No matter the race for which you are training, the long run is a key part of your weekly training. If you’re planning to run your first 5k or your 50th marathon, the major goal of the long run is the same: To improve your endurance and make yourself better able to complete the race distance. That’s a large task by itself, but as training becomes more advanced and you really want to “race” a long distance (we’ll focus on the marathon in this post for simplicity), the long run has multiple additional training effects, depending on how you approach it:
- Training the body to burn primarily fatty acids as fuel (Long Slow Distance)
- Training the digestive system to process additional fuel for glucose replacement (Fueled Long Run)
- Training the body to maintain race pace under simulated race conditions (Long Run with Quality)
Long Slow Distance: When most people think long run, this is what they think. And for good reason. Most of your long runs (especially as you add distance) should be of the easy variety. The pace is generally a minute or more slower than marathon goal pace, and the only real goal is to complete the run. However, I differentiate this type of run from others in that my LSD runs are minimally fueled. If the effort is low enough (generally at or below 150 bpm for most adult runners), the body will burn almost entirely fatty acids as fuel, so none is needed during the run to replace what is used (your muscles have a huge stock of fatty acids to burn, unlike glycogen which only lasts several minutes before it needs to be replaced). The only “catch” is that fatty acids need a small amount of glucose to be burned (based on the metabolic process, where mitochondria convert substrate into ATP for energy…blah blah blah…just remember that fat only burns in a glucose/glycogen flame). So I either start LSD runs well-fueled or I take some calories early in the run. The most important thing here is the effort: EASY.
Fueled Long Run: In addition to general endurance, a fueled long run trains your stomach to deal with processing calories on the run. The only way to avoid cramping or getting sick during a race, and also to ensure that you can replace the glycogen stores you are going to be using in a race, is to take calories on the run. The type and schedule for consumption is very runner-specific, so you need to experiment until you find something that works for you (I personally like to practice with what I know will be offered on the course, so that I have the option of not carrying my own calories during the race). The pace/effort is not a concern here, the focus is on learning your schedule and getting accustomed to it.
Long Run with Quality: This is the final piece in the puzzle. For a marathon, these runs should consist of some easy running (to get the body fatigued), then some work at goal race pace (or faster, depending on the approach) at the end of the run. I have my athletes run 5k segments at goal pace in the second half of a 20+ mile run, or some mile repeats at half marathon pace. All these runs serve to train your body to use all available fueling systems, and they also train the most important part of a marathoners body: the brain. The most important lesson for race day is: “I can still run hard when I feel tired.” These runs should also feature calories, just like in the race, so that you know how your body reacts to food in your stomach when you are running race pace.
Make sure you are integrating all these long runs when you are focused on a long race where a PR is on the line. When you get to the starting line, make sure that all the tools you need for the race are sharp and ready to go!