We are heavy into marathon season now, and I am seeing a lot of conversation about the 20 mile training run. How many 20 milers should you have in your plan? Should you run 20 miles? Why stop at 20? Why not 22 or 24? Or even over-distance like some half marathon plans would have you do?
There are a lot of answers to these questions, and the answers depend on how long you’ve been running, how fast you are, and how your training plan is structured.
1. There is a lot of research showing that any run over three to three and a half hours does more harm than good. If you buy into this research (and you should), whether or not you do a 20 miler depends on your pace. You want your body to recover from your training run — without loading up on extra rest days– so that you can continue doing the training that will get you to your goal. If you run at a pace that would keep you out running more than three hours, it’s a good idea to look at a plan that would give you the training effect of the 20 mile run, but in a way that is less damaging to your body. (For example, breaking that mileage into a Friday and a Saturday run, or a morning and an evening run.)
2. Running over 3 hours increases chance of injury. To expand on point number one–if this 20 miler takes more than 3 hours, you are at risk for increased injury. Your form suffers. You ignore aches and pains that tell you to rest. You get repetitive motion injuries. And on and on. You want to make it to START (and the finish!), right?!
3. Weekly mileage comes into play. Your long run should not be more than 50% of your weekly mileage. Are you running 40+ miles a week? Then, you might be able to handle 20 mile training runs. Runners place so much emphasis on the 20 milers that their training week revolves around this long run. What tends to happen to less experienced runners is that this 20 mile run is often 2/3 of their weekly mileage, and that run now requires a rest day before, and maybe 2 days after… and all other training is thrown out the window… because of the “importance” of this big 20 mile run.
4. A good plan takes into consideration how your body adapts to the training load, and it helps you prepare your mental game. SO… if you are a runner who thinks there is no way you could possibly complete a full marathon with only a 16 mile run, or only a 20 mile run, or only a 26 mile run… then go ahead and do that run as a confidence booster. But, know that a run longer than 3 hours will be hard on your body, and structure your plan around building proper mileage and getting enough recovery time.
If you’re getting close to race day, you’re already locked into a plan. If you’re having trouble recovering from your long runs, I’d suggest the following changes as you select a plan for the spring marathon season.
1. After your fall races– REST. Take a few easy weeks. Cross train. Let your body recover from your fall marathon.
2. Slowly build up mileage. Begin building your base mileage so that your spring plan has a sufficient base to support the long runs that will come at the end of the plan. (My personal plan is to slowly build mileage so my spring training, which will start around Thanksgiving, is based on 50+ mile weeks.) Building a base takes time. Endurance is the most important part of a marathon plan. Plan ahead. If you know the 20 milers are important to you, build that goal into your plan by starting with a base that will support the mileage you intend to run as you approach race day.
3. Remember the 10% rule. Don’t jump in mileage by more than 10% each week. And don’t increase mileage and intensity in the same week. Training is not about being a show off. It’s about getting to your goal safely. It really doesn’t matter what everyone else in your training group, or on Facebook, is doing.
4. If you are not running 40+ mile weeks, then consider the back-to-back long run as a safer way to build training volume. Split the runs something like: Saturday 8, Sunday 12 or Saturday 10, Sunday 10. You’ll reduce the risk of injury, and you will be running on “tired legs,” which mimics way your body will feel in the last miles of the marathon.
5. Remember the long run is just ONE key workout of the week. While the long run is very important, you want to make sure that your body is ready for this challenge. The various coaching methods schedule these key workouts in different ways, at different times. But, generally, your plan should include long runs, tempo runs, and speed work. If a workout earlier in the week leaves you so tired that it compromises the quality of one of the key workouts on your plan, it’s time to adapt the plan. It’s better to cut back somewhere (duration, intensity, etc), rather than to spend extra days on the couch resting, which amounts to inconsistent training…. or pushing yourself so hard you are injured.
So, about that 20 miler… it’s all about patience. The key is to structure your plan in a way that helps you safely get in the necessary training to hit your race day goals.
UPDATE: I received a lot of questions about fueling and splitting these long runs. I went to the Lydiard Foundation’s Lorraine Moller (1992 bronze Olympic women’s marathon medalist) and Nobby Hashizume for some expert responses. You can read their responses in this post.
I am a Lydiard Level II Running Coach and a Newton Running Coach. After many years of being a chronically injured runner, I have learned from my training mistakes–too much, too soon–my goal is to help others hit their race day goals as they train in a smarter, more consistent manner.