Take a month off. Go on vacation. Put your running aside for a while. If after two weeks you feel good, run maybe 10 minutes."Sign up for your next race.