Now that you are 4 weeks into your marathon training program, you will start to get into longer runs on the weekend. This post is to give you some background on how to approach your long runs.
As you build your long runs, be careful to not look too far into the future to avoid overwhelming yourself. This is particularly important for the first time marathoners. Take each long run as it comes. You may finish a 14 mile run and think, "how could I possibly go any farther? I'm exhausted after 14 miles." Don't panic! You will find that each long run will lead to adaptations with the body improving strength and endurance. When you go out for 16 miles, you will be just as tired at the end as you were at 14 miles, but you have run 2 miles LONGER. Adaptation (physiological stuff - such as increased blood volume, great efficiency, increase burning of fat as fuel, great mitochondrial efficiency, greater storage of glycogen, etc.) has occurred. This is all GREAT STUFF! But, none of this is ever "easy." Running is work, and work is hard. Nothing great comes without hard work (just in case you were thinking running the Buffalo Marathon was going to be easy... I will put that misbelief to rest!).
Why are some weekend long runs LONGER and others SHORTER? You will notice that the long runs gradually get longer. However, once you get to 18+ miles there are occasional weeks that the run is shorter. This is built in recovery. It's not a good idea to run 18 - 20 miles every weekend because it will fatigue the body and not allow recovery (unless you are a high mileage runner or coming from an Ultra marathon background). Recovery is often overlooked in training. I have put in recovery weeks to make sure you do not over train. Enjoy when there is a "shorter" long run!
How long should your longest run be? This depends on several factors including your experience level, your weekly mileage, and your running pace. There are different philosophies on mileage for marathon preparation. My approach is conservative. This means I want you to get the MOST benefits from the LEAST amount of running to keep your body healthy and ready for marathon day. My general rule is to cap the longest runs you do at 18-20 miles, or 3:30, whichever you reach first. For the individual running 7:00 pace, it's going to be no problem to get in 20 milers. For the individual running 10:00 pace, you will reach 3:30 BEFORE you reach 20 miles. I encourage you to STOP at the 3:30 time. Why? Running longer than 3:30 takes much longer for the body to recover. You will need 4-5 days easy days, if not more, to allow full recovery. This leads to backing down training for additional days (lost training time). If you stop at 3:30, your body will recovery in the proper time to allow you to continue the training schedule. I know what you are thinking... if I don't run longer than 3:30/18-20 miles in practice, HOW DO I KNOW I CAN FINISH IT ON MARATHON DAY? There's this thing called training adaptation. As you build your long runs, and put the time running on your feet, your body is getting stronger, gaining endurance, and improving efficiency (those physiological adaptations). While you can't go run 4-5 hours every weekend in training, you CAN do that by the end of the training because of the physiological training adaptations that have occurred (increased blood volume, increased efficiency, increased use of fat for energy, great storage of glycogen/fuel, for example). You do need to trust yourself and trust the training.
For my first time marathoners following the BEGINNERS program, I have your long runs built on a Run/walk cycle of 9 minutes running/1minute brisk walking. By starting your long runs with this approach, your body will be able to build endurance. Do not wait until you are tired to put in the walking, as you will end up walking much longer than 1 minute period. The idea behind 9min run/1min walk is to provide a short break to drink & recover while not loosing your rhythm. A longer break will cause you to loose your stride rhythm and when you go to start back into your run, it will feel more difficult. Keeping that consistent cycle of 9/1 will allow your body to continue for a long period of time.
The next thing to cover with the long run is nutrition. That will come in the next post. If there's a topic you want me to cover, feel free to let me know!